Mitsubishi ENGINE ELECTRICAL SPECIFICATIONS

ENGINE

ELECTRICAL

CONTENTS

16-1

CHARGING SYSTEM 2................

GENERAL INFORMATION 2................

SERVICE SPECIFICATIONS 3..............

SPECIAL TOOL 3.........................

ON-VEHICLE SERVICE 4..................

Alternator Output Line Voltage Drop Test 4....

Output Current Test 5.......................

Regulated Voltage Test 7....................

Waveform Check Using An Analyzer 9........

Alternator Relay Continuity Check 10.........

ALTERNATOR 11..........................

STARTING SYSTEM 17................

GENERAL INFORMATION 17..............

SERVICE SPECIFICATIONS 17............

IGNITION SYSTEM 25.................

GENERAL INFORMATION 25..............

SERVICE SPECIFICATIONS 26............

ON-VEHICLE SERVICE 26................

Ignition Coil (With Built-in Power Transistor)

Check 26...................................

Spark Plug Check and Cleaning 27...........

Camshaft Position Sensor Check 28.........

Crank Angle Sensor Check 28...............

Detonation Sensor Check 28.................

IGNITION COIL 29.......................

CRANK ANGLE SENSOR 29..............

CAMSHAFT POSITION SENSOR 30.......

DETONATION SENSOR 31................

STARTER MOTOR 18.....................

16-2

ENGINE ELECTRICAL -

CHARGING SYSTEM

GENERAL INFORMATION

The charging system uses the alternator output to keep the battery charged at a constant level under various electrical loads.

Charging System

Voltage

OPERATION

Rotation of the excited field coil generates AC voltage in the stator. This alternating current is rectified through diodes to DC voltage having a waveform shown in the illustration at left.

Approx. 14.4 V

The average output voltage fluctuates slightly with the alternator load condition.

Time

When the ignition switch is turned on, current flows in the field coil and initial excitation of the field coil occurs. When the stator coil begins to generate power after the engine is started, the field coil is excited by the output current of the stator coil. The alternator output voltage rises as the field current increases and it falls as the field current decreases. When t he battery voltage (alternator S terminal voltage) reaches a regulated voltage

SYSTEM DIAGRAM

<4G9>

of approx. 14.4 V, the field current is cut off. When the battery voltage drops below t he regulated voltage, the voltage regulator regulates the output voltage to a constant level by controlling the field current. In addition, when the field current is constant, the alternator output voltage rises as the engine speed increases.

Stator coil

Field coil

Voltage regulator

Engine-ECU

G S

Charging warning lamp

Ignition switch

Battery

<4G6>

ENGINE ELECTRICAL -

Stator coil

Field coil

Voltage regulator

Charging System

Engine-ECU

Charging warning lamp

Ignition switch

16-3

Battery

ALTERNATOR SPECIFICATIONS

Items 4G9 4G6

Type Battery voltage sensing Battery voltage sensing

Rated output V/A 12/85 <Except cold climate zone>

12/100 <Cold climate zone>

Voltage regulator Electronic built-in type Electronic built-in type

12/100

SERVICE SPECIFICATIONS

Items Standard value Limit

Alternator output line voltage drop (at 30A) V - max. 0.3

Regulated voltage ambient -20_C 14.2- 15.4 temp. at voltage regulator V

20_C 13.9- 14.9 -

60_C 13.4- 14.6 -

80_C 13.1- 14.5 -

Output current - 70% of normal output current

Rotor coil resistance

Approx. 2 - 5 -

SPECIAL TOOL

Tool Number Name Use

MB991519 Alternator test

harness

Checking the alternator (S terminal voltage)

16-4

ENGINE ELECTRICAL -

Charging System

ON-VEHICLE SERVICE

ALTERNATOR OUTPUT LINE VOLTAGE DROP TEST

Alternator

Voltmeter

Terminal B

This test determines whether the wiring from the alternator “B” terminal to the battery (+) terminal (including the fusible line) is in a good condition or not.

1. Always be sure to check the following before the test.

Alternator installation

Alternator drive belt tension

Fusible link

Abnormal noise from the alternator while the engine is running

2. Turn the ignition switch off.

3. Disconnect the negative battery cable.

4. Disconnect the alternator output wire from the alternator “B” terminal and connect a DC test ammeter with a range of 0 - 100 A in series between the “B” terminal and the disconnected

Ammeter

Battery

output wire. (Connect the (+) lead of the ammeter to the “B” terminal, and then connect the (- ) lead of the ammeter to the disconnected output wire.)

NOTE An inductive-type ammeter which enables measurements to be taken without disconnecting the alternator output wire should be recommended. Using this equipment will lessen the possibility of a voltage drop caused by a loose “B” terminal connection.

