PleasureCraft Engine Group 5.0L, 6.0L, 8.1L, 5.7L, MEFI 4 5.0L Diagnostic Manual

MEFI 4 / 4B

DIAGNOSTIC

MANUAL

5.0/5.7/6.0/8.1L

L510005P

11/05

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Marine Electronic Fuel Injection (MEFI 4 / 4B)

Contents

Section 1 - General Information ........................................................................................................................Page 1-1

Section 2 - ECM and Sensors ..........................................................................................................................Page 2-1

Section 3A - Fuel Metering System (5.0/5.7L) ................................................................................................ Page 3A-1

Section 3B - Fuel Metering System (6.0L) .....................................................................................................Page 3B-1

Section 3C - Fuel Metering System (8.1L) .................................................................................................... Page 3C-1

Section 4A - Ignition System (5.0/5.7L) ..........................................................................................................Page 4A-1

Section 4B - Ignition System (6.0/8.1L) ..........................................................................................................Page 4B-1

Section 5 - Diagnosis ........................................................................................................................................Page 5-1

Section 6 - PCV System ...................................................................................................................................Page 6-1

Section 7 - Symptoms .......................................................................................................................................Page 7-1

Section 8 - Master Speciﬁ cations ......................................................................................................................Page 8-1

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5.0/5.7/6.0L/8.1L General Information 1 - 1

Marine Electronic Fuel Injection (MEFI) Section 1 General Information

Contents

General Description .............................................Page 2

Visual/Physical Inspection ...............................Page 2

Basic Knowledge and Tools Required .............Page 2

Electrostatic Discharge Damage ..................... Page 2

Engine Wiring................................................... Page 2

Engine Control Module (ECM)

Self-Diagnostics............................................... Page 2

Malfunction Indicator Lamp (MIL) ................... Page 2

Intermittent Malfunction Indicator Lamp

(MIL) ......................................................... Page 3

Reading Diagnostic Trouble Codes

(DTCs) ......................................................Page 3

Service Mode ............................................Page 3

Normal Mode.............................................Page 3

MEFI On-Board Diagnostic (OBD)

System Check.................................................. Page 3

DLC Scan Tools ............................................... Page 3

Scan Tool Use With Intermittents..................... Page 4

How Diagnostic Trouble Codes Are Set........... Page 4

Clearing Diagnostic Trouble Codes

(Non-Scan) ...................................................... Page 4

Clearing Diagnostic Trouble Codes (Scan) ......Page 5

Non-Scan Diagnosis of Driveability Concerns

(No DTCs Set) .................................................Page 5

Aftermarket (Add-On) Electrical and

Vacuum Equipment...........................................Page 5

Use of Circuit Testing Tools...............................Page 5

Tools Needed to Service the System ...............Page 5

Service Precautions..........................................Page 6

Test Light Amperage Draw Test........................Page 6

Special Tools (1 of 3) .......................................Page 7

Special Tools (2 of 3) .......................................Page 8

Special Tools (3 of 3) .......................................Page 9

Abbreviations.......................................................Page 10

Diagnosis .............................................................Page 11

On-Board Service ................................................Page 11

Wiring Harness Service..................................Page 11

Wiring Connector Service...............................Page 12

Metri-Pack Series 150 Terminals..............Page 12

Weather-Pack Connectors........................Page 13

Micro-Pack 100/W Series Connectors .....Page 14

MEFI 4 - PCM

1 - 2 General Information 5.0/5.7/6.0/8.1L

near a highly charged object and momentarily touches

General Description

Visual and Physical Inspection

Important: This visual and physical inspection is

very important. Perform this inspection carefully and thoroughly. Perform a careful visual and physical inspection when performing any diagnostic procedure. This can often lead to repairing a problem without further steps. Use the following guidelines when performing a visual and physical inspection:

• Inspect all vacuum hoses for the following

conditions:

– Correct routing – Pinches

ground. Charges of the same polarity are drained off, leaving the person highly charged with the opposite polarity. Static charges of either type can cause damage. Therefore, it is important to use care when handling and testing electronic components.

Engine Wiring

When it is necessary to move any of the wiring, whether to lift wires away from their harnesses or move harnesses to reach some component, take care that all wiring is replaced in its original position and all harnesses are routed correctly. If clips or retainers break, replace them. Electrical problems can result from wiring or harnesses becoming loose and moving from their original positions, or from being rerouted.

– Cuts – Disconnects

• Inspect all wires in the engine compartment for the

following conditions:

– Proper connections – Burned or chafed spots – Pinched wires – Contact with sharp edges – Contact with hot exhaust manifolds

Basic Knowledge and Tools Required

To use this manual most effectively, a general understanding of basic electrical circuits and circuit testing tools is required. You should be familiar with wiring diagrams, the meaning of voltage, ohms, amps and the basic theories of electricity. You should also understand what happens if a circuit becomes open, shorted to ground or shorted to voltage.

To perform system diagnostics, several special tools and equipment are required. Please become acquainted with the tools and their use before attempting to diagnose the system. Special tools that are required for system service are illustrated in this section.

Electrostatic Discharge Damage

Electronic components used in control systems are often designed to carry very low voltage, and are very susceptible to damage caused by electrostatic discharge. It is possible for less than 100 volts of static electricity to cause damage to some electronic components. By comparison, it takes as much as 4,000 volts for a person to feel the zap of a static discharge.

There are several ways a person can become statically charged. The most common methods of charging are by friction and by induction. An e xample of charging b y friction is a person sliding across a seat, in which a charge of as much as 25,000 volts can build up. Charging by induction occurs when a person with well insulated shoes stands

Engine Control Module (ECM) SelfDiagnostics

The Engine Control Module (ECM) performs a continuous self-diagnosis on certain control functions. This diagnostic capability is complemented by the diagnostic procedures contained in this manual. The ECM’s language for communicating the source of a malfunction is a system of Diagnostic Trouble Codes (DTC’s). The DTC’s are two digit numbers that can range from 12 to 81. When a malfunction is detected by the ECM, a DTC is set and the Malfunction Indicator Lamp (MIL) is illuminated.

Malfunction Indicator Lamp (MIL)

The Malfunction Indicator Lamp (MIL) is part of the Marine Diagnostic Trouble Code (MDTC) tool, or it can be a dash mounted warning light on some boat models.

If present, it informs the operator that a problem has

•

occurred and that the boat should be taken for service as soon as reasonably possible.

It displays DTC’s stored by the ECM which help the

•

technician diagnose system problems.

As a bulb and system check, the light will come “ON” with the key “ON,” engine “OFF.” When the engine is star ted, the light will turn “OFF.” If the light remains “ON,” the self-diagnostic system has detected a problem. If the problem goes away, the light may go out, but a DTC will remain stored in the ECM.

When the light remains “ON” while the engine is running, or when a malfunction is suspected due to a driveability problem, the MEFI “On-Board Diagnostic (OBD) System Check” must be performed as the ﬁ rst step. These checks will expose malfunctions which may not be detected if other diagnostics are performed prematurely.

MEFI 4 - PCM

5.0/5.7/6.0L/8.1L General Information 1 - 3

Intermittent Malfunction Indicator Lamp (MIL)

In the case of an “intermittent” problem, the Malfunction Indicator Lamp (MIL) will light for 10 seconds, and then go out. However, the corresponding DTC will be stored in the memory of the ECM. When DTC’s are set by an intermittent malfunction, they could be helpful in diagnosing the system.

If an intermittent DTC is cleared, it may or may not reset. If it is an intermittent failure, consult the “Diagnostic Aids” on the facing page of the corresponding Diagnostic Procedure. Symptoms section also covers the topic of “Intermittents.” A physical inspection of the applicable sub-system most often will resolve the problem.

Reading Diagnostic Trouble Codes (DTC’s)

The provision for communicating with the ECM is the Data Link Connector (DLC) (Figure 1-1). It is part of the MEFI engine wiring harness, and is a 10-pin connector, which is electrically connected to the ECM. It is used in the assembly plant to receive information in checking that the engine is operating properly before it leaves the plant. The DTC(s) stored in the ECM’s memory can be retrieved two different ways. One way is with a Diagnostic Trouble Code (DTC) tool. The other way is through a scan tool,

A



A B C D E



K J H G F

DATA LINK CONNECTOR (DLC)



B



C



D



E

6-18-93

MS 13554

times. At the end of the DTC’s, the ECM will simply go back and start over with ﬂ ashing DTC 12.

Service Mode

When the DTC tool is installed at the DLC and “service mode” or “ON” is selected, the system will enter what is called the “Service Mode.” In this mode, the ECM will:

• Display a DTC 12 by ﬂ ashing the MIL, indicating that

the diagnostic system is working.

• Display any stored DTC’s by ﬂ ashing the MIL. Each

DTC will be ﬂ ashed two times, then DTC 12 will be ﬂ ashed again.

Normal Mode

When the DTC tool is in the “normal mode” or “OFF,” it has no affect on the engine operation.

MEFI On-Board Diagnostic (OBD) System Check

After the visual/physical inspection, the “On-Board Diagnostic (OBD) System Check” is the starting point for all diagnostic procedures. Refer to Diagnosis section.

The correct procedure to diagnose a problem is to follow two basic steps:

1. Are the on-board diagnostics working? This is determined by performing the “On-Board Diagnostic (OBD) System Check.” Since this is the starting point for the diagnostic procedures, always begin here. If the on-board diagnostics are not working, the OBD system check will lead to a Diagnostic Procedure in the Diagnosis section to correct the problem. If the on-board diagnostics are working properly, the next step is:

2. Is there a DTC stored? If a DTC is stored, go directly to the number DTC procedure in the Diagnosis section. This will determine if the fault is still present.

Figure 1-1 - Marine Data Link Connector (DLC)

a hand-held diagnostic scanner, plugged into the DLC. Once the DTC tool has been connected, and “service

mode” or “ON” selected, the ignition switch must be mov ed to the key “ON,” engine “OFF” position. At this point, the MIL should ﬂ ash DTC 12 two times consecutively. This would be the following flash sequence: “flash, pause, ﬂ ash-ﬂ ash, long pause, ﬂ ash, pause, ﬂ ash-ﬂ ash.” DTC 12 indicates that the ECM’s diagnostic system is operating. If DTC 12 is not indicated, a problem is present within the diagnostic system itself, and should be addressed by consulting the “On-Board Diagnostic (OBD) System Check” in the Diagnosis section.

Following the output of DTC 12, the MIL will indicate a DTC two times if a DTC is present, or it will continue to ﬂ ash DTC 12. If more than one DTC has been stored in the ECM’s memory, the DTC’s will be ﬂ ashed out from the lowest to the highest, with each DTC being ﬂ ashed two

DLC Scan Tools

The ECM can communicate a variety of information through the DLC. This data is transmitted at a high frequency which requires a scan tool for interpretation.

With an understanding of the data which the scan tool displays, and knowledge of the circuits involved, the scan tool can be very useful in obtaining information which would be more difﬁ cult or impossible to obtain with other equipment.

A scan tool does not make the use of Diagnostic Procedures unnecessary, nor do they indicate exactly where the problem is in a particular circuit. Some Diagnostic Procedures incorporate steps with the use of a scan tool (scan diagnostics), or with the DTC tool (non-scan diagnostics).

MEFI 4 - PCM

1 - 4 General Information 5.0/5.7/6.0/8.1L Scan Tool Use With Intermittents

The scan tool provides the ability to perform a “wiggle test” on wiring harnesses or components with the engine not running, while observing the scan tool display.

The scan tool can be plugged in and observed while driving the boat under the condition when the MIL turns “ON” momentarily, or when the engine driveability is momentarily poor. If the problem seems to be related to certain parameters that can be checked on the scan tool, they should be checked while driving the boat. If there does not seem to be any correlation between the problem and any speciﬁ c circuit, the scan tool can be checked on each position, watching for a period of time to see if there is any change in the readings that indicates intermittent operation.

The scan tool is also an easy way to compare the operating parameters of a poorly operating engine with those of a known good one. For example, a sensor may shift in value but not set a DTC.

The scan tool has the ability to save time in diagnosis and prevent the replacement of good parts. The key to using the scan tool successfully for diagnosis lies in the technicians ability to understand the system they are trying to diagnose, as well as an understanding of the scan tool operation and limitations. The technician should read the tool manufacturer’s operating manual to become familiar with the tool’s operation.

How Diagnostic Trouble Codes (DTC) Are Set

The ECM is programmed to receive calibrated voltage signals from the sensors. The voltage signal from the sensor may range from as low as 0.1 volt to as high as 4.9 volts. The sensor voltage signal is calibrated for engine application. This would be the sensor’s operating parameter or “window.” The ECM and sensors will be discussed further in the ECM and Sensor section.

If a sensor is within its operating or acceptable parameters (Figure 1-2), the ECM does not detect a problem. When a sensor voltage signal falls out of this “window,” the ECM no longer receives a signal voltage within the operating “window.” When the ECM does not receive the “window” voltage for a calibratible length of time, a DTC will be stored. The MIL will be illuminated and a known default value will replace the sensor value to restore engine performance.

Clearing Diagnostic Trouble Codes (NonScan)

1. Install Diagnostic Trouble Code (DTC) tool.

2. Ignition “ON,” engine “OFF.”

3. Switch DTC tool to “service mode” or “ON.”

4. Move the throttle from 0% (idle) to 100% (WOT) and

5. Switch DTC tool to “normal mode” or “OFF.” (If this

6. Turn ignition “OFF” for at least 20 seconds.

7. Ignition “ON,” engine “OFF.”

8. Switch DTC tool to “service mode” or “ON” and verify

9. If original DTC(s) are still present, check “Notice” below

10. If new DTC(s) are displayed, perform the OBD system

NOTICE: When clearing DTC’ s with or without the use of a scan tool, the ignition must be cycled to the “OFF” position or the DTC’s will not clear.

5 VOLTS

XXXXXXXXXXXXXXX DEFAULTXXXXXXXXXXX

4.6V

V O L T A G E

XXXXXXXXXXXXXXX DEFAULTXXXXXXXXXXX

0 VOLTS

Figure 1-2 - Example of Sensor Normal Operation

TYPICAL SENSOR RANGE

“WINDOW”

0.7V

6-5-93

back to 0%.

step is not performed, the engine may not start and run).

DTC 12 only. Remove DTC tool.

and repeat the DTC clearing procedure.

check.

MEFI 4 - PCM

5.0/5.7/6.0L/8.1L General Information 1 - 5 Clearing Diagnostic Trouble Codes (Scan)

1. Install scan tool.

2. Start engine.

3. Select “clear DTC’s” function.

4. Clear DTC’s.

5. Turn ignition “OFF” for at least 20 seconds.

6. Turn ignition “ON” and read DTC’s. If DTC’s are still present, check “Notice” below and repeat procedure following from step 2.

NOTICE: When clearing DTC’ s with or without the use of a scan tool, the ignition must be cycled to the “OFF” position or the DTC’s will not clear.

Non-Scan Diagnosis Of Driveability Concerns (No DTC’s Set)

If a driveability concern still exists after following the OBD system check and reviewing the Symptoms section, an out of range sensor may be suspected. Because of the unique design of the MEFI system, the ECM will replace sensed values with calibrated default values in the case of a sensor or circuit malfunction. By allowing this to occur, limited engine performance is restored until the boat is repaired. A basic understanding of sensor operation is necessary to be able to diagnose an out of range sensor.

If the sensor is out of range, but still within the operating “window” of the ECM, the prob lem will go undetected by the ECM and may result in a driveability concern.

A good example of this would be if the coolant sensor was reading incorrectly and indicating to the ECM that coolant temperature was at 50°F, but actual coolant temperature was at 150°F (Figure 1-3). This would cause the ECM to deliver more fuel than what was actually needed by the engine. This resulted in an overly rich condition, causing rough running. This condition would not have caused a DTC to set, as the ECM interprets this as within the operating “window.”

To identify a sensor that is out of range, you may unplug the sensor electrical connector while the engine is running. After about 2 minutes, the DTC for that sensor will set, illuminate the MIL, and replace the sensed value with a calibrated default value. If at that point, a noticeable performance increase is observed, the non-scan DTC table for that particular sensor may be followed to correct the problem.

NOTICE: Be sure to clear each DTC after disconnecting and reconnecting each sensor. Failure to do so may result in a misdiagnosis of the driveability concern.

Aftermarket (Add-On) Electrical And Vacuum Equipment

Aftermarket, add-on electrical and vacuum equipment is deﬁ ned as any equipment installed on a vehicle after leaving the factory that connects to the vehicles electrical or vacuum systems.

Notice: Do not attach add-on vacuum operated equipment to this engine. The use of add-on vacuum equipment may result in damage to engine components or systems.

Notice: Connect any add-on electrically operated equipment to the vehicle’s electrical system at the battery (power and ground) in order to prevent damage to the vehicle.

