Mitsubishi Galant 9G. Manual — part 360

IGNITION SYSTEM

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ENGINE ELECTRICAL

16-36

IGNITION SYSTEM

GENERAL DESCRIPTION

M1163000100528

<2.4L ENGINE>

This system is provided with four ignition coils with
built-in ignition power transistors for each of the cylin-
ders.
Interruption of the primary current flowing in the pri-
mary side of ignition coil generates a high voltage in
the secondary side of ignition coil.
The powertrain control module (PCM) controls the
four ignition power transistors to turn them alter-
nately ON and OFF. This causes the primary cur-
rents in the ignition coils to be alternately interrupted
and allowed to flow to fire the cylinders in the order
1-3-4-2.

The PCM determines which ignition coil should be
controlled by means of the signals from the camshaft
position sensor which is incorporated in the camshaft
and from the crankshaft position sensor which is
incorporated in the crankshaft.
It also detects the crankshaft position to provide igni-
tion at the most appropriate timing in response to the
engine operation conditions.
When the engine is cold or operated at high alti-
tudes, the ignition timing is slightly advanced to pro-
vide optimum performance.

<3.8L ENGINE>

This system is provided with six ignition coils with
built-in ignition power transistors for each of the cylin-
ders.
Interruption of the primary current flowing in the pri-
mary side of ignition coil generates a high voltage in
the secondary side of ignition coil.
The powertrain control module (PCM) controls the
three ignition power transistors to turn them alter-
nately ON and OFF. This causes the primary cur-
rents in the ignition coils to be alternately interrupted
and allowed to flow to fire the cylinders in the order
1-2-3-4-5-6.

The PCM determines which ignition coil should be
controlled by means of the signals from the camshaft
position sensor which is incorporated in the camshaft
and from the crankshaft position sensor which is
incorporated in the crankshaft.
It also detects the crankshaft position to provide igni-
tion at the most appropriate timing in response to the
engine operation conditions.
When the engine is cold or operated at high alti-
tudes, the ignition timing is slightly advanced to pro-
vide optimum performance.

AK304112AB

PCM

IGNITION SWITCH

IGNITION COIL

SPARK PLUG

CYLINDER NO.

BATTERY

1

2

3

4

INTAKE AIR TEMPERATURE SENSOR

CAMSHAFT POSITION SENSOR

CRANKSHAFT POSITION SENSOR

TRANSMISSION RANGE SWITCH

IGNITION SWITCH-ST

KNOCK SENSOR

ENGINE COOLANT TEMPERATURE SENSOR

MASS AIRFLOW SENSOR

IGNITION SYSTEM

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ENGINE ELECTRICAL

16-37

SPECIAL TOOLS

M1163000600073

ON-VEHICLE SERVICE

KNOCK CONTROL SYSTEM CHECK

M1163001800081

Check the knock sensor circuit if diagnostic trouble code, No.
P0325 is shown.

<2.4L ENGINE>

Refer to GROUP 13A, Multiport Fuel Injection (MFI) <2.4L
Engine>

− Multiport Fuel Injection (MFI) Diagnosis − Diagnostic

Trouble Code Procedures

− DTC P0325 : Knock Sensor Circuit

P.13A-540

.

<3.8L ENGINE>

Refer to GROUP 13B, Multiport Fuel Injection (MFI) <3.8L
Engine>

− Multiport Fuel Injection (MFI) Diagnosis − Diagnostic

Trouble Code Procedures

− DTC P0325 : Knock Sensor Circuit

P.13B-596

.

AK400831AB

MASS AIRFLOW
SENSOR

PCM

IGNITION
SWITCH

IGNITION
COIL

SPARK PLUG

CYLINDER NO.

BATTERY

1

2

3

4

5

6

INTAKE AIR
TEMPERATURE SENSOR

ENGINE COOLANT
TEMPERATURE SENSOR

CAMSHAFT POSITION
SENSOR

CRANKSHAFT POSITION
SENSOR

TRANSMISSION RANGE

SWTCH

IGNITION SWITCH-ST

KNOCK SENSOR

TOOL

TOOL NUMBER AND
NAME

SUPERSESSION

APPLICATION

MD998773
Knock sensor wrench

MD998773-01

Knock sensor removal
and installation

IGNITION SYSTEM

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ENGINE ELECTRICAL

16-38

IGNITION COIL CHECK

M1163001200380

Check by the following procedure, and replace the coil if there
is a malfunction.

.

PRIMARY COIL AND IGNITION POWER
TRANSISTOR CONTINUITY CHECK

NOTE: An analog-type ohmmeter should be used.
NOTE: Connect the negative probe of the ohmmeter to termi-
nal 1.

CAUTION

This test must be performed quickly (in less than 10 sec-
onds) to prevent coil from burning and ignition power tran-
sistor from breaking.
1. Connect and disconnect 4.5

− 9.0 V battery between

terminal No. 2 and No. 3, and observe the ohmmeter
whether there is continuity or not.

2. If results do not agree with the table below, replace the

primary coil and ignition power transistor assembly.

.

SECONDARY COIL CHECK

NOTE: It is impossible to check the secondary coil through the
continuity check as a diode is integrated in the secondary coil
circuit of this ignition coil. Accordingly, check the secondary coil
in the following procedure.
1. Disconnect the ignition coil connector.
2. Remove the ignition coil and install a new spark plug to the

ignition coil.

3. Connect the ignition coil connector.
4. Ground the side electrode of the spark plug and crank the

engine.

5. Check that spark is produced between the electrodes of the

spark plug.

AK303638 AB

4.5 – 9.0 V

1 2 3

+

–

4.5

− 9.0 V POWER SUPPLY

BETWEEN 2

− 3

CONTINUITY BETWEEN
1

− 2

Current flowing

Yes

Current not flowing

No

IGNITION SYSTEM

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ENGINE ELECTRICAL

16-39

6. If no spark plug is produced, replace the ignition coil with a

new one and recheck.

7. If spark is produced with the new ignition coil, replace the

old one as it is faulty. If no spark is produced again, the
ignition circuit is suspected as faulty. Check the ignition
circuit.

SPARK PLUG TEST

M1163001500143

1. Remove the spark plug and connect to the ignition coil.

2. Ground the spark plug outer electrode (body), and crank the

engine.
Check that there is an electrical discharge between the
electrodes at this time.

SPARK PLUG CHECK AND CLEANING

M1163004300397

CAUTION

• Do not attempt to adjust the gap of the iridium plug.
• Cleaning of the iridium plug may result in damage to

the iridium tips. Therefore, if carbon deposits must be
removed, use a plug cleaner and complete cleaning
within 20 seconds to protect the electrode. Do not use a
wire brush.

Check the plug gap and replace if the limit is exceeded.

Standard value: 0.7

− 0.8 mm (0.028 − 0.031 inch)

Limit: 1.2 mm (0.047 inch)

CAMSHAFT POSITION SENSOR CHECK

M1163004400208

<2.4L ENGINE>

Refer to GROUP 13A, Multiport Fuel Injection (MFI) <2.4L
Engine>

− Multiport Fuel Injection (MFI) Diagnosis − Diagnostic

Trouble Code Procedures

− DTC P0340 : Camshaft Position

Sensor Circuit

P.13A-566

.

AKX00432

SPARK PLUG

AB

AKX00277

DEFECTIVE INSULATION

DEFECTIVE INSULATION

DEFECTIVE
INSULATION

GOOD

AB

AKX00383

AKX00383

IRIDIUM TIP

AK