5. Connect a digital-type voltmeter between the alternator “B” terminal and the battery (+) terminal. (Connect the (+) lead of the voltmeter to the “B” terminal and the connect the ( - ) lead of the voltmeter to the battery (+) cable.)

ENGINE ELECTRICAL -

Charging System

16-5

6. Reconnect the negative battery cable.

7. Connect a tachometer or the MUT-II.

8. Leave the hood open.

9. Start the engine.

10. With the engine running at 2,500 r/min, turn the headlamps and other lamps on a n d off to adjust the alternator load so that the value displayed on the ammeter is slightly above 30 A. Adjust the engine speed by gradually decreasing it until the value displayed on th e ammeter is 30 A. Take a reading of the value displayed on the voltmeter at this time.

Limit: max. 0.3 V

NOTE When the alternator output is high and the value displayed on the ammeter does not decrease until 30 A, set the value to 40 A. Read the value displayed on the voltmeter at this time. When the value range is 40 A, the limit is max.

0.4 V.

OUTPUT CURRENT TEST

11. If the value displayed on the voltmeter is above the limit value, there is probably a malfunction in the alternator output wire, so check the wiring between the alternator “B” terminal and the battery (+) terminal (including fusible link). If a terminal is not sufficiently tight or if the harness has become discolored due to overheating, repair and then test again.

12. After the test, run the engine at idle.

13. Turn off all lamps and the ignition switch.

14. Remove the tachometer or the MUT-II.

15. Disconnect the negative battery cable.

16. Disconnect the ammeter an d voltmeter.

17. Connect the alternator output wire to the alternator “B” terminal.

18. Connect the negative battery cable.

Ignition switch

Battery

Charging warning lamp

Alternator relay

Voltmeter

Ammeter

+-+-

Engine

-ECU

Load

Alternator

16-6

ENGINE ELECTRICAL -

Charging System

This test determines whether the alternator output current is normal.

1. Before the test, always be sure to check the following.

D Alternator installation D Battery

NOTE The battery should be slightly discharged. The load needed by a fully-charged battery is insufficient for an accurate test.

D Alternator drive belt tension D Fusible link D Abnormal noise from the alternator while

the engine is running.

2. Turn the ignition switch off.

3. Disconnect the negative battery cable.

4. Disconnect the alternator output wire from the alternator “B” terminal. Connect a DC test ammeter with a range of 0 - 100 A in series between the “B” terminal and the disconnected output wire. (Connect the (+) lead of the ammeter to the “B” terminal. Connect the ( - ) lead of the ammeter to the disconnected output wire.)

Caution Never use clips but tighten bolts and nuts to connect the line. Otherwise loose connections (e.g. using clips) will lead to a serious accident because of high current.

NOTE An inductive-type ammeter which enables measurements to be taken without disconnecting the alternator output wire should be recommended.

5. Connect a voltmeter with a range of 0- 20 V between the alternator “B” terminal and the earth. (Connect the (+) lead of the voltmeter to the “B” terminal, and then connect the (- ) lead of the voltmeter to the earth.)

6. Connect the negative battery cable.

7. Connect a tachometer or the MUT-II.

8. Leave the hood open.

9. Check that the reading on the voltmeter is equal to the battery voltage.

NOTE If the voltage is 0 V, the cause is probably an open circuit in the wire or fusible link between the alternator “B” terminal and the battery (+) terminal.

10. Turn the light switch on to turn on headlamps and then start the engine.

11. Immediately after setting the headlamps to high beam and turning the heater blower switch to the high revolution position, increase the engine speed to 2,500 r/min and read the maximum current output value displayed on the ammeter.

Limit: 70% of normal current output

NOTE D For the nominal current output, refer to the

Alternator Specifications.

D Because the current from the battery will

soon drop after the engine is started, the above step should be carried out as quickly as possible in order to obtain the maximum current output value.

D The current output value will depend on

the electrical load and the temperature of the alternator body.

D If the electrical load is small while testing,

the specified level of current may not be output even though the alternator is normal. In such cases, increase the electrical load by leaving the headlamps turned on for some time to discharge the battery or by using the lighting system in another vehicle, and then test again.

D The specified level of current also may not

be output if the temperature of the alternator body or the ambient temperature is too high. In such cases, cool the alternator and then test again.

12. The reading on the ammeter should be above the limit value. If the reading is below t he limit value and the alternator output wire is normal, remove the alternator from the engine and check the alternator.

13. Run the engine at idle after the test.

14. Turn the ignition switch off.

15. Remove the tachometer or the MUT-II.

16. Disconnect the negative battery cable.

17. Disconnect the ammeter an d voltmeter.

18. Connect the alternator output wire to the alternator “B” terminal.

19. Connect the negative battery cable.

ENGINE ELECTRICAL -

REGULATED VOLTAGE TEST

Ignition switch

Charging warning lamp

Alternator relay

EngineECU

MB991519

Charging System

Alternator

L S

Yellow

Ammeter

16-7

Load

Battery

Voltmeter

This test determines whether the voltage regulator is correctly controlling the alternator output voltage.