Add-on electrical equipment, even when installed to these strict guidelines, may still cause the powertrain system to malfunction. This may also include equipment not connected to the vehicle’s electrical system such as portable telephones and radios. Therefore, the ﬁ rst step in diagnosing any powertrain problem, is to eliminate all aftermarket electrical equipment from the vehicle. After this is done, if the problem still exists, diagnose the problem in the normal manner.

Use of Circuit Testing Tools

Do not use a test lamp in order to diagnose the engine electrical systems unless speciﬁ cally instructed by the diagnostic procedures. Use the J 35616-A connector test adapter kit whenever diagnostic procedures call for probing any connectors.

LOW TEMP - 5 VOLTS

XXXXXXXXXXXXXXX DEFAULTXXXXXXXXXXX

T

------50 -4.2V OUT OF RANGE SENSOR

E M P E R A

T U R E

------150 -1.7V ACTUAL COOLANT TEMPERATURE

XXXXXXXXXXXXXXX DEFAULTXXXXXXXXXXX

HIGH TEMP - 0 VOLTS

Figure 1-3 - Example of Shifted Sensor Operation

6-5-93

MS 13552

Tools Needed To Service The System

Refer to Special Tools in this section for engine control tools for servicing the system.

MEFI 4 - PCM

1 - 6 General Information 5.0/5.7/6.0/8.1L Service Precautions

The following requirements must be observed when working on MEFI equipped engines.

1. Before removing any ECM system component, disconnect the negative battery cable.

2. Nev er start the engine without the battery being solidly connected.

3. Never separate the battery from the on-board electrical system while the engine is running.

4. Never separate the battery feed wire from the charging system while the engine is running.

5. When charging the battery, disconnect it from the vehicle’s electrical system.

6. Ensure that all cable harnesses are connected solidly and the battery connections are thoroughly clean.

7. Never connect or disconnect the wiring harness at the ECM when the ignition is switched “ON.”

8. Before attempting any electric arc welding on the vehicle, disconnect the battery leads and the ECM connector(s).

9. When steam cleaning engines, do not direct the nozzle at any ECM system components. If this happens, corrosion of the terminals or damage of components can take place.

10. Use only the test equipment speciﬁ ed in the diagnostic procedures, since other test equipment may either giv e incorrect test results or damage good components.

11. All measurements using a multimeter must use a digital meter with a rating of 10 megaohm input impedance.

12. When a test light is speciﬁ ed, a “low-power” test light must be used. Do not use a high-wattage test light. While a particular brand of test light is not suggested, a simple test on any test light will ensure it to be safe for system circuit testing (Figure 1-4). Connect an accurate ammeter (such as the high-impedance digital multimeter) in series with the test light being tested, and power the test light ammeter circuit with the vehicle battery.

DC Amps

If the ammeter indicates the testlight is If the ammeter indicates the testlight is

safe

to use.

not safe

less

than 3/10 amp(.3A) current flow,

more

than 3/10 amp(.3A) current flow,

to use.

Figure 1-4 - Test Light Amperage Draw Test

testlight

*

+

BATTERY

-

I 22307

MEFI 4 - PCM

5.0/5.7/6.0L/8.1L General Information 1 - 7 Special Tools (1 of 3)

VOLTMETER - Voltage position measures magnitude of

voltage when connected in parallel to an existing circuit. A digital voltmeter with a 10 megohm input impedance is used because this type of meter will not load down the circuit and result in faulty readings. Some circuits require accurate low voltage readings because they have a very high resistance.

AMMETER - When used as an ammeter, this meter accurately measures extremely low current ﬂ ow. Refer to meter instructions for more information.

AUTO 100

OFF

0

1234

ms

TRUE RMS MULTIMETER

87

RECORD MAX MIN AVG

5678 90

~

V

_

…

V

…

mV

AC DC

µ

m V A n F S % M k Ω Hz

4000 mV

_

(

Ω

• Selector must be set properly for both function and

_

mA

…

~

A

_

…

µ

A

~

range. DC is used for most measurements.

OHMMETER - Measures resistance of circuit directly in ohms. Refer to meter instructions for more information.

• OL display in all ranges indicates open circuit.

• Zero display in all ranges indicates a short circuit.

400mA MAX

FUSED

10A MAX FUSED

• An intermittent connection in a circuit may be indicated

by a digital reading that will not stabilize on the circuit.

• Range Switch - Automatic and Manual.

200ý - Reads ohms directly 2K, 20K, 200Ký - Reads ohms in thousands

J 39978

2M, 20M, 200Mý - Reads ohms in millions

3

➤

2

1

0

TACHOMETER

VACUUM PUMP WITH GAUGE (20 IN. HG. MINIMUM)

Use the gauge to monitor manifold engine vacuum and use the hand pump to check vacuum sensors, solenoids and valves.

J 23738-A

UNPOWERED TEST LIGHT

Used for checking wiring for a complete circuit, voltages and grounds.

J 34142-B

TACHOMETER

4

5

Must have inductive trigger signal pick-up.

NS 14574

MEFI 4 - PCM

1 - 8 General Information 5.0/5.7/6.0/8.1L

Special Tools (2 of 3)

METRI-PACK TERMINAL REMOVER

Used for removing 150 series Metri-Pack “pull-to-seat” terminals from connectors. Refer to wiring harness service in MEFI General Information Section for removal procedure.

J 35689

WEATHER PACK TERMINAL REMOVER

Used for removing terminals from Weather P ack connectors. Refer to wiring harness service in MEFI General Information Section for removal procedure.

J 28741-A/BT-8234-A

DIAGNOSTIC TROUBLE CODE (DTC) TOOL

A hand held diagnostic tool that plugs into the DLC connector for various diagnostics.

TA 06075

RTK0078

J 34730-2C & J 34730-350/BT 8329

RT0086

FUEL PRESSURE GAUGE

Used for checking fuel system pressure on MFI and PFI engines.

INJECTOR HARNESS TEST LIGHT

A specially designed light used to visually indicate injector electrical pulses from the ECM.

DIACOM SCAN TOOL

A hand held diagnostic tool that plugs into the DLC connector for various diagnostics. It will display various parameters.

MEFI 4 - PCM

5.0/5.7/6.0L/8.1L General Information 1 - 9 Special Tools (3 of 3)

HARNESS TEST ADAPTER KIT

Used to make electrical test connections in current W eather Pack, Metri-Pack and Micro-Pack style terminals.

J 35616

20’ DIAGNOSTIC CONNECTOR EXTENSION CABLE

Extension cable to go between the scan tool and the DLC on the engine harness.

TA 06076

FUEL LINE QUICK-CONNECT SEPARATOR

Used to release fuel line quick-connect ﬁ ttings.

J-39021

J 37088-A/BT-9171

INJECTOR TESTER

Separately energizes each injector to compare for equal fuel pressure drops over a constant time interval.

+

INJECTOR

VOLTS

-

LOWBATTERY

READYTO TEST

MP

TESTIN PROGRESS

AMP

4AMP

2.5 AMP

PUSHTO TEST

6.5 AMP

KENT-MOORE

J 39021

TIMING LIGHT

Must have inductive signal pickup.

J 34186

MEFI 4 - PCM

1 - 10 General Information 5.0/5.7/6.0/8.1L

ABBREVIATIONS

BARO - BAROMETRIC PRESSURE BAT - BATTERY, BATTERY POSITIVE

TERMINAL, BATTERY OR SYSTEM VOLTAGE

B+ - BATTERY POSITIVE CKP - CRANKSHAFT POSITION SENSOR CKT - CIRCUIT CMP - CAMSHAFT POSITION SENSOR CONN - CONNECTOR CYL - CYLINDER DEG - DEGREES DIAG - DIAGNOSTIC DLC - DATA LINK CONNECTOR DMM - DIGITAL MULTIMETER DTC - DIAGNOSTIC TROUBLE CODE ECM - ENGINE CONTROL MODULE ECT - ENGINE COOLANT TEMPERATURE

SENSOR EEPROM - ELECTRONIC ERASABLE

PROGRAMMABLE READ ONLY MEMORY

EI - ELECTRONIC IGNITION EMI - ELECTROMAGNETIC

INTERFERENCE ENG - ENGINE GND - GROUND GPH - GALLONS PER HOUR HVS - HIGH-VOLTAGE SWITCH IAC - IDLE AIR CONTROL IAT - INTAKE AIR TEMPERATURE IC - IGNITION CONTROL

KS - KNOCK SENSOR SYSTEM KV - KILOVOLTS MAP - MANIFOLD ABSOLUTE PRESSURE MEFI - MARINE ELECTRONIC FUEL

INJECTION MFI - MULTIPORT FUEL INJECTION MIL - MALFUNCTION INDICATOR LAMP MSEC - MILLSECOND N/C - NORMALLY CLOSED N/O - NORMALLY OPEN OBD - ON-BOARD DIAGNOSTIC SYSTEM

CHECK OPT - OPTIONAL PFI - PORT FUEL INJECTION PROM - PROGRAMMABLE READ ONLY

MEMORY RAM - RANDOM ACESS MEMORY REF HI - REFERENCE HIGH REF LO - REFERENCE LOW ROM - READ ONLY MEMORY SLV - SLAVE SW - SWITCH TACH - TACHOMETER TBI - THROTTLE BODY INJECTION TERM - TERMINAL TP - THROTTLE POSITION SENSOR V - VOLTS VAC - VACUUM WOT - WIDE OPEN THROTTLE “ HG - INCHES OF MERCURY

IGN - IGNITION INJ - INJECTOR I/O - INPUT/OUTPUT kPa - KILOPASCAL

MEFI 4 - PCM

5.0/5.7/6.0L/8.1L General Information 1 - 11

T endency f or connectors to come apart due to vibration

Diagnosis

The diagnostic tables and functional checks in this manual are designed to locate a faulty circuit or component through logic based on the process of elimination. The tables are prepared with the requirement that the system functioned correctly at the time of assembly and that there are no multiple failures.

Engine control circuits contain many special design features not found in standard vehicle wiring. Environmental protection is used extensively to protect electrical contacts. Proper splicing methods must be used when necessary.

The proper operation of low amperage input/output circuits depend upon good continuity between circuit connectors. It is important before component replacement and/or during normal troubleshooting procedures that a visual inspection of any questionable mating connector is performed. Mating surfaces should be properly formed, clean and likely to make proper contact. Some typical causes of connector problems are listed below:

Improperly formed contacts and/or connector

•

housing.

Damaged contacts or housing due to improper

•

engagement.

Corrosion, sealer or other contaminants on the contact

•

mating surfaces.

Incomplete mating of the connector halves during

•

initial assembly or during subsequent troubleshooting procedures.

•

and/or temperature cycling.

Terminals not fully seated in the connector body.

•

Inadequate terminal crimps to the wire.

•

On-Board Service

Wiring Harness Service

Figure 1-5

Wiring harnesses should be replaced with proper part number harnesses. When wires are spliced into a harness, use the same gauge wire with high temperature insulation only.

With the low current and voltage levels found in the system, it is important that the best possible bond be made at all wire splices by soldering the splices as shown in Figure 1-5.

Use care when probing a connector or replacing a connector terminal. It is possible to short between opposite terminals. If this happens, certain components can be damaged. Always use jumper wires with the corresponding mating terminals between connectors for circuit checking. NEVER probe through connector seals, wire insulation, secondary ignition wires, boots, nipples or covers. Microscopic damage or holes may result in water intrusion, corrosion and/or component failure.

DRAIN WIRE

OUTER JACKET

MYLAR

1REMOVE OUTER JACKET. 2UNWRAP ALUMINUM/MYLAR TAPE. DO NOT

 REMOVE MYLAR.

3UNTWIST CONDUCTORS. STRIP INSULATION AS  NECESSARY.

DRAIN WIRE

4SPLICE WIRES USING SPLICE CLIPS AND ROSIN CORE  SOLDER. WRAP EACH SPLICE TO INSULATE.

5WRAP WITH MYLAR AND DRAIN (UNINSULATED) WIRE.

6TAPE OVER WHOLE BUNDLE TO SECURE AS BEFORE.

1LOCATE DAMAGED WIRE. 2REMOVE INSULATION AS REQUIRED.

3SPLICE TWO WIRES TOGETHER USING SPLICE  CLIPS AND ROSIN CORE SOLDER.

4COVER SPLICE WITH TAPE T O INSULA TE  FROM OTHER WIRES.

5RETWIST AS BEFORE AND TAPE WITH  ELECTRICAL TAPE AND HOLD IN PLACE.

8-24-94 RS 22186

Figure 1-5 - Wiring Harness Repair

MEFI 4 - PCM

1 - 12 General Information 5.0/5.7/6.0/8.1L Wiring Connector Service

Most connectors in the engine compartment are protected against moisture and dirt which could create oxidation and deposits on the terminals. This protection is important because of the very low voltage and current levels found in the electronic system. The connectors have a lock which secures the male and female terminals together. A secondary lock holds the seal and terminal into the connector.

When diagnosing, open circuits are often difﬁ cult to locate by sight because oxidation or terminal misalignment are hidden by the connectors. Merely wiggling a connector on a sensor, or in the wiring harness, may locate the open circuit condition. This should always be considered when an open circuit or failed sensors is indicated. Intermittent problems may also be caused by oxidized or loose connections.

Before making a connector repair, be certain of the type of connector. Some connectors look similar but are serviced differently.

Metri-Pack Series 150 Terminals

Figure 1-6

Some ECM harness connectors contain terminals called Metri-Pack (Figure 1-6). These are used at some of the sensors and the distributor connector.

Metri-Pack terminals are also called “Pull-To-Seat” terminals because, to install a terminal on a wire, the wire is ﬁ rst inserted through the seal and connector. The terminal is then crimped on the wire, and the terminal is pulled back into the connector to seat it in place.

To remove a terminal:

1. Slide the seal back on the wire.

2. Insert tool J 35689 or equivalent, as shown in Figure 1-6, to release the terminal locking tang.

3. Push the wire and terminal out through the connector. If the terminal is being reused, reshape the locking tang.

AB

1

5

3

1. METRI-PACK SERIES 150 FEMALE TERMINAL.

2. LOCKING T ANG.

RS 22187

2

Figure 1-6 - Metri-Pack Series 150 Terminal Removal

4

3. TOOL J35689 OR BT-8446.

4. CONNECTOR BODY.

5. SEAL.

1

2

MEFI 4 - PCM

5.0/5.7/6.0L/8.1L General Information 1 - 13

Weather-Pack Connectors

Figure 1-7

Figure 1-7 shows a Weather-Pack connector and the tool (J 28742 or equivalent) required to service it. This tool is used to remove the pin and sleeve terminals. If terminal removal is attempted without using the special tool required, there is a good chance that the terminal will be bent or deformed, and unlike standard blade type terminals, these terminals cannot be straightened once they are bent.

Make certain that the connectors are properly seated and all of the sealing rings in place when connecting leads. The hinge-type ﬂ ap provides a secondary locking feature for the connector. It improves the connector reliability by retaining the terminals if the small terminal lock tangs are not positioned properly. Weather-Pack connections cannot be replaced with standard connections.

MALE CONNECTOR BODY

1. OPEN SECONDARY LOCK HINGE ON CONNECTOR

2. REMOVE TERMINAL USING TOOL

TERMINAL REMOVAL TOOL J 28742, J 38125-10 OR BT-8234-A

3. CUT WIRE IMMEDIATELY BEHIND CABLE SEAL

SEAL

FEMALE CONNECTOR BODY

PUSH TO RELEASE

WIRE

4. REPLACE TERMINAL A. SLIP NEW SEAL ONTO WIRE B. STRIP 5mm (.2") OF INSULATION FROM WIRE C. CRIMP TERMINAL OVER WIRE AND SEAL

SEAL

5. PUSH TERMINAL INTO CONNECTOR UNTIL LOCKING TANGS ENGAGE

6. CLOSE SECONDARY LOCK HINGE

RS 22188

Figure 1-7 - Weather-Pack Terminal Repair

MEFI 4 - PCM

1 - 14 General Information 5.0/5.7/6.0/8.1L

Micro-Pack 100/W Series Connectors

Figure 1-8

The harness connectors used with the ECM “J1” and “J2” connectors are Micro-Pack 100/W Series. It is used for its ruggedized construction, capable of carrying more current and provides good sealing ability. The connector is made up of ﬁ ve different parts (refer to Figure 1-8 View A): Str ain Relief (1), Seal (2), Connector (3), Index Cover (4) and Ter minals (not shown).

Remove or Disconnect

1. Negative battery cable.

2. Connector from ECM by lifting up locking tab with thumb and pulling on connector body.

Inspect

Check strain relief for being cracked or locking tab

•

damaged.

Check index cover for being cracked.

•

Check seal for being torn, twisted or out of shape from

•

improper installation.

Check terminals for being corroded, out of position,

•

bent or stretched out.

