Mitsubishi Grandis. Manual — part 650

IGNITION SYSTEM

ENGINE ELECTRICAL

16-24

4. Check the insulation between commutator

segments and armature coils. The armature coils
are properly insulated if no continuity is present.

5. Check continuity between a segment and another.

There is no open circuit in the tested coil if there is
continuity.

MAGNETIC SWITCH

1. Coil open circuit test

• Check that there is continuity between the M

terminal and body A.

• If there is no continuity, replace the magnetic

switch.

2. Contact fusion check

• Check that there is no continuity between the B

terminal and M terminal.

• If there is continuity, replace the magnetic switch.

3. Switch contact check

• Push the indicated end of the magnetic switch

with a strong force to close the internal contacts.
Without releasing the switch end, check that
there is continuity between the B terminal and M
terminal.

• If there is no continuity, replace the magnetic

switch.

IGNITION SYSTEM

GENERAL INFORMATION

M1163000100380

This system is equipped with four ignition coils with
built-in power transistors for each of the cylinders.

Interruption of the primary current flowing in the
primary side of an ignition coil generates a high
voltage in the secondary side of ignition coil. The
high voltage thus generated is applied to the spark
plugs to generate sparks. The engine-ECU <M/T> or

AK304693

AK304694

AK202891

A

M terminal

AB

AK202892

M terminal

B terminal

AB

AK202893

M terminal

B terminal

AB

IGNITION SYSTEM

ENGINE ELECTRICAL

16-25

engine-A/T-ECU <A/T> turns the power transistors
inside the ignition coils 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 1-3-4-2.
The engine-ECU <M/T> or engine-A/T-ECU <A/T>
determines which ignition coil should be controlled
by means of the signals from the camshaft position
sensor and the crank angle sensor. It also detects
the crankshaft position, in order to provide ignition at
the most appropriate timing in response to the
engine operation conditions.

When the engine is cold or running at high altitudes,
the ignition timing is slightly advanced to provide
optimum performance. Furthermore, if knocking
occurs, the ignition timing is gradually retarded until
knocking ceases.

SYSTEM DIAGRAM

IGNITION COIL SPECIFICATION

SPARK PLUG SPECIFICATIONS

AK303631

Air flow sensor

Intake air temperature sensor

Engine coolant temperature
sensor

Accelerator pedal position
sensor

Camshaft position sensor

Crank angle sensor

Barometric pressure sensor

Detonation sensor

Vehicle speed sensor <M/T>

Inhibitor switch <A/T>

Ignition switch-ST

Engine-ECU
<M/T> or
Engine-A/T-
ECU <A/T>

Ignition coil

Cylinder No.

1

2

3

AC

4

Spark plug

Ignition
switch

Battery

Item

Specification

Type

Molded 4-coil

Item

Specification

NGK

LZFR6AI

IGNITION SYSTEM

ENGINE ELECTRICAL

16-26

SERVICE SPECIFICATIONS

M1163000300232

SPARK PLUG

SPECIAL TOOL

M1163000600200

ON-VEHICLE SERVICE

IGNITION COIL (WITH BUILT-IN POWER TRANSISTOR) CHECK

M1163001200432

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

PRIMARY COIL AND POWER
TRANSISTOR CONTINUITY CHECK

NOTE:

.

•

An analogue-type circuit tester should be used.

•

Connect the negative (-) prove of the circuit tester
to terminal No. 1.

CAUTION

This test must be performed quickly (in less

than 10 seconds) to prevent coil from burning
and power transistor from breakage.
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.

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. Earth the side electrode of the spark plug and

crank the engine.

5. Check that spark is produced between the

electrodes of the spark plug.

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 CHECK AND CLEANING

M1163004300449

1. Remove the spark plugs.

Item

Standard value

Limit

Spark plug gap mm

0.7

− 0.8

1.2

Tool

Number

Name

Use

MD998773

Detonation sensor
wrench

Detonation sensor
removal and installation

AK202356

1 2 3

AG

4.5 – 9.0 V

–

+

–

+

4.5

− 9.0 V power

supply between 2

− 3

Continuity between 1

−

2

When current is flowing

Continuity

When current is not
flowing

No continuity

IGNITION SYSTEM

ENGINE ELECTRICAL

16-27

CAUTION

• Do not attempt to adjust the gap of the iridium

plug.

• Always use a plug cleaner and finish cleaning

within 20 seconds. Do not use wire brushes.
Otherwise, the iridium tip may be damaged.

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

exceeded.
Standard value: 0.7

− 0.8 mm

Limit: 1.2 mm

CAUTION

Be careful not to allow foreign matter in
cylinders.
3. Clean the engine plug holes.
4. Install the spark plugs.

CAMSHAFT POSITION SENSOR CHECK

M1163004400316

Check the camshaft position sensor circuit if
self-diagnosis code, No. P0340 is shown.

(Refer to

P.13A-167

, GROUP 13A

− Troubleshooting

− Inspection Procedure for Diagnosis Code.)

CRANK ANGLE SENSOR CHECK

M1163004500379

Check the crank angle sensor circuit if self-diagnosis
code, No. P0335 is shown.

(Refer to

P.13A-157

, GROUP 13A

− Troubleshooting

− Inspection Procedure for Diagnosis Code.)

DETONATION SENSOR CHECK

M1163002900081

Check the detonation sensor circuit if self-diagnosis
code, No. P0325 is shown.
(Refer to

P.13A-154

, GROUP 13A

− Troubleshooting

− Inspection Procedure for Diagnosis Code.)

IGNITION COIL

REMOVAL AND INSTALLATION

M1163004000545

AKX00383

Iridium tip

AN

Pre-removal and Post-installation Operation
Engine Cover Removal and Installation (Refer to GROUP
11A, Camshaft and Valve Stem Seal

P.11A-16

).

AC313043

1

2

3

10 ± 2 N·m

AB

25 ± 5 N·m