1. Always be sure to check the following before the test.

Alternator installation

Check that the battery installed in the vehicle is fully charged.

Alternator drive belt tension

Fusible link

Abnormal noise from the alternator while the engine is running

2. Turn the ignition switch off.

3. Disconnect the negative battery cable.

4. Use the special tool (Alternator test harness: MB991519) to connect a digital voltmeter between the alternator S terminal and earth. (Connect the (+) lead of the voltmeter to the ”S” terminal, and then connect the (-) lead of the voltmeter to a secure earth or to the battery (-) terminal.)

5. Disconnect the alternator output wire from the alternator “B” terminal.

6. Connect a DC test ammeter with a range of 0 - 100 A in series between the “B” terminal and the disconnected output wire. (Connect the (+) lead of the ammeter to the “B” terminal. Connect the ( - ) lead of the ammeter to the disconnected output wire.)

7. Reconnect the negative battery cable.

8. Connect a tachometer or the MUT-II.

9. Turn the ignition switch to the ON position a nd check that the reading on the voltmeter is equal to the battery voltage.

NOTE If the voltage is 0 V, the cause is probably an open circuit in the wire or fusible link between the alternator “S” terminal and the battery (+) terminal.

10. Turn all lamps and accessories off.

11. Start the engine.

12. Increase the engine speed to 2,500 r/min.

13. Read the value displayed on the voltmeter when the alternator output current alternator becomes 10 A or less.

16-8

ENGINE ELECTRICAL -

Charging System

14. If the voltage reading conforms to th e value in the voltage regulation, then the voltage regulator is operating normally. If the voltage is not within the standard value, there is a malfunction of the voltage regulator or of the alternator.

15. After the test, lower the engine speed to the idle speed.

16. Turn the ignition switch off.

Voltage Regulation Table Standard value:

Inspection terminal Voltage regulator ambient temperature_C Voltage V

Terminal “S” -20 14.2- 15.4

20 13.9- 14.9

60 13.4- 14.6

80 13.1- 14.5

17. Remove the tachometer or the MUT-II.

18. Disconnect the negative battery cable.

19. Disconnect the ammeter an d voltmeter.

20. Connect the alternator output wire to the alternator “B” terminal.

21. Remove the special tool, and return the connector to the original condition.

22. Connect the negative battery cable.

ENGINE ELECTRICAL -

Charging System

16-9

WAVEFORM CHECK USING AN ANALYZER

MEASUREMENT METHOD

Alternator

Special patterns pickup

Analyzer

Connect the analyzer special patterns pick-up to th e alternator B terminal.

B terminal

STANDARD WAVEFORM Observation Conditions

FUNCTION SPECIAL PATTERNS

PATTERN HEIGHT VARIABLE

VARIABLE knob Adjust while viewing the waveform.

PATTERN SELECTOR RASTER

Engine speed Curb idle speed

Voltage at alternator B terminal

0.4

0.2

- 0.2

- 0.4

Time

NOTE The voltage waveform of the alternator B terminal can undulate as shown at left. This waveform is produced when the regulator operates according to fluctuations in the alternator load (current), and is normal for the alternator. In addition, when the voltage waveform reaches an excessively high value (approx. 2 V or higher at idle), it often indicates an open circuit due to a brown fuse between alternator B terminal and battery, but not a defective alternator.

16-10

ENGINE ELECTRICAL -

Charging System

EXAMPLES OF ABNORMAL WAVEFORMS

NOTE

1. The size of the waveform patterns differs largely, depending on the adjustment of the variable knob on the analyzer.

2. Identification of abnormal waveforms is easier when there is a large output current (regulator is not operating). (Waveforms can be observed when the headlamps are illuminated.)

3. Check the conditions of the charging warning lamp (illuminated/not illuminated). Also, check the charging system totally.

Abnormal waveforms Problem

cause

Open diode

Short in diode

Broken wire in stator coil

Example 1

Example 2

Example 3

Abnormal waveforms Problem

cause

Short in stator coil

Open supplementary diode

Example 4

Example 5

At this time, the charging warning lamp is illuminated.

Alternator relay

ALTERNATOR RELAY CONTINUITY CHECK

1. Remove the alternator relay from the relay box inside the engine compartment.

2. Set the analogue-type circuit tester to the W range and check that there is continuity when the (+) terminal of the tester is connected to terminal 2 of the alternator relay and the ( - ) terminal is connected to terminal 4.

3. Next, check that there is no continuity when the (+) terminal is connected to terminal 4 and the ( - ) terminal is connected to terminal 2.

4. If defect is found in steps 2 and 3 above, replace the alternator relay.

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