Use a wire gauge .038 for checking terminal

–

internal ﬁ t. Wire gauge should slide with smooth feel and not be loose.

Notice: If you are only going to clean terminals, complete disassembly is not necessary. Remove index cover from the connector by pushing on Tab C on both sides and sliding off cover. Care m ust be tak en not to mov e terminals out of their position. The index cover locks the terminals in position. If repair or replacement of parts is needed, DO NOT remove index cover at this time.

3. With a small screwdriver, move Tabs A on strain relief (1) to unlock position.

4. Open strain relief as shown in View B.

5. Release Tabs B (View C) on connector (3) by pushing inward with both thumbs or small screwdriver.

6. Push Tabs B through strain relief (1) with thumbs or small screwdriver while in released position.

Important

Where there are not wires in strain relief, small plugs

•

are installed. DO NO T lose the plugs, they are important to help keep connector assembly sealed.

7. Remove plugs where there are not any wires.

8. Slide strain relief off of seal and back on wires.

9. Slide seal off of connector and back on wires.

Important

To ensure proper engine operation after repair of

•

connector assembly , wires must be in proper connector location. Before removing index cover, note if there are any wires of the same color. Mark these wires from the location that they were remov ed. For the remaining wires, their location can be found by ref erring to “Wiring Diagrams” in the Diagnosis section. The strain relief is numbered for identifying wire location.

10. Index cover (4) by pushing in on Tabs C with a small screwdriver.

11. Ter minals by pulling out of connector.

12. Seal (2) from wires.

13. Strain relief (1) from wires.

Clean and Inspect

Terminals for corrosion.

•

– Use spray electrical contact cleaner.

Loose crimps on terminals.

•

Broken wires at terminals.

•

Notice: For terminal replacement, refer to instructions found with terminal repair kit and crimper tool.

Install or Connect

1. Align index cover (4) on connector (3) and lock into position. Make sure Tabs C are locked.

2. Align seal (2) on connector (3) and slide all the way on.

DO NOT install strain relief (1) onto connector (3)

•

yet.

3. One wire with terminal installed, through strain relief (1) in location that it was removed.

Start with the lowest numbered wire position for

•

that connector.

4. Terminal through seal (2), connector (3) and into inde x cover (4) until it locks in place.

5. Remaining wires one at a time per same method.

• Keep wires straight.

DO NOT kink wires.

•

6. Strain relief (1) onto seal (2) and connector (3).

7. Lock Tabs B into strain relief (1).

8. Plugs into strain relief (1) where there are not any wires.

9. Fold strain relief (1) together and lock Tabs A.

10. Connector assembly to ECM.

11. Negative battery cable.

MEFI 4 - PCM

5.0/5.7/6.0L/8.1L General Information 1 - 15

1

2

TAB B

TAB C

34

FIGURE A - EXPLODED VIEW OF CONNECTOR ASSEMBLY

1 STRAIN RELIEF 2 SEAL

TAB A

FIGURE B - STRAIN RELIEF CLOSED

TAB B

3 CONNECTOR 4 INDEX COVER

TAB A

21 3 4 5 6 7 8 9 10111213141516

1817 1920212223242526272829303132

TAB A

TAB B

FIGURE C - STRAIN RELIEF OPENED

PS 19745

Figure 1-8 - Micro-Pack 100/W Series

MEFI 4 - PCM

1 - 16 General Information 5.0/5.7/6.0/8.1L

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intentionally

blank

MEFI 4 - PCM

5.0/5.7/6.0L/8.1L ECM and Sensors 2 - 1

Marine Electronic Fuel Injection (MEFI) Section 2 Engine Control Module (ECM) and Sensors

This section will describe the function of the Engine Control Module (ECM) and the sensors. The section explains how voltages reflect the inputs and outputs of the ECM. The sensors are described how they operate and how to replace them.

Contents

General Description .............................................Page 2

Computers and Voltage Signals.......................Page 2

Analog Signals.................................................Page 2

Three-Wire Sensors ..................................Page 2

Two-Wire Sensors .....................................Page 2

Digital Signals..................................................Page 3

Switch Types..............................................Page 3

Pulse Counters..........................................Page 3

Engine Control Module (ECM).........................Page 4

ECM Function............................................Page 4

Memory .....................................................Page 4

ROM..........................................................Page 4

RAM...........................................................Page 4

EEPROM...................................................Page 4

Speed Density System ....................................Page 5

Speed........................................................Page 5

Density.......................................................Page 5

ECM Inputs and Sensor Descriptions..............Page 5

Input Components............................................Page 5

Output Components.........................................Page 5

MEFI Inputs and Outputs ..........................Page 6

Engine Coolant Temperature (ECT)

Sensor.......................................................Page 7

Manifold Absolute Pressure (MAP)

Sensor.......................................................Page 7

Throttle Position (TP) Sensor....................Page 8

Intake Air Temperature (IAT) Sensor.........Page 8

Ignition Control (IC) Reference..................Page 8

Knock Sensor............................................Page 9

Discrete Switch Inputs...............................Page 9

Diagnosis ............................................................Page 10

Engine Control Module (ECM).......................Page 10

On-Board Service ...............................................Page 10

Engine Control Module (ECM)

Replacement..................................................Page 10

System Relay.................................................Page 11

Fuel Pump Relay ...........................................Page 11

Starter Relay..................................................Page 11

Engine Coolant Temperature (ECT)

Sensor............................................................Page 12

Manifold Absolute Pressure (MAP)/Intake Air

Temperature (IAT) Sensor (5.0/5.7L).............Page 13

Manifold Absolute Pressure (MAP)

Sensor (6.0/8.1L)...........................................Page 14

Throttle Position (TP) Sensor.........................Page 16

Idle Air Control (IAC) Valve............................Page 17

Knock Sensor (KS) (5.0/5.7L)........................Page 18

Knock Sensors (KS) (6.0L)............................Page 18

Torque Speciﬁ cations ........................................Page 20

MEFI 4 - PCM

2 - 2 ECM and Sensors 5.0/5.7/6.0/8.1L

General Description

The Marine Electronic Fuel Injection (MEFI) system is equipped with a computer that provides the operator with state-of-the-art control of fuel and spark delivery. Before we discuss the computers on the Marine applications, let’s discuss how computers use voltage to send and receive information.

Computers and Voltage Signals

Voltage is electrical pressure. Voltage does not flow through circuits. Instead, voltage causes current. Current does the real work in electrical circuits. It is current, the ﬂ ow of electrically charged particles, that energizes solenoids, closes relays and illuminates lamps.

Besides causing current ﬂ ow in circuits, voltage can be used as a signal. Voltage signals can send information by changing levels, changing waveform (shape) or changing the speed (frequency( at which the signal switches from one level to another. Computers use voltage signals to communicate with one another. The different circuits inside computers also use voltage signals to talk to each other.

There are two kinds of voltage signals, analog and digital. Both of these are used in computer systems. It is important to understand the difference between them and the different ways they are used.

Analog Signals

An analog signal is continuously variable. This means that the signal can be any voltage within a certain range.

An analog signal usually gives information about a condition that changes continuously over a certain range. For example, in a marine engine, temperature is usually provided by an analog signal. There are two general types of sensors that produce analog signals, the 3-wire and the 2-wire sensors.

Three-Wire Sensors

Figure 2-1 shows a schematic representation of a 3-wire sensor. All 3-wire sensors have a reference voltage, a ground and a variable “wiper.” The lead coming off of the “wiper” will be the signal to the Engine Control Module (ECM). As this “wiper” position changes, the signal voltage to the ECM also changes.

ECM

TYPICAL SENSOR

Figure 2-1 - Three-Wire Sensors

VOLTAGE OUT

SIGNAL INPUT

4-24-91

MS 11697

Two-Wire Sensors

Figure 2-2 shows a schematic representation of a 2-wire sensor. This sensor is basically a variable resistor in series with a known-ﬁ xed resistor within the ECM. By knowing the values of the input voltage and the v oltage drop across the known resistor, the value of the variable resistor can be determined. The variable resistors that are commonly used are called thermistors. A thermistor’s resistance varies with temperature.

ECM

TYPICAL SENSOR

SENSOR SIGNAL

5V

MEFI 4 - PCM

SENSOR GROUND

4-24-91

MS 11698

Figure 2-2 - Two-Wire Sensors

5.0/5.7/6.0L/8.1L ECM and Sensors 2 - 3

Digital Signals

Digital signals are also variable, but not continuously. They can only be represented by distinct voltages within a range . For example, 1V, 2V or 3V would be allowed, but 1.27V or

2.56V would not. Digital signals are especially useful when the information can only refer to two conditions: “YES” and “NO,” “ON” and “OFF” or “HIGH” and “LOW.” This would be called a digital binary signal. A digital binary signal is limited to two voltage lev els . One lev el is a positiv e voltage , the other is no voltage (zero volts). As y ou can see in Figure 2-3, a digital binary signal is a square wave.

The ECM uses digital signals in a code that contains only ones and zeros. The high voltage of the digital signal represents a one (1), and no voltage represents a zero (0). Each “zero” and each “one” is called a bit of information, or just a “bit.” Eight bits together are called a “word.” A word, therefore, contains some combination of eight binary code bits.

Binary code is used inside the ECM and between a computer and any electronic device that understands the code. By stringing together thousands of bits, computers can communicate and store an inﬁ nite varieties of information. To a computer that understands binar y, 11001011 might mean that it should turn an output device “ON” at slow speed. Although the ECM uses 8-bit digital codes internally and when talking to another computer, each bit can have a meaning.

Switch T ypes

Switched inputs (also known as discretes) to the ECM can cause one bit to change, resulting in information being communicated to the ECM. Switched inputs can come in two types: “pull-up” and “pull-down” types. Both types will be discussed.

With “pull-up” type switch, the ECM will sense a voltage when the switch is CLOSED. With “pull-down” type switch, the ECM will sense a voltage when the switch is OPEN.

Pulse Counters

For the ECM to determine frequency information from a switched input, the ECM must measure the time between the voltage pulses. As a number of pulses are recorded in a set amount of time, the ECM can calculate the frequency. The meaning of the frequency number can have any number of meanings to the ECM.

An example of a pulse counter type of input is the Crankshaft Position (CKP) sensor input. The ECM can count a train of pulses, a given number of pulses per engine revolution. In this way, the ECM can determine the RPM of the engine.

V O L T A G E

DIGITAL BINARY SIGNAL

TIME

4-18-91

MS 11696

Figure 2-3 - Digital Voltage Signal

MEFI 4 - PCM

2 - 4 ECM and Sensors 5.0/5.7/6.0/8.1L

Engine Control Module (ECM)

The Engine Control Module (ECM), located on the engine, is the control center of the fuel injection system. It controls the following:

• Fuel control circuit

• Ignition control circuit

• Idle Air Control (IAC)

• Knock Sensor (KS) system

• On-board diagnostics for engine functions

It constantly looks at the information from various sensors, and controls the systems that affect engine performance. The ECM also performs the diagnostic function of the system. It can recognize operational problems, alert the operator through the MIL (Malfunction Indicator Lamp) and store diagnostic trouble codes, or logged warnings, which identify the problem areas to aid the technician in making repairs. Refer to General Information section for more information on using the diagnostic function of the ECM.

ECM Function

The ECM supplies either 5 or 12 volts to power various sensors or switches. This is done through resistances in the ECM which are so high in value that a test light will not light when connected to the circuit. In some cases, even an ordinary shop voltmeter will not give an accurate reading because its resistance is too low. Therefore, a digital voltmeter with at least 10 megohms input impedance is required to ensure accurate voltage readings. Tool J 39978 meets this requirement.

The ECM controls output circuits such as the injectors, IAC, relays, etc. by controlling the ground or power feed circuit.

Memory

There are three types of memory storage within the ECM. They are ROM, RAM and EEPROM.

ROM

Read Only Memory (ROM) is a permanent memory that is physically soldered to the circuit boards within the ECM. The ROM contains the overall control programs. Once the ROM is programmed, it cannot be changed. The ROM memory is non-erasable, and does not need power to be retained.

RAM

Random Access Memory (RAM) is the microprocessor “scratch pad.” The processor can write into, or read from this memory as needed. This memory is erasable and needs a constant supply of voltage to be retained. If the voltage is lost, the memory is lost.

EEPROM

The Electronically Erasable Programmable Read Only Memory (EEPROM) is a permanent memory that is physically soldered within the ECM. The EEPROM contains program and calibration information that the ECM needs to control engine operation.

The EEPROM is not replaceable. If the ECM is replaced, the new ECM will need to be programmed by the engine manufacturer with the calibration inf ormation that is speciﬁ c to each marine application.

MEFI 4 - PCM

J2J1

MEFI3004

Figure 2-4 - Engine Control Module (ECM)

5.0/5.7/6.0L/8.1L ECM and Sensors 2 - 5

Speed Density System

The Marine Electronic Fuel Injection (MEFI) system is a speed and air density system. The system is based on “speed density” fuel management.

Sensors provide the ECM with the basic information for the fuel management portion of its operation. Signals to the ECM establish the engine speed and air density factors.

Speed

The engine speed signal comes from the CKP sensor to the ECM. The ECM uses this information to determine the “speed” or RPM factor for fuel and spark management.

Density

One particular sensor contributes to the density factor, the Manifold Absolute Pressure (MAP) sensor. The MAP sensor is a 3-wire sensor that monitors the changes in intake manifold pressure which results from changes in engine loads. These pressure changes are supplied to the ECM in the form of electrical signals.

As intake manifold pressure increases, the vacuum decreases. The air density in the intake manifold also increases, and additional fuel is needed.

The MAP sensor sends this pressure information to the ECM, and the ECM increases the amount of fuel injected, by increasing the injector pulse width. As manifold pressure decreases, the vacuum increases, and the amount of fuel is decreased.

These two inputs, MAP and RPM, are the major determinants of the air/fuel mixture delivered by the fuel injection system. The remaining sensors and switches provide electrical inputs to the ECM, which are used for modiﬁ cation of the air/fuel mixture, as well as for other ECM control functions, such as idle control.

ECM Inputs and Sensor Descriptions

Figure 2-5 lists the data sensors, switches, and other inputs used by the ECM to control its various systems. Although we will not cover them all in great detail, there will be a brief description of each.

Input Components

The ECM monitors the input components for circuit continuity and out-of-range values. This includes performance checking. Performance checking refers to indicating a fault when the signal from a sensor does not seem reasonable, such as a throttle position (TP) sensor that indicates high throttle position at low engine loads or MAP voltage. The input components may include, but are not limited to, the following sensors:

• Intake air temperature (IAT) sensor (5.0/5.7L only)

• Crankshaft position (CKP) sensor

• Camshaft position (CMP) sensor

• Knock sensor(s) (KS)

• Throttle position (TP) sensor

• Engine coolant temperature (ECT) sensor

• Manifold absolute pressure (MAP) sensor

Output Components

Diagnose the output components for the proper response to ECM commands. Components where functional monitoring is not feasible, will be monitored for circuit continuity and out-of-range values, if applicable.

Output components to be monitored include, but are not limited to, the following circuits:

• The malfunction indicator lamp (MIL) control

• The check gauges lamp control

• The general warning 2 (low oil pressure) lamp control

MEFI 4 - PCM

2 - 6 ECM and Sensors 5.0/5.7/6.0/8.1L

MEFI INPUTS AND OUTPUTS

INPUTS

BATTERY 12V

IGNITION 12V

CRANKSHAFT POSITION SENSOR (RPM)

CAMSHAFT POSITION SENSOR

THROTTLE POSITION (TP) SENSOR

MANIFOLD ABSOLUTE PRESSURE(MAP)

(TYPICAL)

E

L E C T R

O N

I

C

OUTPUTS

FUEL INJECTORS

MULTIPLE IGNITION CONTROLS (IC)

FUEL PUMP RELAY

IDLE AIR CONTROL (IAC)

OPERATOR INFORMATION LAMPS/BUZZERS

SERIAL DATA (ECM COMMUNICATION)

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

INTAKE AIR TEMPERATURE (IAT) (5.0/5.7L only)

KNOCK SENSOR 1

KNOCK SENSOR 2 (6.0/8.1L only)

DIAGNOSTIC ENABLE

GENERAL WARNING 2 (OIL PRESSURE)

C O N

T

R O

L

M O D U

L E

V- REFERENCE (5 VOLT OUTPUT TO SENSORS)

MALFUNCTION INDICATOR LAMP (MIL)

DEPSPOWER (12 VOLT OUTPUT TO SENSORS)

Figure 2-5 - ECM Inputs and Outputs (Typical)

MEFI 4 - PCM

2-13-04

MS 11699

5.0/5.7/6.0L/8.1L ECM and Sensors 2 - 7

Engine Coolant Temperature (ECT) Sensor

The engine coolant temperature (ECT) sensor is a thermistor (a resistor which changes value based on temperature) mounted in the engine coolant stream. Low coolant temperature produces a high resistance (100,000 ohms at -40°C/-40°F) while high temperature causes low resistance (70 ohms at 130°C/266°F).

