Page 1
®
CP7818 – Fuel Pressure Tester Kit
INSTRUCTIONS
•
Fuel pressure testing involves some contact with pressurized fuel.
•
Do not use the Fuel Pressure Tester Kit on Diesel or Flex Fuel engines.
•
Only use the Fuel Pressure Tester Kit on Gasoline powered engines.
•
Helps diagnose driveability problems due to abnormally high or low fuel pressure.
VEHICLE APPLICATION LIST
The Fuel Pressure Tester Kit works on most domestic fuel injected vehicles
having a schrader valve test port on the fuel rail. This includes Ford
high pressure central fuel injection and GM, Ford, and Chrysler multiport fuel injection. Multi-port means one fuel injector per cylinder.
Domestic FORD,
LINCOLN, MERCURY
High Pressure Central Fuel Injected
1981-86 Country Squire, Crown
1985-86 Mustang & Capri
1985-87 Thunderbird & Cougar
1981-85 Continental, Town Car, Mark VI
1980 Versailles
Most Multi-Port Fuel Injected Vehicles
Not Including:
1.3L Festiva & Aspire
1.6L Capri
1.8L Escort & Tracer
2.0L, 2.2L & 2.5L Probe
3.0L Villager
(CFI) Vehicles
Victoria, LTD, Colony Park,
Grand Marquis, & Marquis
& Mark VII
1983 to 1996.
Year Engine 8th VIN Digit
1995-96 2.0L C or Y
1984-93 2.2L Turbo E
1995-96 2.4L X
1984-92 2.5L Turbo J
1987-96 3.3L R
1993-96 3.5L F
1987-93 3.8L L
Multi-Port Fuel Injected Trucks & Vans
Year Engine 8th VIN Digit
1996 2.4L B
1989 2.5L Turbo J
1992-96 3.3L R
1994-96 3.8L L
1992-96* 3.9L X
1992-96* 5.2L Y
1993-96 5.9L 5 or Z
1994-96 8.0L W
Domestic GENERAL MOTORS
Most Multi-Port Fuel Injected Vehicles
1984 to 1996.
Not Including:
1988 1.6L Nova
1988-89 1.5L Spectrum
1987-90 Sprint Turbo
* Some 1996 engines may not have a schrader valve fuel rail test port.
Year Engine 8th VIN Digit
1991-95 2.5L P
1987-96* 4.0L S
1993-96* 5.2L Y
Year Engine 8th VIN Digit
1995-96 2.0L Y
1993-96 3.3L T
1993-96 3.5L F
Domestic CHRYSLER,
PLYMOUTH, DODGE
Multi-Port Fuel Injected
Passenger Vehicles
JEEP
Multi-Port Fuel Injected Vehicles
Domestic EAGLE
Multi-Port Fuel Injected Vehicles
Vehicle Service Information:
The following is a list of publishers who have manuals containing electronic fuel injection system
information. Some manuals may be available at auto parts stores, your local dealer, or your local
public library. For others, you need to write for availability and prices, specifying the make,
model and year of your vehicle.
Aftermarket Vehicle Service Manuals:
Chilton Book Company
Chilton Way
Radnor, PA 19089
Haynes Publications
861 Lawrence Drive
Newbury Park, CA 91320
Cordura Publications
Mitchell Manuals, Inc.
Post Office Box 26260
San Diego, CA 92126
Motor’s Auto Repair Manual
Hearst Company
250 W. 55th Street
Vehicle Service Manuals from
General Motors Corporation:
Buick
Tuar Company
Post Office Box 354
Flint, MI 48501
Oldsmobile
Lansing Lithographers
Post Office Box 23188
Lansing, MI 48909
Cadillac, Chevrolet, Pontiac
Helm Incorporated
Post Office Box 07130
Detroit, MI 48207
New York, NY 10019
Vehicle Service Manuals from
Vehicle Service Manuals from
Ford Motor Company:
Ford Publication Department
Helm Incorporated
Post Office Box 07150
Detroit, MI 48207
Customer Service
For product information or customer service
please call 1-800-ACTRON-7 (1-800-228-7667)
Monday through Friday, between 8:30 a.m. and
4:30 p.m. Eastern time or fax anytime at
(216) 651-2388.
