Mitsubishi 380. Manual — part 252

IGNITION SYSTEM

ENGINE ELECTRICAL

16-30

IGNITION SYSTEM

GENERAL DESCRIPTION

M1163000100528

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 engine control unit (ECU) controls the three
ignition power transistors to turn them alternately ON
and OFF. This causes the primary currents 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 ECU 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.

SPECIAL TOOLS

M1163000600073

06DB024A

IGNITION

SWITCH

BATTERY

TOOL

TOOL NUMBER AND
NAME

SUPERSESSION

APPLICATION

MD998773
Knock sensor wrench

MD998773-01

Knock sensor removal
and installation

IGNITION SYSTEM

ENGINE ELECTRICAL

16-31

ON-VEHICLE SERVICE

KNOCK CONTROL SYSTEM CHECK

M1163001800081

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

Refer to GROUP 13B, Multiport Fuel Injection (MPI)

− Multiport

Fuel Injection (MPI) Diagnosis

− Diagnostic Trouble Code Pro-

cedures

− DTC P0325 : Knock Sensor Circuit

13A-346

.

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: No test can be performed on the Primary side of coil.

.

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. Disable vehicle fuel pump by removing fuel pump relay or

disconnecting fuel pump connector D-18 (under rear seat).

5. Ground the side electrode of the spark plug and crank the

engine.

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

spark plug.

7. If no spark is produced, replace the ignition coil with a new

one and recheck.

8. 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.

IGNITION SYSTEM

ENGINE ELECTRICAL

16-32

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

Refer to GROUP 13B, Multiport Fuel Injection (MPI)

− Multiport

Fuel Injection (MPI) Diagnosis

− Diagnostic Trouble Code Pro-

cedures

− DTC P0340 : Camshaft Position Sensor Circuit

13A-372

.

CRANKSHAFT POSITION SENSOR CHECK

M1163004500261

Refer to GROUP 13B, Multiport Fuel Injection (MPI)

− Multiport

Fuel Injection (MPI) Diagnosis

− Diagnostic Trouble Code Pro-

cedures

− DTC P0335 : Crankshaft Position Sensor Circuit

13A-354

.

AKX00432

SPARK PLUG

AB

AKX00277

DEFECTIVE INSULATION

DEFECTIVE INSULATION

DEFECTIVE
INSULATION

GOOD

AB

AKX00383

AKX00383

IRIDIUM TIP

AK

IGNITION SYSTEM

ENGINE ELECTRICAL

16-33

IGNITION COIL

REMOVAL AND INSTALLATION

M1163004000448

AC306928

10 ± 2 N·m
89 ± 17 in-lb

25 ± 4 N·m
18 ± 3 ft-lb

25 ± 4 N·m
18 ± 3 ft-lb

10 ± 2 N·m
89 ± 17 in-lb

1

2

3

4

5

6

AB

REMOVAL STEPS

•

ENGINE COVER (REFER TO
GROUP 11C, ENGINE ASSEMBLY

11A-14

).

1.

IGNITION COIL CONNECTORS
(LH)

2.

IGNITION COILS (LH)

3.

SPARK PLUGS (LH)

•

INTAKE MANIFOLD PLENUM
(REFER TO GROUP 15, INTAKE
MANIFOLD PLENUM

P.15-5

).

4.

IGNITION COIL CONNECTORS
(RH)

5.

IGNITION COILS (RH)

6.

SPARK PLUGS (RH)

REMOVAL STEPS (Continued)