The ECM supplies a 5 volt signal to the ECT sensor through a resistor in the ECM and measures the voltage. The voltage will be high when the engine is cold, and low when the engine is hot. By measuring the v oltage, the ECM calculates the engine coolant temperature. Engine coolant temperature affects most systems the ECM controls.

A hard fault in the engine coolant sensor circuit should set DTC 14 or DTC 15; an intermittent fault may or may not set a DTC. The DTC “Diagnostic Aids” also contains a chart to check for sensor resistance values relative to temperature.

3

1

2

The ECM supplies a 5 volt reference voltage to the MAP sensor. As the manifold pressure changes, the electrical resistance of the MAP sensor also changes. By monitoring the sensor output voltage, the ECM knows the manifold pressure. A higher pressure, low vacuum (high voltage) requires more fuel. A lower pressure, high vacuum (low voltage) requires less fuel. The ECM uses the MAP sensor to control fuel delivery and ignition timing. A failure in the MAP sensor circuit should set a DTC 33 or DTC 34.

1HARNESS CONNECTOR 2LOCKING TAB 3SENSOR

Figure 2-6 - Engine Coolant Temperature (ECT) Sensor



8-24-94

RS 22189

Manifold Absolute Pressure (MAP) Sensor

The Manifold Absolute Pressure (MAP) sensor is a pressure transducer that measures the changes in the intake manifold pressure. The pressure changes as a result of engine load and speed change, and the MAP sensor converts this into a voltage output.

A closed throttle on engine coastdown would produce a relatively low MAP output voltage, while a wide open throttle would produce a high MAP output voltage. This high output voltage is produced because the pressure inside the manifold is almost the same as outside the manifold, so you measure almost 100% of outside air pressure. MAP is the opposite of what you would measure on a vacuum gauge. When manifold pressure is high, vacuum is low, causing a high MAP output voltage. The MAP sensor is also used to measure barometric pressure under certain conditions, which allows the ECM to automatically adjust for different altitudes.

Figure 2-7 - Manifold Absolute Pressure (MAP) Sensor/

Intake Air Temperature (IAT) Sensor

(Used On 5.0/5.7L Engines)

I 22312

Figure 2-8 - Manifold Absolute Pressure (MAP) Sensor

(Used On 6.0/8.1L Engines)

MEFI 4 - PCM

2 - 8 ECM and Sensors 5.0/5.7/6.0/8.1L

Throttle Position (TP) Sensor

The Throttle Position (TP) sensor is a potentiometer connected to the throttle shaft on the throttle body. By monitoring the voltage on the signal line, the ECM calculates throttle position. As the throttle valve angle is changed (accelerator pedal moved), the TP sensor signal also changes. At a closed throttle position, the output of the TP sensor is low. As the throttle valve opens, the output increases so that at Wide Open Throttle (WOT), the output voltage should be above 4 volts.

The ECM calculates fuel delivery based on throttle valve angle (driver demand). A broken or loose TP sensor may cause intermittent bursts of fuel from an injector and unstable idle because the ECM thinks the throttle is moving. A hard failure in the TP sensor circuit should set either a DTC 21 or DTC 22. Once a DTC is set, the ECM will use a calibratible default value for throttle position and some engine performance will return.

Intake Air Temperature (IAT) Sensor (5.0/5.7L)

The Intake Air Temperature (IAT) sensor is a thermistor which changes value based on the temperature of air entering the engine (Figure 2-12). Low temperature produces a high resistance (100,000 ohms at -40°C/-40°F) while high temperature causes low resistance (70 ohms at 130°C/266°F).

The ECM supplies a 5 volt signal to the sensor through a resistor in the ECM and measures the voltage. The voltage will be high when the incoming air is cold, and low when the incoming air is hot. By measuring the voltage, the ECM calculates the incoming air temperature. The IAT sensor signal is used to determine spark timing based on incoming air density.

The scan tool displays temperature of the air entering the engine, which should read close to ambient air temperature when engine is cold, and rise as engine compartment temperature increases. If the engine has not been run for several hours (overnight), the IAT sensor and ECT sensor temperatures should read close to each other. A failure in the IAT sensor circuit should set DTC 23 or DTC 25.

1

2

1 THROTTLE POSITION (TP) SENSOR  2 TP SENSOR ATTACHING SCREW

Figure 2-10 - Throttle Position (TP) Sensor (Typical)

C B

A

2

CONTROL MODULE

1

RS 22191

Figure 2-12 - Manifold Absolute Pressure (MAP) Sensor/

Intake Air Temperature (IAT) Sensor

(Used On 5.0/5.7L Engines)

Ignition Control (IC) Reference

The Ignition Control (IC) reference (RPM signal) is supplied to the ECM by way of the crankshaft position sensor. This pulse counter type input creates the timing signal for the pulsing of the fuel injectors, as well as the IC functions. This signal is used for a number of control and testing functions within the ECM.

1 THROTTLE POSITION (TP) SENSOR  2 THROTTLE VALVE

Figure 2-11 - Throttle Position (TP) Sensor (Typical)

MEFI 4 - PCM

RS 22192

5.0/5.7/6.0L/8.1L ECM and Sensors 2 - 9

Knock Sensor (KS) System Description

Purpose:

To control spar k knock (detonation), a knock sensor (KS) system is used. This system is designed to retard spark timing when excessive spark knock is detected in the engine. The KS system allows the engine to use maximum spark advance for optimal driveability and fuel economy under all operating conditions.

Operation:

The ECM uses a knock sensor(s) to detect abnormal vibration in the engine (detonation/spark knock). Mounted on the engine block, the knock sensor(s) produces an AC voltage signal at all engine speeds and loads. The ECM then adjusts the spar k timing based on the amplitude and frequency of the KS signal. The ECM uses the KS signal to calculate an average voltage. Then, the ECM assigns a voltage range above and below the average voltage value. The ECM checks the KS and related wiring by comparing the actual knock signal to the assigned voltage range. A normal KS signal should vary outside the assigned voltage range as shown in the NORMAL KS ﬁ gure. If the ECM detects a KS signal within the assigned voltage range as shown in the ABNORMAL KS ﬁ gure, the applicable DTC will set.

Abnormal Knock Sensor Signal

Legend

1. Upper fail region

2. Knock sensor calculated average

3. Knock sensor signal

4. Lower fail region

245257

Normal Knock Sensor Signal

245253

Discrete Switch Inputs

Several discrete switch inputs are utilized by the MEFI system to identify abnormal conditions that may affect engine operation. Pull-up and pull-down type switches are currently used in conjunction with the ECM to detect critical conditions to engine operation.

If a switch changes states from its normal at rest position, that is, normally closed to open, or normally open to closed, the ECM senses a change in voltage and responds by entering Power reduction mode.

This engine protection feature allows the operator normal engine operations up to 2500 RPM, but disables half the fuel injectors until the engine drops below 1200 RPM. Then normal engine operation is restored until the RPM limit is exceeded. This feature allows the operator a safe maneuvering speed while removing the possibility of high RPM engine operation until the problem is corrected.

Switches that may be used with the MEFI system to detect critical engine operation parameters are:

• Oil Pressure

MEFI 4 - PCM

2 - 10 ECM and Sensors 5.0/5.7/6.0/8.1L

Diagnosis

Engine Control Module (ECM)

To read and clear diagnostic trouble codes, use a scan tool or Diagnostic Trouble Code (DTC) tool.

Important: Use of a scan tool is recommended to clear diagnostic trouble codes from the ECM memory . Diagnostic trouble codes can also be cleared by using the DTC tool.

Since the ECM can have a failure which may affect more than one circuit, following the diagnostic procedures will determine which circuit has a problem and where it is.

If a diagnostic procedure indicates that the ECM connections or ECM is the cause of a problem and the ECM is replaced, but does not correct the problem, one of the following may be the reason:

• Check for good ECM power and grounds.

• There is a problem with the ECM terminal connections.

The diagnostic table will say ECM connections or ECM. The terminals may have to be removed from the connector in order to check them properly.

• EEPROM program is not correct for the application.

Incorrect components may cause a malfunction and may or may not set a DTC.

• The problem is intermittent. This means that the

problem is not present at the time the system is being checked. In this case, refer to the Symptoms portion of the manual and make a careful physical inspection of all portions of the system involved.

• Shorted relay coil or harness. Relays are turned

“ON” and “OFF” by the ECM using internal electronic switches called drivers. A shorted relay coil or harness may not damage the ECM but will cause the relay to be inoperative.

On-Board Service

Engine Control Module (ECM) Replacement

Notice: When replacing the ECM, the ignition must be “OFF” and disconnect the battery before disconnecting or reconnecting the ECM “J1” and “J2” connectors to prevent internal damage to the ECM.

Notice: T o prev ent possible electrostatic discharge damage to the ECM, do not touch the connector pins. The ECM is an electrical component. Do Not soak in any liquid cleaner or solvent, as damage may result.

Remove or Disconnect

1. Negative battery cable.

2. “J1” and “J2” connectors from ECM.

3. The ECM mounting screws.

4. ECM from mounting bracket.

Important

• Make sure the new ECM has the same part number

and service number as the old ECM, to insure proper engine performance.

Install or Connect

1. New ECM to mounting bracket.

2. The ECM mounting screws. Torque to 10-14 N•m (88-124 lb in).

3. “J1” and “J2” connectors to ECM.

4. Negative battery cable.

MEFI 4 - PCM

J2J1

MEFI3004

Figure 2-13 - Engine Control Module (ECM)

5.0/5.7/6.0L/8.1L ECM and Sensors 2 - 11 System Relay Replacement

Removal Procedure

1. Tur n the ignition OFF.

2. Remove the retainer.

3. Disconnect the system relay electrical connector.

4. Remove the system relay. Important: The system relay is an electrical component.

Do Not soak in any liquid or solvent as damage may result.

Installation Procedure

1. Install the system relay.

2. Reconnect the system electrical connector.

3. Install the retainer clip.

meﬁ 4337

Fuel Pump Relay Replacement

Removal Procedure

1. Turn the ignition OFF.

2. Remove the retainer.

3. Disconnect the fuel pump relay electrical connector.

4. Remove the fuel pump relay. Important: The fuel pump relay is an electrical

component. Do Not soak in any liquid or solvent as damage may result.

Installation Procedure

1. Install the fuel pump relay.

2. Reconnect the fuel pump relay electrical connector.

3. Install the retainer clip.

meﬁ 4337

Starter Relay Replacement

Removal Procedure

1. Turn the ignition OFF.

2. Remove the retainer.

3. Disconnect the star ter relay electrical connector.

4. Remove the starter relay. Important: The starter relay is an electrical component.

Do Not soak in any liquid or solvent as damage may result.

Installation Procedure

1. Install the starter relay.

2. Reconnect the star ter relay electrical connector.

3. Install the retainer clip.

meﬁ 4337

MEFI 4 - PCM

2 - 12 ECM and Sensors 5.0/5.7/6.0/8.1L

Engine Coolant Temperature (ECT) Sensor Replacement

Notice: Care must be taken when handling the ECT

sensor. Damage to the sensor will affect proper operation of the MEFI system.

Remove or Disconnect

1. Turn OFF the ignition.

2. Drain the cooling system below the level of the ECT sensor (if necessary).

3. Disconnect the ECT electrical connector.

4. Remove the ECT sensor.

meﬁ 4333

Installation Procedure

Important: Coat ECT sensor threads with Teﬂ on tape

sealant prior to installation.

1. Install the ECT sensor.

Tighten Tighten the ECT sensor to 20 N•m (15 lb ft).

2. Reconnect the ECT electrical connector.

3. Reﬁ ll the cooling system (if necessary).

MEFI 4 - PCM

meﬁ 4333

5.0/5.7/6.0L/8.1L ECM and Sensors 2 - 13

Manifold Absolute Pressure (MAP) / Intake Air Temperature (IAT) Sensor Replacement (5.0/5.7L)

Removal Procedure

1. Remove the MAP sensor retaining stud.

2. Remove the MAP sensor from the intake manifold.

3. Inspect the MAP sensor seal for wear or damage and replace as necessary.

map rr

Installation Procedure

Important: Lightly coat the MAP sensor seal with rubber

lubricant before installing the sensor. The lubricant should be applied with a sponge or brush. To prevent blockage, avoid dipping the sensor port directly into the lubricant.

1. Install the MAP sensor.

2. Install the MAP sensor retaining stud.

Tighten Tighten the MAP sensor retaining stud to 12 N•m

(106 lb in).

3. Connect the manifold absolute pressure (MAP) sensor electrical connector.

map rr

MEFI 4 - PCM

2 - 14 ECM and Sensors 5.0/5.7/6.0/8.1L

Manifold Absolute Pressure (MAP) Sensor Replacement (6.0/8.1L)

1

684798

Removal Procedure

1. Disconnect the manifold absolute pressure (MAP) sensor electrical connector (1).

2. Remove the MAP sensor retaining bolt and washer (1).

3. Remove the MAP sensor (3) from the intake manifold (2).

4. Inspect the MAP sensor seal for wear or damage and replace as necessary.

MEFI 4 - PCM

684801

Installation Procedure

Important: Lightly coat the MAP sensor seal with rubber

lubricant before installing the sensor. The lubricant should be applied with a sponge or brush. To prevent blockage, avoid dipping the sensor port directly into the lubricant.

1. Install the MAP sensor (3).

2. Install the MAP sensor retaining bolt and washer (1).

Tighten Tighten the MAP sensor retaining bolt to 12 N•m

(106 lb in).

684801

5.0/5.7/6.0L/8.1L ECM and Sensors 2 - 15

3. Connect the MAP sensor electrical connector (1).

1

684798

MEFI 4 - PCM

2 - 16 ECM and Sensors 5.0/5.7/6.0/8.1L

Throttle Position (TP) Sensor

Remove or Disconnect

1. Flame arrestor.

2. TP sensor electrical connector.

3. TP sensor attaching screws (1).

4. TP sensor (2).

1

Important

• The TP sensor is an electrical component. Do Not

soak in any liquid cleaner or solvent, as damage may result.

• If replacing TP sensor, install new screws that are

2

PS19190

1

supplied with the TP sensor service package.

Install or Connect

1. TP sensor over throttle shaft.

2. With throttle valve in the normal closed position (idle), install TP sensor on throttle body assembly, making sure TP sensor pickup lever lines up with the tang on the throttle actuator lever.

3. TP sensor attaching screws. Torque to 2 N•m (18 lb in).

4. TP sensor electrical connector.

5. Flame arrestor.

2

PS19190

MEFI 4 - PCM

5.0/5.7/6.0L/8.1L ECM and Sensors 2 - 17

Idle Air Control (IAC) Valve

Remove or Disconnect

1. Flame arrestor.

2. IAC electrical connector.

1

3. IAC valve attaching screws (1).

4. IAC valve (2).

2

Notice: On IAC valves that have been in service, Do Not push or pull on the IAC valve pintle. The force required to move the pintle may damage the threads on the worm drive. Also, Do Not soak IAC valve in any liquid cleaner or solvent, as damage may result.

Clean and Inspect

• Clean IAC valve O-ring sealing surface, pintle valve

seat and air passage.

– Use carburetor cleaner to remove carbon deposits.

Do Not use a cleaner that contains methyl ethyl ketone, an extremely strong solvent, and not necessary for this type of deposit.

– Shiny spots on the pintle or seat are normal,

and do not indicate misalignment or a bent pintle shaft.

Important

• If installing a new IAC valve, be sure to replace with

an identical part number. IAC valve pintle shape and diameter are designed for the speciﬁ c application.

Measure (If installing a new IAC valve)

• Distance between tip of IAC valve pintle and mounting

surface.

– If greater than 28 mm, use finger pressure to

slowly retract the pintle. The force required to retract the pintle of a new valve will not cause damage to the valve.

➤

A

➤

B

➤

1 O-RING - IAC VALVE  2 IAC VALVE ATTACHING SCREW  A DISTANCE OF PINTLE EXTENSION  B DIAMETER OF PINTLE

1

M4085

2

8-24-94

RS 22181

Install or Connect

1. New O-ring on IAC valve and lubricate. Notice: New IAC valves have been preset at the factory

and should not require any adjustment.

2. IAC valve to throttle body using attaching screws. Torque to 3.2 N•m (28 lb in).

3. IAC valve electrical connector.

4. Reset IAC valve pintle position:

• Turn ignition “OFF” for 10 seconds.

• Start and run engine for 5 seconds.

• Ignition “OFF” for 10 seconds.

• Restart engine and check for proper idle.