Actron can also be reached by Email or on the
Internet.
Email address: sunpro@actron.com
Chrysler Corporation:
Chrysler Corporation
Dyment Distribution Service
Service Publication
12200 Alameda Drive
Strongsville, Ohio 44136
One Year Warranty
If within one year from the date of
purchase this equipment fails due
to defect in materials or workmanship, return it to Actron and Actron
will repair it free of charge.
This warranty gives you specific
legalights, and you may also have
other rights which may vary from
state to state.
Internet home page: http://www.actron.com
Note
All information, illustrations and specifications contained in this manual are based on the latest
information available from industry sources at the time of publication. No warranty (expressed
or implied) can be made for its accuracy or completeness, nor is any responsibility assumed
by Actron Manufacturing Co. or anyone connected with it for loss or damages suffered through
reliance on any information contained in this manual or misuse of accompanying product.
Actron Manufacturing Co. reserves the right to make changes at any time to this manual or
accompanying product without obligation to notify any person or organization of such changes.
Page 2
Instructions for Fuel
Pressure T ester Kit
Safety Precautions
To prevent accidents that could result in
serious injury and/or damage to your vehicle
or test equipment, carefully follow these
safety rules and test procedures at all times
when working on vehicles.
• Always wear approved eye protection.
• Never use Fuel Pressure Tester Kit on
Diesel or Flex Fuel engines!
• Never attach Fuel Pressure Tester to any
place other than the fuel rail test port. Do
not confuse Air Conditioning schrader
valves with the fuel rail test port.
• Never attach or remove Fuel Pressure
Tester Kit from fuel rail test port with the
ignition key on.
• Always place end of 6 ft. bleed-off hose in
an approved container for fuel during testing and when bleeding off fuel pressure.
• Never smoke or have open flames near
vehicle. Vapors from fuel and charging battery are highly flammable and explosive.
• Never permit fuel to spill on hot engine
parts. If a spill or leak occurs, immediately
turn ignition key off, and clean up fuel.
• Only use the Fuel Pressure Tester Kit for
measuring fuel pressure on vehicles having
schrader valves as their fuel rail test port. Do
not use this kit for any other purpose!
• Always operate the vehicle in a well ventilated area. Do not inhale exhaust gases or
fuel vapors - they are very hazardous!
• Always keep yourself, tools and test equipment away from all moving or hot engine
parts.
• Always make sure the vehicle is in PARK
(Automatic transmission) or NEUTRAL
(manual transmission) and that the park-
ing brake is firmly set. Block the drive
wheels.
• Never lay tools on vehicle battery. You
may short the terminals together causing
harm to yourself, the tools or the battery.
• Never leave vehicle unattended while running tests.
• Always keep a fire extinguisher suitable for
fuel/electrical/chemical fires handy.
• Always use extreme caution when working
around the ignition coil, distributor cap, ignition wires, and spark plugs. These compo-
nents contain High Voltage when the engine is running.
• Complete all Pre-Testing Checks before
beginning fuel pressure testing.
• Always follow vehicle manufacturer’s warnings, cautions and service procedures.
CAUTION:
Some vehicles are equipped with safety
air bags. You
must
follow vehicle service
manual cautions when working around
the air bag components or wiring. If the
cautions are not followed, the air bag
may open up unexpectedly, resulting in
personal injury. Note that the air bag can
still open up several minutes after the
ignition key is off (or even if the vehicle
battery is disconnected) because of a
special energy reserve module.
Fuel Pressure Tester
Description
1. Dial Face: Measurement scale that
shows amount of fuel pressure present
in fuel system.
2. Pressure Relief Button: Used to re-
lieve fuel pressure in the gauge hose
before disconnecting the gauge hose
from the fuel rail.
3. Bleed-Off Hose: A 6-ft. hose that bleeds
off fuel pressure when the pressure relief
40
60
300
400
200
500
20
100
psi
80
600
700
kPa
100
3
4
Fig. 1
1
2
6
5
button is pressed. Never use a bleed-off
hose shorter than 6 ft.
Important: Always make sure end of
bleed-off hose is in an approved container for fuel at all times during testing
and when bleeding off fuel pressure!!
4. Gauge Hose: Hose that carries fuel to
the gauge so that pressure can be measured.
5. GM/Chrysler Test Port Adapter: This
adapter is used to connect the gauge
hose to GM and Chrysler vehicles
equipped with a schrader valve test
port on the fuel rail.
6. Ford Test Port Adapter: This adapter
is used to connect the gauge hose to
Ford vehicles equipped with a
schrader valve test port on the fuel
rail.
Fuel Injection System Theory
There are two basic types of fuel injection
systems currently being used by GM, Ford,
and Chrysler. The first type is called “port”
or “multi-port” fuel injection. In this system,
the fuel injectors spray fuel directly into the
intake manifold behind the intake
valve. These systems typically have
one fuel injector per
Fig. 3
FUEL
INJECTORS
FUEL RAIL
TEST PORT
cylinder. The second type is commonly called Throttle
Body Injection (TBI)
for GM and Chrysler
vehicles or Central
Fuel Injection (CFI)
for Ford vehicles.
These systems use
VACUUM
PORT
one or two fuel injectors mounted on top
of the intake manifold. They spray fuel
into the throttle body
similarly to a conventional carburetor.
See Fig. 2 for illustrations of both types
of fuel systems.
Fuel System Components
Before doing any fuel pressure testing, it is a
good idea to understand how fuel system
components work and how they relate to one
another. The fuel pump pumps fuel from the
fuel tank to the fuel pressure regulator and
fuel injectors. The fuel pressure regulator
Fig. 2
FUEL
INJECTORS
FUEL PRESSURE
REGULATOR
Ford CFI
Throttle Body
FUEL
INJECTORS
PRESSURE
LINE
FUEL RAIL
TEST PORT
RETURN LINE
FUEL PRESSURE
REGULATOR
GM Multi-Port
Fuel Injection
FUEL PRESSURE
REGULATOR
FUEL INJECTORS
FUEL
TANK
FUEL FILTER
FUEL PUMP
FUEL INJECTORS
FUEL
RAIL
divides fuel between the pressure line and
the return line. The fuel in the pressure line
goes to the fuel injectors, while the fuel in the
return line is returned to the fuel tank.
Fig. 3 shows the orientation of fuel system
components in a typical “port” fuel injection
system.
PRESSURE
LINE
RETURN
LINE
FUEL
RAIL
PRESSURE
LINE
RETURN
LINE
FUEL PUMP FILTER
Page 3
Fuel Tank: A large container that holds your
vehicles supply of fuel.
Fuel Pump Filter: A filter that is usually
located in the fuel tank. Its function is to
prevent foreign particles from reaching the
fuel pump. A clogged or restricted fuel pump
filter can cause low fuel pressure readings.
When replacing a fuel pump it is a good idea
to clean or replace the fuel pump filter.
Fuel Pump: An electric motor that pumps
fuel into the fuel system at a constant pressure. It is mounted in the fuel tank or on the
frame. Some vehicles have more than one
fuel pump.
Return Line: Path way for excess fuel to
return to the fuel tank.
Pressure Line: A pressurized fuel line that
carries fuel from the fuel tank to the fuel
injectors.
Fuel Filter: A filter that is located in-line with
the pressure line. Its function is to prevent
foreign particles from reaching the fuel injectors. A clogged or restricted fuel filter can
also cause low fuel pressure readings. This
is the only fuel system component that requires periodic replacement. Refer to vehicle
owners manual for replacement interval.
Fuel Rail Test Port: A schrader valve located on the fuel rail (Fig. 4) that allows easy
connection of a fuel pressure gauge to measure fuel pressure. Do not confuse this valve
with the schrader valves that are used for
recharging air conditioning systems.
Fuel Pressure Regulator: The fuel pressure regulator (Fig. 5) is connected across
the pressure line and return line. It contains
a spring loaded valve assembly that opens
to allow fuel to move into the return line,
when the pressure line fuel pressure is exceeded. It is used to keep a constant fuel
pressure drop across the fuel injectors. Some
fuel pressure regulators have a vacuum port
so fuel pressure can be adjusted based on
engine load. These are commonly called
vacuum actuated (compensated) fuel pressure regulators. A leaking fuel pressure regulator can cause low fuel pressure readings
and hard starting problems.