1

2

M4085

MEFI 4 - PCM

2 - 18 ECM and Sensors 5.0/5.7/6.0/8.1L

Knock Sensor (KS) (5.0/5.7L)

Remove or Disconnect

2

1. Negative battery cable.

2. Knock sensor electrical connector.

3. Knock sensor from engine block.

FRT

1

1 KNOCK SENSOR 2 ENGINE BLOCK

RS 22182

8-24-94

RS 22183

Install or Connect Important

• If installing a new knock sensor, be sure to replace

with an identical part number.

• When installing knock sensor, be sure to install in the

same location removed from.

• If installing knock sensor in water jacket, use Teﬂ on

sealer.

1. Knock sensor into engine block. Be sure threads are clean. Torque to 15-22 N•m (11-16 lb ft).

2. Knock sensor electrical connector.

3. Negative battery cable.

MEFI 4 - PCM

Knock Sensors (KS) (6.0L)

Remove or Disconnect

1. Remove the intake manif old. Ref er to Intake Manif old

Replacement in Engine Mechanical - 6.0L.

2. Gently pry up the rubber covers.

3. Disconnect the knock sensor electrical connectors.

5.0/5.7/6.0L/8.1L ECM and Sensors 2 - 19

4. Remove the knock sensors.

Install or Connect Important

• If installing a new knock sensor, be sure to replace

with an identical part number.

• When installing knock sensor, be sure to install in the

same location removed from.

1. Knock sensors into engine block. Be sure threads are clean. Torque to 20 N•m (15 lb ft).

2. Connect the knock sensor electrical connectors.

3. Push down on the rubber covers.

4. Install the intake manifold. Refer to Intake Manifold Replacement in Engine Mechanical - 6.0L.

MEFI 4 - PCM

2 - 20 ECM and Sensors 5.0/5.7/6.0/8.1L

Torque Speciﬁ cations

Fastener Tightening Speciﬁ cations (5.0/5.7L)

Application N•m Lb Ft Lb In

ECM Mounting Screws 10-14 88-124 ECT Sensor 12 108 MAP/IAT Sensor Attaching Stud 5-7 44-62 TP Sensor Attaching Screws 2 18 IAC Valve Attaching Screws 3.2 28 Knock Sensor 15-22 11-16

Fastener Tightening Speciﬁ cations (6.0/8.1L)

Application N•m Lb Ft Lb In

ECM Mounting Screws 10-14 88-124 ECT Sensor 12 108 MAP Sensor Attaching Screw 5-7 44-62 TP Sensor Attaching Screws 2 18 IAC Valve Attaching Screws 3.2 28 Knock Sensors 20 15

MEFI 4 - PCM

5.0/5.7L Fuel Metering System 3A - 1

Marine Electronic Fuel Injection (MEFI) Section 3A Fuel Metering System - 5.0/5.7L

This section describes how the fuel metering system operates, and provides a description of components used on the Marine Electronic Fuel Injection equipped engines. The fuel metering system information described in this section is limited to the 5.0/5.7L. All other systems will be detailed in a separate section.

Contents

General Description ..........................................Page 2

Purpose......................................................... Page 2

Modes of Operation ......................................Page 2

Starting Mode......................................... Page 2

Clear Flood Mode...................................Page 2

Run Mode...............................................Page 2

Acceleration Mode..................................Page 2

Fuel Cutoff Mode....................................Page 2

Power Reduction Mode.......................... Page 2

Fuel Metering System Components .............Page 2

Quick-Connect Fittings.................................. Page 2

Fuel Supply Components (FCC System) .... Page 3

Fuel Pump Electrical Circuit ......................... Page 4

Fuel Rail Assembly....................................... Page 4

Fuel Injectors..........................................Page 4

Pressure Regulator Assembly................Page 5

Throttle Body Assembly................................Page 5

Idle Air Control (IAC) Valve.....................Page 6

Diagnosis ...........................................................Page 6

On-Board Service ................................................Page 6

Fuel Control On-Board Service ...................... Page 7

Fuel Pressure Relief Procedure......................Page 7

Flame Arrestor................................................ Page 7

Throttle Body Assembly..................................Page 8

Quick Connect Fitting(s) Service

(Metal Collar) ..................................................Page 9

Fuel Rail Assembly....................................... Page 11

Fuel Injectors ................................................Page 13

Fuel Pressure Regulator Assembly.............. Page 14

Fuel Control Cell (FCC)................................ Page 15

Low-Pressure Fuel Pump .............................Page 18

Fuel Pump Relay ..........................................Page 18

Torque Speciﬁ cations ....................................... P age 19

MEFI 4 - PCM

3A - 2 Fuel Metering System 5.0/5.7L

General Description

Purpose

The function of the fuel metering system is to deliver the correct amount of fuel to the engine under all operating conditions. Fuel is delivered to the engine by individual fuel injectors mounted in the intake manifold near each cylinder.

Modes Of Operation

The ECM looks at inputs from several sensors to determine how much fuel to give the engine. The fuel is delivered under one of several conditions, called “modes.” All the “modes” are controlled by the ECM and are described below.

Starting Mode

When the ignition switch is turned to the crank position, the ECM turns the fuel pump relay “ON,” and the fuel pump builds up pressure. The ECM then checks the ECT, MAP and TP sensors, and determines the proper air/fuel ratio for starting. The ECM controls the amount of fuel delivered in the starting mode by changing how long the injectors are turned “ON” and “OFF.” This is done by “pulsing” the injectors for very short times.

Clear Flood Mode

If the engine ﬂ oods, it can be cleared by opening the throttle to 100% (wide open throttle) during cranking. The ECM then shuts down the fuel injectors so no fuel is delivered. The ECM holds this injector rate as long as the throttle stays at 100%, and the engine speed is below 300 RPM. If the throttle position becomes less than 100%, the ECM returns to the starting mode.

Run Mode

When the engine is ﬁ rst started and RPM is above 300 RPM, the system operates in the run mode. The ECM will calculate the desired air/fuel ratio based on these ECM inputs: RPM, ECT and MAP. Higher engine loads (MAP input) and colder engine temperatures (ECT input) require more fuel, or a richer air/fuel ratio.

Acceleration Mode

The ECM looks at rapid changes in TP sensor and MAP, and provides extra fuel by increasing the injector pulse width.

Fuel Cutoff Mode

No fuel is delivered by the injector when the ignition is “OFF,” to prevent dieseling. Also, injector pulses are not delivered if the ECM does not receive distributor reference pulses, which means the engine is not running. The fuel cutoff mode is also enabled at high engine RPM, as an overspeed protection for the engine. When fuel cutoff is in effect due to high RPM, injector pulses will resume after engine RPM drops below the maximum OEM RPM speciﬁ cation (Rev Limit).

Power Reduction Mode

Power reduction mode is a function of the ECM that reduces

engine power under certain conditions. Power reduction will disable one fuel injector driver when the engine speed goes above 2500 rpm, and enable the fuel injector driver when the engine speed drops below 1200 rpm. Power reduction may be active for the following conditions:

• Engine coolant temperature too high

• Low oil pressure

• Transmission temperature too high (if applicable)

Fuel Metering System Components

The fuel metering system (Figure 3-1) is made up of the following parts:

Fuel supply components (fuel tank, pump, lines, ﬁ lter).

•

Fuel pump electrical circuit.

•

Fuel rail assembly, including fuel injectors and pressure

•

regulator assembly.

Throttle body assembly, including an IAC valve and

•

TP sensor.

Quick-Connect Fittings

Quick-Connect ﬁ ttings provide a simpliﬁ ed means of installing and connecting fuel system components. The ﬁ ttings consists of a unique female connector and a compatible male pipe end. O-rings, located inside the female connector, provide the fuel seal. Integral locking tabs inside the female connector hold the ﬁ ttings together.

Fuel Supply Components (FCC System)

The Fuel Control Cell (FCC) incorporates two (2) fuel pumps to provide uninterrupted ﬂ ow of fuel to your marine engine.

Fuel is fed into the FCC by a low-pressure, high volume electric fuel pump. This pump ﬂ ows fuel at a volume which exceeds the fuel flow rate required of the high-pressure pump by engine demands.

The high pressure pump, mounted inside the FCC bowl, provides the necessary fuel pressure and volume to maintain proper engine performance, and always has an ample supply of fuel to meet the idle, cruise and acceleration fuel requirements fo the engine.

The fuel pressure regulator, located on the fuel rail, controls fuel pressure and maintains a constant pressure across the fuel delivery system. Fuel not used by the engine, excess fuel, is returned to the FCC canister.

The fuel delivered to the engine by the FCC is ﬁ ltered by a ﬁ lter and water separator element, which surrounds the high pressure pump inside the FCC bowl.

The fuel enters the FCC bowl from two (2) components, the low-pressure pump (initial input) and the fuel pressure regulator (unused recirculating). Fuel exits the FCC bowl at two (2) locations, the high-pressure output to the fuel rail and all excess fuel in the FCC bowl is routed back to the fuel tank via a return line.

MEFI 4 - PCM

5.0/5.7L Fuel Metering System 3A - 3

PRESSURE

REGULATOR

FUEL RAIL ASSEMBLY

ENGINE

Fuel Control Cell Fuel System

LOW-

PRESSURE

FUEL

CONTROL

CELL

Figure 3-1 - Fuel Metering System (Typical)

FUEL

PUMP

FUEL

FILTER

FUEL TANK

Figure 3-2 - Typical Fuel Control Cell (FCC)

Figure 3-3 - Low Pressure Fuel Pump

MEFI 4 - PCM

3A - 4 Fuel Metering System 5.0/5.7L

Fuel Pump Electrical Circuit

When the ignition switch is turned “ON,” the ECM turns the fuel pump relay “ON” for two seconds causing the fuel pump(s) to pressurize the MEFI fuel system.

When the ignition switch is turned to the crank position, the ECM turns the fuel pump relay “ON” causing the fuel pump to run.

If the ECM does not receive ignition reference pulses (engine cranking or running), it shuts “OFF” the fuel pump relay, causing the fuel pump to stop.

An inoperative fuel pump relay will result in an “Engine Cranks But Will Not Run” condition.

Fuel Rail Assembly

The fuel rail (Figure 3-3) is mounted to the engine intake manifold, and performs several functions. It positions the injectors in the intake manifold, distributes fuel evenly to the injectors, and integrates the fuel pressure regulator into the fuel metering system.

Fuel Injectors

The fuel injector assembly is a solenoid-operated device, controlled by the ECM, that meters pressurized fuel to a single engine cylinder (Figure 3-4). The ECM energizes the injector solenoid, which opens a ball valve, allowing fuel to ﬂ ow past the ball valve, and through a recessed ﬂ ow director plate. The director plate has six machined holes that control the fuel ﬂ ow, generating a conical spray pattern of ﬁ nely atomized fuel at the injector tip. Fuel is directed at the intake valve, causing it to become further atomized and vaporized before entering the combustion chamber.

An injector that is stuck partly open would cause loss of pressure after engine shut down. Consequently, long cranking times would be noticed. Dieseling could also occur, because some fuel could be deliv ered to the engine after the ignition is turned “OFF.” A fuel injector that does not open, may cause a “no-start” or a misﬁ re.

11

Figure 3-3 - Fuel Rail Assembly

10

9

8

7

6

1 SOLENOID ASSEMBLY  2 SPACER AND GUIDE ASSEMBLY  3 CORE SEAT  4 BALL VALVE  5 SPRAY TIP  6 DIRECTOR PLATE

1

2

3

4

5

7 SPRAY HOUSING  8 CORE SPRING  9 SOLENOID HOUSING  10 SOLENOID  11 FUEL INLET FILTER 

4-11-96

9P 0413-SY

MEFI 4 - PCM

Figure 3-4 - Fuel Injector Assembly (Typical)

5.0/5.7L Fuel Metering System 3A - 5

Pressure Regulator Assembly

The pressure regulator is a diaphragm-operated relief valve with fuel pump pressure on one side, and regulator spring pressure and intake manifold vacuum on the other side (Figure 3-5). The regulator’s function is to maintain a constant pressure differential across the injectors at all times. The pressure regulator compensates for engine load by increasing fuel pressure as engine vacuum drops.

With the ignition “ON,” engine “OFF” (zero vacuum), fuel pressure at the pressure test connection should be 284-325 kPa (41-47 psi). If the pressure is too low, poor performance or a “no-start” may result. If pressure is too high, excessive odor may result.

Throttle Body Assembly

The throttle body assembly is attached to the intake manifold air plenum, and is used to control air ﬂ ow into the engine, thereby controlling engine output (Figure 3-6). The throttle plates within the throttle body are opened by the driver through the throttle controls. During engine idle, the throttle plates are closed, and air ﬂ ow control is handled by the Idle Air Control (IAC) valve, described below.

The throttle body also provides the location for mounting the TP sensor and for sensing changes in engine vacuum due to throttle plates position.

1

8

7

6

5

1 COVER  2 VACUUM CHAMBER (VACUUM SOURCE TUBE NOT SHOWN)  3 O - RING SEAL  4 FUEL PRESSURE REGULATOR VALVE  5 BASE ASSEMBLY  6 FILTER SCREEN (IF EQUIPPED)  7 DIAPHRAGM  8 SPRING

2

3

4

4-11-96

NA 0493-SY

Figure 3-6 - Throttle Body Assembly

Figure 3-5 - Pressure Regulator Assembly (Typical)

MEFI 4 - PCM

3A - 6 Fuel Metering System 5.0/5.7L

Idle Air Control (IAC) Valve

The purpose of the IAC valve assembly (Figures 3-7 and 3-8) is to control engine idle speed, while preventing stalls due to changes in engine load.

The IAC valve, mounted to the throttle body, controls bypass air around the throttle plates (Figure 3-7). By moving a conical valve known as a pintle, IN, towards the seat (to decrease air ﬂ ow); or OUT, away from the seat (to increase air ﬂ ow), a controlled amount of air moves around the throttle plates. If RPM is too low, more air is bypassed around the throttle plates to increase it. If RPM is too high, less air is bypassed around the throttle plates to decrease it.

The ECM moves the IAC valve in small steps. These can be monitored by scan tool test equipment, which plugs into the Data Link Connector (DLC).

During idle, the proper position of the IAC valve is calculated by the ECM, based on battery voltage, coolant temperature and engine RPM. If the RPM drops below speciﬁ cation and the throttle plates are closed, the ECM senses a near stall condition and calculates a new valve position to prevent stalling.

Engine idle speed is a function of total air ﬂ ow into

•

the engine based on IAC valve pintle position plus throttle plates opening.

1

2

“Controlled” idle speed is programmed into the ECM,

•

which determines the correct IAC valve pintle position to maintain the desired idle speed for all engine operating conditions and loads.

The minimum air rate is set at the factory with a stop

•

screw . This setting allows enough air ﬂ ow by the throttle plates to cause the IAC valve pintle to be positioned at a calibrated number of steps (counts) from the seat, during “controlled” idle operation. This minimum air rate setting should not be altered by turning the stop screw or bending the linkage. Improper idle control will result.

➤

A

➤

B

➤

1 O-RING - IAC VALVE  2 IAC VALVE ATTACHING SCREW  A DISTANCE OF PINTLE EXTENSION  B DIAMETER OF PINTLE

Figure 3-8 - Flange Mounted Type IAC Valve

1

2

8-24-94

RS 22181

A

4

B

1 IDLE AIR CONTROL (IAC) VALVE  2 THROTTLE BODY ASSEMBLY  3 THROTTLE VALVE  4 IAC VALVE PINTLE  A ELECTRICAL INPUT SIGNAL  B AIR INLET

Figure 3-7 - IAC Valve Air Flow Diagram

3

8-25-94

RS 22193

Diagnosis

If the Engine Cranks But Will Not Run or immediately stalls, Table A-3 of the Diagnosis section must be used to determine if the failure is in the ignition system or the fuel system.

On-Board Service

Caution: To reduce the risk of ﬁ re and personal injury, relieve

fuel system pressure before servicing fuel system components.

After relieving fuel pressure, a small amount of fuel may be released when servicing fuel lines or connections. To reduce the chance of personal injury, cover fuel line ﬁ ttings with a shop towel before disconnecting to catch any fuel that may leak out. Place the towel in an approved container when disconnection is completed.

MEFI 4 - PCM

5.0/5.7L Fuel Metering System 3A - 7

Fuel Control On-Board Service

The following is general inf ormation required when working on the fuel system:

Always keep a dry chemical fire extinguisher near

•

the work area.

Fuel pipe fittings require new O-rings when

•

assembling.

Do not replace fuel pipe with fuel hose.

•

Always bleed off fuel pressure before servicing any

•

fuel system components.

Do not do any repairs on the fuel system until you

•

have read the instructions and checked the ﬁ gures relating the repair.

Observe all notices and cautions.

•

Fuel Pressure Relief Procedure

Tool Required: J 34730-1, Fuel Pressure Gauge

Important

Refer to manufacturer’s warnings and cautions before

•

proceeding.

1. Disconnect negative battery cable to avoid possible fuel discharge if an accidental attempt is made to start the engine.

2. Loosen fuel filler cap to relieve any tank vapor pressure.

3. Connect fuel pressure gauge J 34730-1 to fuel pressure connector assembly. Wrap a shop towel around ﬁ tting while connecting the gauge to avoid any spillage.

4. Install bleed hose into an approved container and open valve to bleed system pressure. Fuel connections are now safe for servicing.

5. Drain any fuel remaining in the gauge into an approved container.

Flame Arrestor

Remove or Disconnect

1. Flame arrestor retaining clamp.

2. Flame arrestor.

Inspect

Flame arrestor element for dust, dirt or water. Replace

•

if required.

Install or Connect

1. Flame arrestor to throttle body.

2. Flame arrestor retaining clamp to ﬂ ame arrestor.

Figure 3-9 - Fuel Rail and Throttle Body Assemblies

MEFI 4 - PCM

3A - 8 Fuel Metering System 5.0/5.7L

Throttle Body Assembly

The throttle body assembly repair procedures cover component replacement with the unit on the vessel. However, throttle body replacement requires that the complete unit be removed from the engine.

Clean Important

Do not soak the throttle body in cold immersion type

•

cleaner. The throttle valves have a factory applied sealing compound (DAG material is applied to outside edge of each valve and throttle bore) to prevent air bypass at closed throttle. Strong solvents or brushing will remove the material. To clean the throttle body following disassembly, use a spray type cleaner such as GM X66-A or GM 1052626. Use a shop towel to remove heavy deposits.

Notice: The TP sensor and the IAC valve are electrical components and should NOT come in contact with solvent or cleaner as they may be damaged.

Remove or Disconnect

1. Negative battery cable.

2. Flame arrestor.

3. Electr ical connectors from TP sensor and IAC valve.

4. Throttle cable.

5. Throttle body attaching bolts.

6. Throttle body assembly and ﬂ ange gasket.

• Discard gasket.

Clean

Notice: Use care in cleaning old gasket material from machined aluminum surfaces as sharp tools may damage sealing surfaces.

Gasket sealing surfaces.

•

Install or Connect

1. Throttle body assembly with new ﬂ ange gasket.

2. Throttle body attaching bolts. Torque to 15 N•m (11 lb.ft.).

3. Throttle cable to throttle body.

4. Electr ical connectors to TP sensor and IAC valve.

5. Flame arrestor.

6. Negative battery cable.

Inspect

With the engine “OFF,” check to see that the throttle

•

lever is free.

– Move the throttle lever to wide open throttle and

release.

Reset IAC valve pintle position:

Move throttle lever slightly.

•

Start and run engine for 5 seconds.

•

Turn ignition “OFF” for 10 seconds.

•

Restart engine and check for proper idle operation.

•

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Turn the ignition switch back to the “ON” position and check for fuel leaks.

MEFI 4 - PCM

5.0/5.7L Fuel Metering System 3A - 9

Quick Connect Fitting(s) Service

Tools Required

J 37088-A Tool Set, Fuel Line Quick-Connect Separator J 44581 Fuel Line Quick Connect Separator

Removal Procedure

1. Relieve the fuel system pressure before servicing any fuel system connection. Refer to Fuel Pressure

Relief Procedure.

2. Remove the retainer from the quick-connect ﬁ tting.

Caution: Wear safety glasses in order to avoid eye damage.

3. Blow dirt out of the ﬁ ttig using compressed air.

12776

4. Choose the correct tool from the tool set for the size of the ﬁ tting. Insert the tool into the female connector, then push inward in order to release the locking tabs.

5. Pull the connection apart.

6. Use a clean shop towel in order to wipe off the male pipe end.

7. Inspect both ends of the ﬁ tting for dirt and burrs. Clean or replace the components as required.

12780

12782

MEFI 4 - PCM

3A - 10 Fuel Metering System 5.0/5.7L

Installation Procedure

1. Apply a few drops of clean engine oil to the male pipe end.

12784

2. Push both sides of the ﬁ tting together in order to snap the retaining tabs into place.

MEFI 4 - PCM

12786

3. Once installed, pull on both sides of the ﬁ tting in order to make sure the connection is secure.

4. Install the retainer to the quick-connect ﬁ tting.

12787

5.0/5.7L Fuel Metering System 3A - 11

Fuel Rail Assembly

The fuel rails should be removed as an assembly with the injectors attached. Names of component parts will be found on the numbered list that accompanies the disassembled view.

Notice:

Use care in removing the fuel rail assembly to prevent

•

damage to the injector electrical connector terminals and the injector spray tips.

When removed, support the rail to avoid damaging

•

its components.

Prevent dirt and other contaminants from entering

•

open lines and passages. Fittings should be capped and holes plugged during servicing.

Clean

Before removal, the fuel rail assemb ly may be cleaned

•

with a spray type engine cleaner, GM X-30A or equivalent, following package instructions. Do Not soak fuel rails in liquid cleaning solvent.

Caution: Safety glasses must be worn when using compressed air as flying dirt particles may cause eye injury.

Where injectors ﬁ t into intake manifold, use compressed

•

air to blow out dirt from around injectors before removing.

Remove or Disconnect

Caution: To reduce the risk of ﬁ re and personal injury, relieve the fuel system pressure before servicing the fuel system components.

1. Negative battery cable.

2. Relieve fuel pressure.

• Refer to the “Fuel Pressure Relief Procedure.” Fuel pressure connector assembly is located on

•

the fuel rail.

3. Fuel inlet line, follow procedure for Quick Connect

Fittings outlined in this section.

4. Fuel outlet line, follow procedure for Quick Connect

Fittings outlined in this section.

5. Vacuum line to fuel pressure regulator.

6. Electrical connectors from injectors.

7. Move wire harness out of way.

8. Four attaching screws for fuel rail.

9. Fuel rails as an assembly with injectors.

10. Injectors from rails, follow procedure for injector

removal outlined in this section.

Clean and Inspect

Notice: If it is necessary to remove rust or burrs from the fuel rail pipes, use emery cloth in a radial motion with the tube end to prevent damage to the O-ring sealing surface.

Use a clean shop towel to wipe off male pipe ends.

•

Inspect all connectors for dirt and burrs. Clean or

•

replace components/assemblies as required.

Disassemble

Injector O-ring seal from spray tip end of each injector.

•

Discard O-ring seals.

Assemble

Lubr icate new injector O-ring seals with clean engine

•

oil and install on spray tip end of each injector.

Install or Connect

1. Lubricate injector O-ring seals and install injectors following injector installation procedure outlined in this section.

2. Fuel rails as an assembly with injectors onto intake manifold.

If injectors are lined up properly they will slide into

•

place.

Push gently and evenly on rail to set injectors all

•

the way into their bores

3. Fuel rail attaching screws. Torque to 10 N•m (88 lb.in.).

4. Injector electrical connectors and secure harness in place.

5. Vacuum line to fuel pressure regulator.

6. Fuel inlet line, follow procedure for Quick Connect Fittings outlined in this section.

7. Fuel outlet line, follow procedure for Quick Connect Fittings outlined in this section.

8. Negative battery cable.

9. Prime fuel system by cycling key “ON” and “OFF” a few times with engine “OFF.”

MEFI 4 - PCM

3A - 12 Fuel Metering System 5.0/5.7L

Fuel Rail Removal and Installation

2

1

9

8

7

6

5

3

Legend

(1) Fuel Rail Attaching Stud (2) Fuel Pressure Connection Cap (3) Fuel Rail Assembly (4) Fuel Injector O-Ring (5) Fuel Injector Assembly

MEFI 4 - PCM

4

Fuel Rail Assembly

(6) Fuel Injector Retaining Clip (7) Fuel Pressure Regulator (8) Fuel Pressure Regulator Retaining Clip (9) Fuel Pressure Regulator Vacuum LIne

5.0/5.7L Fuel Metering System 3A - 13

Fuel Injectors

Notice: Use care in removing injectors to prevent damage to the injector electrical connector pins or the injector spray tips. The fuel injector is ser viced as a complete assembly only. Since it is an electrical component, Do Not immerse it in any cleaner.

Remove or Disconnect

1. Negative battery cable.

2. Relieve fuel pressure.

• Refer to the “Fuel Pressure Relief Procedure.”

3. Fuel rail assembly following the procedures outlined in this section.

Disassemble

1. Release injector clip by sliding off injector.

2. Fuel injector from rail.

3. Injector O-ring seals from both ends of the injector and discard.

4. Injector retainer clip from rail.

Clean and Inspect

Injector bores in fuel rail and intake manifold for nicks,

•

burrs or corrosion damage. If severe, replace. Clean lightly with emery cloth in a radial motion.

Injector O-ring seal grooves for nicks , burrs or corrosion.

•

Replace injector if damaged. Clean with spray cleaner and wipe groove clean with lint free cloth.

Do Not use abrasive materials or wire brush on

•

injectors. They are plated with an anti-corrosive material.

B

Fuel Injector and Retainer Clip

1

A

E

D

C

Important

When ordering individual replacement fuel injectors, be

•

sure to order the identical part number that is inscribed on the old injector.

Assemble

1. Lubricate new injector O-ring seals with clean engine oil and install on injector.

2. New retainer clip onto injector.

3. Fuel fuel injector assembly into fuel rail injector socket with electrical connector facing outward.

4. Rotate injector retainer clip to locking position.

Install or Connect

1. Fuel rail assembly following procedures outlined in this section.

2. Negative battery cable.

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Turn the ignition switch back to the “ON” position and check for fuel leaks.

1 FUEL INJECTOR ASSEMBLY  A PART NUMBER IDENTIFICATION  B BUILD DATE CODE  C MONTH 1-9 (JAN-SEPT) O,N,D (OCT,NOV,DEC)  D DAY  E YEAR

Injector Part Number Location

4-11-96

MP 1222-AS

MEFI 4 - PCM

3A - 14 Fuel Metering System 5.0/5.7L

Fuel Pressure Regulator Assembly

Important

The fuel pressure regulator is ser viced as a complete

•

assembly only.

Fuel pressure must be relieved before servicing the

•

fuel system.

Refer to “Fuel Pressure Relief Procedure.”

•

Remove or Disconnect

1. Negative battery cable.

2. Vacuum hose from regulator.

3. Fuel outlet line nut.

• Use back up wrench to hold pressure regulator to keep from turning and damage.

• Discard outlet line nut O-ring.

4. Pressure regulator attaching screw.

5. Pressure regulator from fuel rail.

6. Pressure regulator O-ring and discard.

Inspect

The fuel input port of the pressure regulator may

•

contain a ﬁ lter screen. Inspect the screen for dirt and debris. If dirty, use a pick to remove ﬁ lter screen and discard. Replace with new ﬁ lter screen supplied in service package.

Install or Connect

1. Lubricate new fuel pressure regulator O-ring with clean engine oil and install on regulator.

2. Push pressure regulator into rail.

3. Pressure regulator attaching screw. Finger tighten only.

4. Lubricate new outlet line O-ring and install on end of line.

5. Outlet line assembly with nut to pressure regulator. Finger tighten only.

6. Torque pressure regulator attaching screw to 9.5 N•m (84 lb.in.).

7. Torque outlet line nut to 17.5 N•m (13 lb.ft.).

• Use backup wrench to keep pressure regulator from turning and damage.

8. Vacuum line to pressure regulator.

9. Negative battery cable.

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Turn the ignition switch back to the “ON” position and check for fuel leaks.

MEFI 4 - PCM

Fuel Pressure Regulator

5.0/5.7L Fuel Metering System 3A - 15

Fuel Control Cell (FCC) Replacement - Screw On Bowl and Clamp On Bowl

Important

Fuel pressure must be relieved before servicing the

•

fuel pump.

Refer to “Fuel Pressure Relief Procedure.”

•

Remove or Disconnect

1. Negative battery cable.

2. Fuel pump electrical connector.

3. Inlet and outlet fuel line ﬁ ttings.

4. Fuel Control Cell (FCC) attaching bolts.

5. Fuel Control Cell (FCC).

Install or Connect

1. Fuel Control Cell (FCC).

2. Fuel Control Cell (FCC) attaching bolts.

3. Inlet and outlet fuel line ﬁ ttings.

4. Fuel pump electrical connector.

5. Negative battery cable.

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Turn the ignition switch back to the “ON” position and check for fuel leaks.

Fuel Control Cell (FCC) - Screw On Bowl

Fuel Control Cell (FCC) - Clamp On Bowl

MEFI 4 - PCM

3A - 16 Fuel Metering System 5.0/5.7L

Fuel Control Cell (FCC) - Screw On Bowl Drain Water (With Engine OFF)

1. Disconnect the two-wire electrical harness.

2. Hold the 3/4” jam nut located at the bottom of the FCC bowl with a wrench, remove the 3/16” allen plug and drain bowl contents into a suitable container.

Caution: Both fuel, which is explosive, and water will drain from the FCC bowl.

3. Apply pipe sealant suitable for use with gasoline to the threads fo the 3/16” allen plug.

4. Tighten the 3/16” allen plug while holding the 3/4” jam nut with a wrench.

5. Re-connect the two-wire electrical harness.

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Cycle the ignition several times to ﬁ ll the FCC bowl. Turn the ignition switch back to the “ON” position and check for fuel leaks.

FUEL

PRESSURE

REGULATOR

FUEL

PUMP

OR

"O"- RING

FUEL

FILTER

FUEL

PUMP

Fuel Control Cell (FCC) - Screw On Bowl Element Replacement (With Engine OFF)

1. Disconnect the two-wire electrical harness.

2. Hold the 3/4” jam nut located at the bottom of the FCC bowl with a wrench, remove the 3/16” allen plug and drain bowl contents into a suitable container.

Caution: Both fuel, which is explosive, and water will drain from the FCC bowl.

3. Using a strap type oil ﬁ lter wrench, remove the bowl by turning it counterclockwise as viewed from the bottom.

4. Slide bowl downward over the suspended ﬁ lter element. It may be necessary to pull the unit to one side or remove the fuel line from the feed pump to remove the bowl.

5. Remove the fuel ﬁ lter element from the suspended pump by gripping the fuel pump with one hand and pulling the ﬁ lter downward with the other hand.

6. Push on new ﬁ lter element over the electric pump.

7. Using a pick made of soft material, such as a toothpick, remove the old “O”-ring from inside the FCC bowl mounting head.

Caution: The mounting head “O”-ring groove may be damaged by using a sharp tool to remove this “O”-ring.

8. Lubricate the new “O”-ring with a light grease and install the new “O”-ring in the FCC head.

9. Grease taper and threads on the bowl and, by hand, thread the bowl into the FCC mounting head. Tighten the bowl ﬁ rmly back into the head with an oil ﬁ lter wrench.

10. Apply pipe sealant suitable with gasoline to the 3/16” allen plug.

11. Install and tighten the 3/16” allen plug while holding the 3/4” jam nut with a wrench.

12. Re-connect the two-wire electrical harness.

FUEL

BOWL

FUEL

DRAIN

MEFI 4 - PCM

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Cycle the ignition several times to ﬁ ll the FCC bowl. Turn the ignition switch back to the “ON” position and check for fuel leaks.

5.0/5.7L Fuel Metering System 3A - 17

Fuel Control Cell (FCC) - Clamp On Bowl Drain Water (With Engine OFF)

1. Disconnect the two-wire electrical harness.

2. Remove the 7/16” plug and drain the bowl contents into a suitable container.

Caution: Both fuel, which is explosive, and water will drain from the FCC bowl.

3. Apply pipe sealant, suitable for use with gasoline, to the threads fo the 7/16” plug.

4. Install and tighten the 7/16” plug securely.

5. Reconnect the two-wire electrical harness.

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Cycle the ignition several times to ﬁ ll the FCC bowl. Turn the ignition switch back to the “ON” position and check for fuel leaks.

6.0L 5.0/5.7L OR

O-RINGS

FUEL

PRESSURE

REGULATOR

Fuel Control Cell (FCC) - Clamp On Bowl Element Replacement (With Engine OFF)

1. Disconnect the two-wire electrical harness.

2. Remove the 7/16” plug and drain the bowl contents into a suitable container.

Caution: Both fuel, which is explosive, and water will drain from the FCC bowl.

3. Remove the canister retaining clamp.

4. Slide bowl downward over the suspended ﬁ lter element. It may be necessary to pull the unit to one side to remove the bowl.

5. Remove the fuel ﬁ lter element from the suspended pump by gripping the fuel pump with one hand and pulling the ﬁ lter downward with the other hand.

6. Push on new ﬁ lter element over the electric pump.

7. Using a pick made of soft material, such as a toothpick, remove the old “O”-rings from the FCC bowl mounting head.

Caution: The mounting head “O”-ring grooves may be damaged by using a sharp tool to remove these “O”-rings.