Fuel Rail: The fuel rail assembly is bolted to
the intake manifold. Its purpose is to hold the
fuel injectors in place and to deliver pressurized fuel to the fuel injectors.
Fuel Injectors: A precision valve that is
controlled by a solenoid. Fuel injection is
controlled by the amount of fuel pressure,
Fig. 4
FUEL RAIL TEST PORT
FUEL
RAIL
PROTECTIVE
CAP
Typical
GM Multi-Port Fuel Injection System
Fig. 5
RETURN
LINE
VACUUM PORT
PRESSURE
LINE
Vacuum Actuated (Compensated)
Fuel Pressure Regulator
and the size and duration of the valve opening. Fuel injectors contain a filter used to
prevent very small particles from clogging
the valve. Leaking fuel injectors will cause
fuel pressure to slowly decrease when the
ignition key is on and engine is off.
Pre-Testing Checks
1. Read Safety Precautions.
2. Do a thorough visual and “hands-on” in-
spection of the engine and fuel system.
Look for loose or cracked electrical wiring, battery cables, ignition wires, and
fuel or vacuum lines.
3. Verify that the battery is fully charged and
fuel tank has an adequate supply of fuel.
4. Verify that the inertia switch on certain
Ford/Lincoln/Mercury vehicles has not
been tripped. (The inertia switch is usually located in the trunk.)
5. Verify that all fuel system fuses are good.
6. Verify fuel vapor recovery system and
gas cap are in good condition.
7. Verify that manifold vacuum is within
manufacturers specification which is typically 18-20 in. at idle.
8. Look for fuel leaks and wipe up any spilled
fuel immediately.
9. If engine will not
start, check igni-
Fig. 6
tion system for
spark. If no ignition
spark is present,
refer to vehicle service manual for No
Start Diagnostics.
END OF
BLEED-OFF
Fuel Pressure
Testing
Procedures
This test procedure
explains how to make
HOSE MUST
BE PLACED IN
AN
APPROVED
FUEL
CONTAINER
fuel pressure measurements on vehicles
while the ignition key
is on and while the engine is at idle. The
procedure also explains the safest way to
connect and disconnect the fuel pressure
tester kit from vehicles equipped with
schrader valves as their fuel rail test ports. If
the fuel pressure readings measured in this
test procedure are not within your vehicles
manufacturing specification, then you must
use your vehicle service manual along with
the fuel pressure tester kit to service the
problem. This test procedure does not contain any vehicle specific diagnostics.
1. Read all SAFETY PRECAUTIONS and
PRE-TESTING CHECKS.
2. Apply a lightweight household oil to
the rubber “O” rings inside both test
port adapters.
3. Turn Ignition Key OFF.
4. Locate fuel rail test port and remove
protective cap. (See Fig. 4.)
For Ford/Lincoln/Mercury Vehicles...
• Screw Ford test port adapter to fuel rail
test port until finger tight.
• Screw GM/Chrysler test port adapter to
the Ford test port adapter until finger
tight.
For GM/Chrysler Vehicles...
• Screw GM/Chrysler test port adapter to
fuel rail test port until finger tight.
Note: Always wrap a shop rag around
fuel rail test port when attaching test port
adapters. This is a precaution in case a
small amount of fuel leaks out while attaching adapters.
5. Place end of 6 ft. bleed-off hose in an
approved container for fuel.
40
60
300
400
200
500
20
80
100
600
700
kPa
100
psi
FUEL RAIL
SHOP
TEST PORT
RAG
Bleed-off hose must remain in container
until testing is complete.
6. Turn all accessories OFF. (i.e. Radio,
A/C, Blower Fan, Headlights, Windshield Wipers...)
7. Turn ignition key ON.
Do the following checks...
• Listen for fuel pump. Pump should run
for approximately 2 seconds.
• Check fuel system for leaks. If leaks
found, turn ignition key OFF and wipe
up fuel immediately!
• Read fuel pressure from dial face. Pres-
sure should rise to manufacturers specification and hold steady even after fuel
pump stops running. Refer to vehicle
service manual for fuel pressure specifications.