8. Lubricate the new “O”-rings with fuel resistant “O”-ring lubricant, and install the new “O”-rings on the FCC head.

9. Apply pipe sealant, suitable for use with gasoline, to the threads fo the 7/16” plug.

10. Install and tighten the 7/16” plug securely.

11. Install the bowl ﬁ rmly back onto the FCC head.

12. Install the canister retaining clamp and tighten securely.

13. Reconnect the two-wire electrical harness.

FUEL

PUMP

FUEL

FILTER

RETAINING

CLAMP

FUEL

BOWL

FUEL

DRAIN

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Cycle the ignition several times to ﬁ ll the FCC bowl. Turn the ignition switch back to the “ON” position and check for fuel leaks.

MEFI 4 - PCM

3A - 18 Fuel Metering System 5.0/5.7L

Low-Pressure Fuel Pump Replacement

Important

Fuel pressure must be relieved before servicing the

•

fuel pump.

Refer to “Fuel Pressure Relief Procedure.”

•

Remove or Disconnect

1. Negative battery cable.

2. Fuel pump electrical connector.

3. Inlet and outlet fuel line ﬁ ttings.

4. Fuel pump attaching bolts.

5. Fuel pump.

Install or Connect

1. Fuel pump.

2. Fuel pump attaching bolts.

3. Inlet and outlet fuel line ﬁ ttings.

4. Fuel pump electrical connector.

5. Negative battery cable.

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Turn the ignition switch back to the “ON” position and check for fuel leaks.

Fuel Pump Relay

Remove or Disconnect

1. Retainer, if installed.

2. Fuel pump relay electrical connector.

3. Fuel pump relay.

MEFI 4 - PCM

PS 16871

Important

The fuel pump relay is a electrical component. Do

•

Not soak in any liquid cleaner or solvent as damage may result.

Install or Connect

1. Fuel pump relay.

2. Fuel pump relay electrical connector.

3. Retainer clip.

5.0/5.7L Fuel Metering System 3A - 19

Torque Speciﬁ cations

Fastener Tightening Speciﬁ cations

Application N•m Lb Ft Lb In

Throttle Body Attaching Screws 15 11 IAC Valve Attaching Screws 3.2 28 Fuel Pressure Connector 13 115 Fuel Rail Attaching Screws 10 88

MEFI 4 - PCM

3A - 20 Fuel Metering System 5.0/5.7L

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intentionally

blank

MEFI 4 - PCM

6.0L Fuel Metering System 3B - 1

Marine Electronic Fuel Injection (MEFI) Section 3B Fuel Metering System - 6.0L

This section describes how the fuel metering system operates, and provides a description of components used on the Marine Electronic Fuel Injection equipped engines. The fuel metering system information described in this section is limited to the 6.0L. All other systems will be detailed in a separate section.

Contents

General Description .............................................Page 2

Purpose............................................................Page 2

Modes of Operation .........................................Page 2

Starting Mode............................................Page 2

Clear Flood Mode......................................Page 2

Run Mode..................................................Page 2

Acceleration Mode.....................................Page 2

Fuel Cutoff Mode.......................................Page 2

Power Reduction Mode.............................Page 2

Fuel Metering System Components ................Page 2

Quick-Connect Fittings.....................................Page 2

Fuel Supply Components (FCC System) .......Page 3

Fuel Pump Electrical Circuit ............................Page 4

Fuel Rail Assembly..........................................Page 4

Fuel Injectors.............................................Page 4

Pressure Regulator Assembly...................Page 5

Throttle Body Assembly...................................Page 5

Idle Air Control (IAC) Valve........................Page 6

Diagnosis ..............................................................Page 6

On-Board Service .................................................Page 6

Fuel Control On-Board Service .......................Page 7

Fuel Pressure Relief Procedure.......................Page 7

Flame Arrestor.................................................Page 7

Throttle Body Assembly...................................Page 8

Quick Connect Fitting(s) Service

(Metal Collar) ...................................................Page 9

Fuel Rail Assembly........................................Page 12

Fuel Injectors .................................................Page 15

Fuel Control Cell (FCC).................................Page 17

Fuel Pressure Regulator................................Page 19

Low-Pressure Fuel Pump ..............................Page 21

Fuel Pump Relay ...........................................Page 21

Torque Speciﬁ cations ........................................Page 22

MEFI 4 - PCM

3B - 2 Fuel Metering System 6.0L

General Description

Purpose

The function of the fuel metering system is to deliver the correct amount of fuel to the engine under all operating conditions. Fuel is delivered to the engine by individual fuel injectors mounted in the intake manifold near each cylinder.

Modes Of Operation

The ECM looks at inputs from several sensors to determine how much fuel to give the engine. The fuel is delivered under one of several conditions , called “modes .” All the “modes” are controlled by the ECM and are described below.

Starting Mode

When the ignition switch is turned to the crank position, the ECM turns the fuel pump relay “ON,” and the fuel pump builds up pressure. The ECM then checks the ECT, MAP and TP sensors, and determines the proper air/fuel ratio for starting. The ECM controls the amount of fuel delivered in the starting mode by changing how long the injectors are turned “ON” and “OFF.” This is done by “pulsing” the injectors for very short times.

Clear Flood Mode

If the engine ﬂ oods, it can be cleared by opening the throttle to 100% (wide open throttle) during cranking. The ECM then shuts down the fuel injectors so no fuel is delivered. The ECM holds this injector rate as long as the throttle stays at 100%, and the engine speed is below 300 RPM. If the throttle position becomes less than 100%, the ECM returns to the starting mode.

Run Mode

When the engine is ﬁ rst started and RPM is above 300 RPM, the system operates in the run mode. The ECM will calculate the desired air/fuel ratio based on these ECM inputs: RPM, ECT and MAP. Higher engine loads (MAP input) and colder engine temperatures (ECT input) require more fuel, or a richer air/fuel ratio.

Acceleration Mode

The ECM looks at rapid changes in TP sensor and MAP, and provides extra fuel by increasing the injector pulse width.

Fuel Cutoff Mode

No fuel is delivered by the injector when the ignition is “OFF,” to prevent dieseling. Also, injector pulses are not delivered if the ECM does not receive distributor reference pulses , which means the engine is not running. The fuel cutoff mode is also enabled at high engine RPM, as an overspeed protection for the engine. When fuel cutoff is in effect due to high RPM, injector pulses will resume after engine RPM drops below the maximum OEM RPM speciﬁ cation (Rev Limit).

engine power under certain conditions. Power reduction will disable one fuel injector driver when the engine speed goes above 2500 rpm, and enable the fuel injector driver when the engine speed drops below 1200 rpm. Power reduction may be active for the following conditions:

• Engine coolant temperature too high

• Low oil pressure

Fuel Metering System Components

The fuel metering system (Figure 3-1) is made up of the following parts:

Fuel supply components (fuel tank, pump, lines, ﬁ lter).

•

Fuel pump electrical circuit.

•

Fuel rail assembly, including fuel injectors

•

Throttle body assembly, including an IAC valve and

•

TP sensor.

Fuel Supply Components (FCC System)

Quick-Connect Fittings

Quick-Connect ﬁ ttings provide a simpliﬁ ed means of installing and connecting fuel system components. The ﬁ ttings consists of a unique female connector and a compatible male pipe end. O-rings, located inside the female connector, provide the fuel seal. Integral locking tabs inside the female connector hold the ﬁ ttings together.

The Fuel Control Cell (FCC) incorporates two (2) fuel pumps to provide uninterrupted ﬂ ow of fuel to your marine engine.

Fuel is fed into the FCC by a low-pressure, high volume electric fuel pump. This pump ﬂ ows fuel at a volume which exceeds the fuel ﬂ ow rate required of the high-pressure pump by engine demands.

The high pressure pump, mounted inside the FCC bowl, provides the necessary fuel pressure and volume to maintain proper engine performance, and always has an ample supply of fuel to meet the idle, cruise and acceleration fuel requirements of the engine.

The fuel pressure regulator, also located inside the FCC, controls fuel pressure and maintains a constant pressure across the fuel delivery system. Fuel not used b y the engine, excess fuel, is returned to the FCC canister.

The fuel delivered to the engine by the FCC is ﬁ ltered by a ﬁ lter and water separator element, which surrounds the high pressure pump inside the FCC bowl.

The fuel enters the FCC bowl from two (2) components, the low-pressure pump (initial input) and the fuel pressure regulator (unused recirculating). Fuel exits the FCC bowl at two (2) locations, the high-pressure output to the fuel rail and all excess fuel in the FCC bowl is routed back to the fuel tank via a return line.

Power Reduction Mode

Pow er reduction mode is a function of the ECM that reduces

MEFI 4 - PCM

6.0L Fuel Metering System 3B - 3

FUEL RAIL ASSEMBLY

ENGINE

PRESS.

REG.

FUEL

CONTROL

CELL

Fuel Control Cell Fuel System (Returnless Fuel Rail)

LOW-

PRESSURE

FUEL

PUMP

FUEL

FILTER

FUEL TANK

M4054P 2-12-04

Figure 3-1 - Fuel Metering System (Typical)

Figure 3-2 - Fuel Control Cell (FCC)

Figure 3-3 - Low Pressure Fuel Pump

MEFI 4 - PCM

3B - 4 Fuel Metering System 6.0L

Fuel Pump Electrical Circuit

When the ignition switch is turned “ON,” the ECM turns the fuel pump relay “ON” for two seconds causing the fuel pump(s) to pressurize the MEFI fuel system.

When the ignition switch is turned to the crank position, the ECM turns the fuel pump relay “ON” causing the fuel pump to run.

If the ECM does not receive ignition reference pulses (engine cranking or running), it shuts “OFF” the fuel pump relay, causing the fuel pump to stop.

An inoperative fuel pump relay will result in an “Engine Cranks But Will Not Run” condition.

Fuel Rail Assembly

The fuel rail (Figure 3-3) is mounted to the engine intake manifold, and performs several functions. It positions the injectors (3) in the intake manifold, distributes fuel evenly to the injectors, and integrates the fuel pressure regulator (2) into the fuel metering system.

Fuel Injectors

The Multec 2 fuel injector assembly is a solenoid operated device, controlled by the ECM, that meters pressurized fuel to a single engine cylinder. The ECM energizes the high-impedance (12.2 ohms) injector solenoid (1) to open a normally closed ball valve (2). This allows fuel to ﬂ ow into the top of the injector, past the ball valve and through a director plate (3) at the injector outlet. The director plate has four machined holes that control the fuel ﬂ ow, generating a spray of ﬁ nely atomized fuel at the injector tip. Fuel from the injector tip is directed at the intake valve, causing it to become further atomized and vaporized before entering the combustion chamber. An injector stuck partly open can cause a loss of pressure after engine shutdown. Consequently, long engine cranking times would be noticed on some engines.

Figure 3-3 - Fuel Rail Assembly

MEFI 4 - PCM

380659

351198

Figure 3-4 - Fuel Injector Assembly (Typical)

6.0L Fuel Metering System 3B - 5

Pressure Regulator Assembly

The pressure regulator is a diaphragm-operated relief valv e with fuel pump pressure on one side, and regulator spring pressure on the other side (Figure 3-5). The regulator’s function is to maintain a constant pressure differential across the injectors at all times.

With the ignition “ON,” engine “OFF”, fuel pressure at the pressure test connection should be 59-61 psi. If the pressure is too low, poor performance or a “no-start” may result. If pressure is too high, excessive odor may result.

Throttle Body Assembly

The throttle body assembly is attached to the intake manifold air plenum, and is used to control air ﬂ ow into the engine, thereby controlling engine output (Figure 3-6). The throttle plates within the throttle body are opened by the driver through the throttle controls. During engine idle, the throttle plates are closed, and air ﬂ ow control is handled by the Idle Air Control (IAC) valve, described below.

The throttle body also provides the location for mounting the TP sensor and for sensing changes in engine vacuum due to throttle plates position.

Figure 3-5 - Pressure Regulator Assembly (Typical)

meﬁ 4335

Figure 3-6 - Throttle Body Assembly (Typical)

MEFI 4 - PCM

3B - 6 Fuel Metering System 6.0L

Idle Air Control (IAC) Valve

The purpose of the IAC valve assembly (Figures 3-7 and 3-8) is to control engine idle speed, while preventing stalls due to changes in engine load.

The IAC valve, mounted to the throttle body, controls bypass air around the throttle plates (Figure 3-7). By moving a conical valve known as a pintle, IN, towards the seat (to decrease air ﬂ ow); or OUT, away from the seat (to increase air ﬂ ow), a controlled amount of air moves around the throttle plates. If RPM is too low, more air is bypassed around the throttle plates to increase it. If RPM is too high, less air is bypassed around the throttle plates to decrease it.

The ECM moves the IAC valve in small steps. These can be monitored by scan tool test equipment, which plugs into the Data Link Connector (DLC).

During idle, the proper position of the IAC valve is calculated by the ECM, based on battery voltage, coolant temperature and engine RPM. If the RPM drops below speciﬁ cation and the throttle plates are closed, the ECM senses a near stall condition and calculates a new valve position to prevent stalling.

Engine idle speed is a function of total air ﬂ ow into

•

the engine based on IAC valve pintle position plus throttle plates opening.

1

2

“Controlled” idle speed is programmed into the ECM,

•

which determines the correct IAC valve pintle position to maintain the desired idle speed for all engine operating conditions and loads.

The minimum air rate is set at the factory with a stop

•

screw . This setting allows enough air ﬂ ow by the throttle plates to cause the IAC valve pintle to be positioned at a calibrated number of steps (counts) from the seat, during “controlled” idle operation. This minimum air rate setting should not be altered by turning the stop screw or bending the linkage. Improper idle control will result.

➤

A

➤

B

➤

1 O-RING - IAC VALVE  2 IAC VALVE ATTACHING SCREW  A DISTANCE OF PINTLE EXTENSION  B DIAMETER OF PINTLE

Figure 3-8 - Flange Mounted Type IAC Valve

1

2

8-24-94

RS 22181

A

4

B

1 IDLE AIR CONTROL (IAC) VALVE  2 THROTTLE BODY ASSEMBLY  3 THROTTLE VALVE  4 IAC VALVE PINTLE  A ELECTRICAL INPUT SIGNAL  B AIR INLET

Figure 3-7 - IAC Valve Air Flow Diagram

3

8-25-94

RS 22193

Diagnosis

If the Engine Cranks But Will Not Run or immediately stalls, Table A-3 of the Diagnosis section must be used to determine if the failure is in the ignition system or the fuel system.

On-Board Service

Caution: To reduce the risk of ﬁ re and personal injury, relieve

fuel system pressure before servicing fuel system components.

After relieving fuel pressure, a small amount of fuel may be released when servicing fuel lines or connections. To reduce the chance of personal injury, cover fuel line ﬁ ttings with a shop towel before disconnecting to catch any fuel that may leak out. Place the towel in an approved container when disconnection is completed.

MEFI 4 - PCM

6.0L Fuel Metering System 3B - 7

Fuel Control On-Board Service

The following is general inf ormation required when working on the fuel system:

Always keep a dry chemical fire extinguisher near

•

the work area.

Fuel pipe fittings require new O-rings when

•

assembling.

Do not replace fuel pipe with fuel hose.

•

Always bleed off fuel pressure before servicing any

•

fuel system components.

Do not do any repairs on the fuel system until you

•

have read the instructions and checked the ﬁ gures relating the repair.

Observe all notices and cautions.

•

Fuel Pressure Relief Procedure

Tool Required: J 34730-1, Fuel Pressure Gauge

Important

• Refer to manufacturer’s warnings and cautions before proceeding.

1. Disconnect negative battery cable to avoid possible fuel discharge if an accidental attempt is made to start the engine.

2. Loosen fuel filler cap to relieve any tank vapor pressure.

3. Connect fuel pressure gauge J 34730-1 to fuel pressure connector assembly. Wrap a shop towel around ﬁ tting while connecting the gauge to avoid any spillage.

4. Install bleed hose into an approved container and open valve to bleed system pressure. Fuel connections are now safe for servicing.

5. Drain any fuel remaining in the gauge into an approved container.

Flame Arrestor

Remove or Disconnect

1. Flame arrestor retaining clamp.

2. Flame arrestor.

Inspect

• Flame arrestor element for dust, dirt or water. Replace if required.

Install or Connect

1. Flame arrestor to throttle body.

2. Flame arrestor retaining clamp to ﬂ ame arrestor.

MEFI 4 - PCM

3B - 8 Fuel Metering System 6.0L

Throttle Body Assembly Replacement

Remove or Disconnect

1. Disconnect the negative battery cable.

2. Remove the ﬂ ame arrestor clamp and ﬂ ame arrestor.

3. Disconnect the electrical connectors from the IAC valve and the TP sensor.

4. Disconnect the throttle cable.

5. Remove the throttle body assembly attaching nuts.

6. Remove the throttle body assembly and gasket.

7. Discard the gasket.

Important: To o prevent damage to the throttle valve, it is essential that the unit be placed on a holding ﬁ xture before performing service.