• If fuel pressure is not within manufac-
turers specification, than service vehicle according to vehicle service
manual.
• When repair is completed and key-on-
engine-off fuel pressure is now within
manufacturers specification, then proceed to Step 8.
• For instructions on how to safely dis-
connect the Fuel Pressure Tester Kit
from the fuel rail test port, proceed to
Step 9.
8. Start engine – Let idle.
• If your vehicles fuel system uses a
vacuum actuated (compensated) fuel
pressure regulator then fuel pressure
should drop approximately 3-10 psi, depending on manifold vacuum.
Page 4
• If your vehicles fuel system uses a fuel
®
pressure regulator without a vacuum
port than fuel pressure should remain
constant during both key-on-engine-off
and idle.
• Read fuel pressure from dial face.
• If fuel pressure is not within manufacturers specification, than service vehicle according to vehicle service
manual.
• When repair is completed and idle fuel
pressure is now within manufacturers
specification, then proceed to Step 9.
• To safely disconnect the Fuel Pressure
Tester Kit from the fuel rail test port and
perform repairs at a later time, proceed
to Step 9.
9. Turn Ignition Key OFF.
10.Verify that 6 ft. bleed-off hose is still in
an approved container for fuel.
11.Fully DEPRESS and HOLD the pressure relief button until dial face pointer
is resting on stop pin.
12.Shake bleed-off hose to make sure
that all fuel went into approved container.
13.Remove gauge hose from fuel rail test
port.
For Ford/Lincoln/Mercury Vehicles...
• Wrap a shop rag around fuel rail test
port in case a small amount of fuel drips
out while unscrewing test port adapters.
• Unscrew GM/Chrysler test port adapter
from Ford test port adapter.
• Wrap a shop rag around GM/Chrysler
test port adapter so any fuel dripping
from gauge hose is absorbed.
• Remove bleed-off hose from approved
fuel container and hold gauge hose over
container so any remaining fuel will drip
into container.
• Unscrew Ford test port adapter from
fuel rail test port.
For GM/Chrysler Vehicles...
• Wrap a shop rag around fuel rail test
port in case a small amount of fuel drips
out while unscrewing test port adapters.
• Unscrew GM/Chrysler test port adapter
from fuel rail test port.
• Wrap a shop rag around GM/Chrysler
test port adapter so any fuel dripping
from gauge hose is absorbed.
• Remove bleed-off hose from approved
fuel container and hold gauge hose over
container so any remaining fuel will drip
into container.
14.Store shop rags in an approved container so they cannot cause personal
injury or a hazardous situation.
15.Store Fuel Pressure Tester in a well
ventilated area where it cannot cause
personal injury or a hazardous situation.
General Fuel Pressure
Diagnostics
Fuel pressure checking is an essential part
of fuel injection system troubleshooting. High
fuel pressure will make an engine run rich,
while low fuel pressure will make an engine
run lean or not at all.
Fuel pressure readings that are higher than
manufacturers specifications are generally
caused by a problem in the return line fuel
components. Conversely, fuel pressure readings that are lower than manufacturers specifications are generally caused by a problem
in the pressure line fuel components.
If fuel pressure readings are not within manufacturers specifications, then refer to a vehicle service manual for step-by-step diagnostic procedures that will pinpoint the faulty
component for your specific vehicle.
Possible causes of high fuel pressure readings are the following:
• Faulty fuel pressure regulator.
• Restriction in return line.
• Faulty fuel line couplings at fuel tank.
Possible causes of low fuel pressure readings are the following:
• Clogged or restricted fuel filter.
• Restriction in pressure line.
• Faulty fuel pump.
• Faulty fuel pump relay.
• Bad fuel pump fuse.
• Faulty fuel pump wiring.
• Clogged or restricted fuel pump filter.
• Faulty fuel pressure regulator.
• Leaking fuel injectors.
• Faulty fuel line couplings at fuel tank.
Care and Maintenance
Apply a lightweight household oil to the rubber “O” rings inside both the GM/Chrysler
and Ford test port adapters before each use.
ACTRON MANUFACTURING CO.
9999 Walford Avenue
Cleveland, Ohio 44102
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