Notice: Stuff a rag in the intake manif old opening to prevent foreign material from entering the engine.

Inspect

• Manifold bore for loose parts and foreign material.

• Manifold mating surface for cleanliness or burrs that

could affect gasket sealing.

Important: Clean the throttle bore and valve deposits using carburetor cleaner and a parts cleaning brush. Do Not use a cleaner that contains methyl ethyl ketone, an extremely strong solvent, and not necessary for this type of deposit.

The throttle body metal parts may be cleaned in a cold, immersion type cleaner following the disassembly of the unit.

Notice: The TP sensor and IAC valve should not come in contact with solvent or cleaner, as they may be damaged. These components must be removed before immersion. Follow the procedures outlined in this section.

Caution: Safety glasses must be worn when using compressed air, as flying dirt particles may cause eye injury.

• Clean all metal parts thoroughly and blow dry with

compressed air. Be sure that all fuel and air passages are free of dirt and burrs.

• Inspect the mating surfaces for damage that could

affect gasket sealing.

• Inspect throttle body for cracks in casting.

• The thread-locking compound supplied in the service

repair kit is a small vial of thread-locking compound with directions for use. If this material is not available, use Loctite® 262 or equivalent.

Notice: When precoating the mounting bolts, do not use a higher strength locking compound than recommended. This may cause the removal of the bolts to be very difﬁ cult.

Throttle Body Assembly

Throttle Body Removal

MEFI 4 - PCM

Install or Connect

1. Install a new throttle body gasket.

2. Install the throttle body assembly and the throttle body assembly attaching nuts.

Tighten Tighten the throttle body assembly attaching nuts to

10 N.m (89 lb in).

3. Reconnect the throttle cable.

4. Reconnect the electrical connectors to the IAC valve and the TP sensor.

5. Install the ﬂ ame arrestor and clamp. Securely tighten the clamp.

6. Reconnect the negative battery cable.

6.0L Fuel Metering System 3B - 9

Quick Connect Fitting(s) Service

Tools Required

J 37088-A Tool Set, Fuel Line Quick-Connect Separator J 44581 Fuel Line Quick Connect Separator

Remove or Disconnect

1. Relieve the fuel system pressure before servicing any fuel system connection. Refer to Fuel Pressure

Relief Procedure.

2. Remove the retainer from the quick-connect ﬁ tting.

1238589

Caution: Wear safety glasses in order to avoid eye damage.

3. Blow dirt out of the ﬁ tting using compressed air.

4. Choose the correct tool from the tool set for the size of the ﬁ tting. Insert the tool into the female connector, then push inward in order to release the locking tabs.

12776

12780

MEFI 4 - PCM

3B - 10 Fuel Metering System 6.0L

5. Pull the connection apart.

6. Use a clean shop towel in order to wipe off the male pipe end.

7. Inspect both ends of the ﬁ tting for dirt and burrs. Clean or replace the components as required.

12782

Install or Connect

1. Apply a few drops of clean engine oil to the male pipe end.

MEFI 4 - PCM

12784

2. Push both sides of the ﬁ tting together in order to snap the retaining tabs into place.

12786

6.0L Fuel Metering System 3B - 11

3. Once installed, pull on both sides of the ﬁ tting in order to make sure the connection is secure.

12787

4. Install the retainer on to the quick-connect ﬁ tting.

1238589

MEFI 4 - PCM

3B - 12 Fuel Metering System 6.0L

Fuel Rail Assembly Replacement

Remove or Disconnect

1. Relieve the fuel system pressure. Refer to Fuel Pressure Relief Procedure.

2. Remove the engine cover.

3. Before removal, clean the fuel rail assembly with a spray type engine cleaner, GM X-30A or equivalent, if necessary. Follow the package instructions. Do not soak fuel rails in liquid cleaning solvent.

4. Disconnect the TP sensor harness connector.

5. Disconnect the IAC valve harness connector.

6. Identify the connectors to their corresponding injectors to ensure correct injector ﬁ ring order after reassembly.

7. Pull the top portion (2) of the injector connector up. Do not pull the top portion of the connector past the top

372749

of the white portion (1).

8. Push the tab (1) on the lower side of the injector connector in order to release the connector from the injector.

9. Repeat step 9 and step 10 for each injector connector.

MEFI 4 - PCM

372753

10. Disconnect the fuel feed line from the fuel rail. Refer to Quick Connect Fitting procedure in this section.

1238589

6.0L Fuel Metering System 3B - 13

12. Remove the fuel rail attaching bolts.

13. Remove the fuel rail assembly.

Notice:

• Remove the fuel rail assembly carefully in order to

prevent damage to the injector electrical connector terminals and the injector spray tips. Support the fuel rail after the fuel rail is removed in order to avoid damaging the fuel rail components.

• Cap the ﬁ ttings and plug the holes when servicing

the fuel system in order to prevent dirt and other contaminants from entering open pipes and passages.

1201536

14. Remove the injector lower O-ring seal (4) from the spray tip end of each injector (3).

15. Discard the O-ring seals.

Install or Connect

1. Lubricate the new lower injector O-ring seals (4) with clean engine oil.

2. Install the new O-ring seals (4) on the spray tip end of each injector (3).

351185

MEFI 4 - PCM

3B - 14 Fuel Metering System 6.0L

3. Install the fuel rail assembly to the intake manifold.

4. Apply a 5 mm (0.020 in) band of GM P/N 12345382 threadlock or equivalent to the threads of the fuel rail attaching bolts.

5. Install the fuel rail attaching bolts.

Tighten Tighten the fuel rail attaching bolts to 10 N.m (89

lb in).

1201536

6. Connect the fuel feed line to the fuel rail. Ref er to Quick Connect Fitting procedure in this section.

MEFI 4 - PCM

1238589

8. Connect the injector electrical connectors

• Install each connector on the proper injector in

order to ensure correct injector ﬁ ring order.

• Rotate the injectors as required in order to avoid

stretching the wire harness.

9. Reconnect the TP sensor harness connector.

10. Reconnect the IAC valve harness connector.

11. Install the engine cover.

12. Connect the negative battery cable.

13. Inspect for leaks.

13.1. Turn the ignition ON for 2 seconds.

13.2. Turn the ignition OFF for 10 seconds.

13.3. Turn the ignition ON.

13.4. Inspect for fuel leaks.

372749

6.0L Fuel Metering System 3B - 15

Fuel Injector Replacement

Remove or Disconnect

Important: The engine oil may be contaminated with fuel

if the fuel injectors are leaking.

1. Remove the fuel rail assembly. Refer to Fuel Rail

Assembly Replacement.

2. Remove the injector retainer clip (4).

3. Insert the fork of J 43013, the fuel injector assembly removal tool, between the fuel rail pod and the 3 protruding retaining clip ledges. Use a prying motion while inserting the tool in order to force the injector out of the fuel rail pod.

350543

4. Discard the injector retainer clip (1).

5. Remove the injector O-ring seals (2), (4) from both ends of the injector. Discard the O-ring seals.

Install or Connect

Important: When ordering new fuel injectors, be sure

to order the correct injector for the application being serviced.

The fuel injector assembly (1) is stamped with a part number identiﬁ cation (2). A four digit build date code (3) indicates the month (4), day (5), year (6) and the shift (7) that built the injector.

351185

351196

MEFI 4 - PCM

3B - 16 Fuel Metering System 6.0L

1. Lubricate the new O-ring seals (2), (4) with clean engine oil.

2. Install the new injector O-ring seals on the injector.

3. Install a new retainer clip (1) on the injector.

351185

4. Push the fuel injector (5) into the fuel rail injector socket with the electrical connector facing outwards. The retainer clip (4) locks on to a ﬂ ange on the fuel rail injector socket.

5. Install the fuel rail assembly. Refer to Fuel Rail Assembly Replacement procedure in this section.

MEFI 4 - PCM

350543

6.0L Fuel Metering System 3B - 17

Fuel Control Cell (FCC) Replacement - Screw On Bowl and Clamp On Bowl

Important

Fuel pressure must be relieved before servicing the

•

fuel pump.

Refer to “Fuel Pressure Relief Procedure.”

•

Remove or Disconnect

1. Negative battery cable.

2. Fuel pump electrical connector.

3. Inlet and outlet fuel line ﬁ ttings.

4. Fuel Control Cell (FCC) attaching bolts.

5. Fuel Control Cell (FCC).

Install or Connect

1. Fuel Control Cell (FCC).

2. Fuel Control Cell (FCC) attaching bolts.

3. Inlet and outlet fuel line ﬁ ttings.

4. Fuel pump electrical connector.

5. Negative battery cable.

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Turn the ignition switch back to the “ON” position and check for fuel leaks.

Fuel Control Cell (FCC) - Screw On Bowl

Fuel Control Cell (FCC) - Clamp On Bowl

MEFI 4 - PCM

3B - 18 Fuel Metering System 6.0L

Fuel Control Cell (FCC) - Screw On Bowl Drain Water (With Engine OFF)

1. Disconnect the two-wire electrical harness.

2. Hold the 3/4” jam nut located at the bottom of the FCC bowl with a wrench, remove the 3/16” allen plug and drain bowl contents into a suitable container.

Caution: Both fuel, which is explosive, and water will drain from the FCC bowl.

3. Apply pipe sealant suitable for use with gasoline to the threads fo the 3/16” allen plug.

4. Tighten the 3/16” allen plug while holding the 3/4” jam nut with a wrench.

5. Re-connect the two-wire electrical harness.

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Cycle the ignition several times to ﬁ ll the FCC bowl. Turn the ignition switch back to the “ON” position and check for fuel leaks.

FUEL

PRESSURE

REGULATOR

FUEL

PUMP

OR

"O"- RING

FUEL

FILTER

FUEL

PUMP

Fuel Control Cell (FCC) - Screw On Bowl Element Replacement (With Engine OFF)

1. Disconnect the two-wire electrical harness.

2. Hold the 3/4” jam nut located at the bottom of the FCC bowl with a wrench, remove the 3/16” allen plug and drain bowl contents into a suitable container.

Caution: Both fuel, which is explosive, and water will drain from the FCC bowl.

3. Using a strap type oil ﬁ lter wrench, remove the bowl by turning it counterclockwise as viewed from the bottom.

4. Slide bowl downward over the suspended ﬁ lter element. It may be necessary to pull the unit to one side or remove the fuel line from the feed pump to remove the bowl.

5. Remove the fuel ﬁ lter element from the suspended pump by gripping the fuel pump with one hand and pulling the ﬁ lter downward with the other hand.

6. Push on new ﬁ lter element over the electric pump.

7. Using a pick made of soft material, such as a toothpick, remove the old “O”-ring from inside the FCC bowl mounting head.

Caution: The mounting head “O”-ring groove may be damaged by using a sharp tool to remove this “O”-ring.

8. Lubricate the new “O”-ring with a light grease and install the new “O”-ring in the FCC head.

9. Grease taper and threads on the bowl and, by hand, thread the bowl into the FCC mounting head. Tighten the bowl ﬁ rmly back into the head with an oil ﬁ lter wrench.

10. Apply pipe sealant suitable with gasoline to the 3/16” allen plug.

11. Install and tighten the 3/16” allen plug while holding the 3/4” jam nut with a wrench.

12. Re-connect the two-wire electrical harness.

FUEL

BOWL

FUEL

DRAIN

MEFI 4 - PCM

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Cycle the ignition several times to ﬁ ll the FCC bowl. Turn the ignition switch back to the “ON” position and check for fuel leaks.

6.0L Fuel Metering System 3B - 19

Fuel Control Cell (FCC) - Clamp On Bowl Drain Water (With Engine OFF)

1. Disconnect the two-wire electrical harness.

2. Remove the 7/16” plug and drain the bowl contents into a suitable container.

Caution: Both fuel, which is explosive, and water will drain from the FCC bowl.

3. Apply pipe sealant, suitable for use with gasoline, to the threads fo the 7/16” plug.

4. Install and tighten the 7/16” plug securely.

5. Reconnect the two-wire electrical harness.

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Cycle the ignition several times to ﬁ ll the FCC bowl. Turn the ignition switch back to the “ON” position and check for fuel leaks.

6.0L 5.0/5.7L OR

O-RINGS

FUEL

PRESSURE

REGULATOR

Fuel Control Cell (FCC) - Clamp On Bowl Element Replacement (With Engine OFF)

1. Disconnect the two-wire electrical harness.

2. Remove the 7/16” plug and drain the bowl contents into a suitable container.

Caution: Both fuel, which is explosive, and water will drain from the FCC bowl.

3. Remove the canister retaining clamp.

4. Slide bowl downward over the suspended ﬁ lter element. It may be necessary to pull the unit to one side to remove the bowl.

5. Remove the fuel ﬁ lter element from the suspended pump by gripping the fuel pump with one hand and pulling the ﬁ lter downward with the other hand.

6. Push on new ﬁ lter element over the electric pump.

7. Using a pick made of soft material, such as a toothpick, remove the old “O”-rings from the FCC bowl mounting head.

Caution: The mounting head “O”-ring grooves may be damaged by using a sharp tool to remove these “O”-rings.

8. Lubricate the new “O”-rings with fuel resistant “O”-ring lubricant, and install the new “O”-rings on the FCC head.

9. Apply pipe sealant, suitable for use with gasoline, to the threads fo the 7/16” plug.

10. Install and tighten the 7/16” plug securely.

11. Install the bowl ﬁ rmly back onto the FCC head.

12. Install the canister retaining clamp and tighten securely.

13. Reconnect the two-wire electrical harness.

FUEL

PUMP

FUEL

FILTER

RETAINING

CLAMP

FUEL

BOWL

FUEL

DRAIN

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Cycle the ignition several times to ﬁ ll the FCC bowl. Turn the ignition switch back to the “ON” position and check for fuel leaks.

MEFI 4 - PCM

3B - 20 Fuel Metering System 6.0L

Fuel Pressure Regulator Replacement

Remove or Disconnect Important

Fuel pressure must be relieved before servicing the

•

fuel pump.

2

1

Refer to “Fuel Pressure Relief Procedure.”

•

1. Remove the FCC bowl. Refer to Fuel Control Cell Element Replacement steps 1-5.

2. Remove the two clamps (1).

3. Remove the fuel pressure regulator (2).

Install or Connect

4. Install the fuel pressure regulator (2).

5. Install two new clamps (1).

6. Push on a new ﬁ lter element over the electric pump.

7. Install the FCC bowl. Refer to Fuel Control Cell Element Replacement steps 7-12.

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Cycle the ignition several times to ﬁ ll the FCC bowl. Turn the ignition switch back to the “ON” position and check for fuel leaks.

MEFI 4 - PCM

6.0L Fuel Metering System 3B - 21

Low-Pressure Fuel Pump Replacement

Important

Fuel pressure must be relieved before servicing the

•

fuel pump.

Refer to “Fuel Pressure Relief Procedure.”

•

Remove or Disconnect

1. Negative battery cable.

2. Fuel pump electrical connector.

3. Inlet and outlet fuel line ﬁ ttings.

4. Fuel pump attaching bolts.

5. Fuel pump.

Install or Connect

1. Fuel pump.

2. Fuel pump attaching bolts.

3. Inlet and outlet fuel line ﬁ ttings.

4. Fuel pump electrical connector.

5. Negative battery cable.

Figure 3-3 - Low Pressure Fuel Pump

Inspect

Turn ignition switch to the “ON” position for 2 seconds,

•

then turn to the “OFF” position for 10 seconds. Turn the ignition switch back to the “ON” position and check for fuel leaks.

Fuel Pump Relay

Remove or Disconnect

1. Retainer, if installed.

2. Fuel pump relay electrical connector.

3. Fuel pump relay.

Important

The fuel pump relay is a electrical component. Do

•

Not soak in any liquid cleaner or solvent as damage may result.

Install or Connect

1. Fuel pump relay.

2. Fuel pump relay electrical connector.

3. Retainer clip.

PS 16871

Figure 3-18- Fuel Pump Relay

MEFI 4 - PCM

3B - 22 Fuel Metering System 6.0L

Torque Speciﬁ cations

Fastener Tightening Speciﬁ cations

Application N•m Lb Ft Lb In

Throttle Body Attaching Screws 15 11 IAC Valve Attaching Screws 3.2 28 Fuel Pressure Connector 13 115 Fuel Rail Attaching Screws 10 89

MEFI 4 - PCM

8.1L Fuel Metering System 3C - 1

Marine Electronic Fuel Injection (MEFI) Section 3C Fuel Metering System - 8.1L

This section describes how the fuel metering system operates, and provides a description of components used on the Marine Electronic Fuel Injection equipped engines. The fuel metering system information described in this section is limited to the 8.1L. All other systems will be detailed in a separate section.