Mitsubishi Pajero Pinin. Manual - part 126

 

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Mitsubishi Pajero Pinin. Manual - part 126

 

 

MPI <4G9> – 

Troubleshooting

13C-90

Examples of Abnormal Wave Patterns

D

Example 1

Cause of problem

Sensor interface malfunction

Wave pattern characteristics

Rectangular wave pattern is output even when the engine
is not started.

D

Example 2

Cause of problem

Loose timing belt
Abnormality in sensor disk

Wave pattern characteristics

Wave pattern is displaced to the left or right.

INJECTOR

Measurement Method

1.

Disconnect the injector connector, and then connect the
special tool (test harness: MB991348) in between.
(Both the power supply side and engine-ECU side should
be connected.)

2.

Connect the analyzer special patterns pickup to terminal
2 of the injector connector.

Alternate Method (Test harness not available)

1.

Connect the analyzer special patterns pickup to
engine-ECU terminal 1.  (When checking the No. 1
cylinder.)

2.

Connect the analyzer special patterns pickup to
engine-ECU terminal 14.  (When checking the No. 2
cylinder.)

3.

Connect the analyzer special patterns pickup to
engine-ECU terminal 2.  (When checking the No. 3
cylinder.)

4.

Connect the analyzer special patterns pickup to
engine-ECU terminal 15.  (When checking the No. 4
cylinder.)

Analyzer

MPI <4G9> – 

Troubleshooting

13C-91

Standard Wave Pattern

Observation conditions

Function

Special patterns

Pattern height

Variable

Variable knob

Adjust while viewing the wave pattern

Pattern selector

Display

Engine r/min

Idle speed

Standard wave pattern

(V)

Point A

Point B

Solenoid back electromotive force
(Approx. 7

×

10 V)

Injector drive time

Power voltage

Drive signal: ON

Drive signal: OFF

Time

50

0

Wave Pattern Observation Points

Point A: Height of solenoid back electromotive force

Contrast with standard wave pattern

Probable cause

Solenoid coil back electromotive force is low or doesn’t
appear at all.

Short in the injector solenoid

Point B: Injector drive time

D

The injector drive time will be synchronized with the MUT-

II

tester display.

D

When the engine is suddenly raced, the drive time will
be greatly extended at first, but the drive time will soon
match the engine speed.

When idling
When racing

---
––

MPI <4G9> – 

Troubleshooting

13C-92

IDLE SPEED CONTROL (ISC) SERVO (STEPPER
MOTOR)

Measurement Method

1.

Disconnect the ISC servo connector, and connect the
special tool (test harness: MB991709) in between.

2.

Connect the analyzer special patterns pickup to the ISC
servo-side connector terminal 1, terminal 3, terminal 4
and terminal 6 respectively.

Alternate Method (Test harness not available)

1.

Connect the analyzer special patterns pickup to
engine-ECU terminal 4, connection terminal 5, connection
terminal 17, and connection terminal 18 respectively.

Standard Wave Pattern

Observation conditions

Function

Special patterns

Pattern height

High

Pattern selector

Display

Engine condition

When the engine coolant temperature is 20

_

C or below, turn the ignition switch from LOCK

(OFF) position to ON (without starting the engine).

While the engine is idling, turn the A/C switch to ON.

Immediately after starting the warm engine

Standard wave pattern

Stepper
motor
control
signal
wave
pattern

(V)

30

20

10

The wave pattern
appears for an
instant, but soon
disappears.

Point B
Coil reverse electromotive
force (Approx. 3 

×

 10V)

Point A
Induced electromotive force
from the motor turning

Time

Special
patterns
pickup

Analyzer

MPI <4G9> – 

Troubleshooting

13C-93

Wave Pattern Observation Points

Check that the standard wave pattern appears when the stepper motor is operating.
Point  A:

Presence or absence of induced electromotive force from the motor turning. (Refer to the abnormal

wave pattern.)

Contrast with standard wave pattern

Probable cause

Induced electromotive force does not appear or is extremely small.

Motor is malfunctioning

Point B:

Height of coil reverse electromotive force

Contrast with standard wave pattern

Probable cause

Coil reverse electromotive force does not appear or is extremely small.

Short in the coil

Examples of Abnormal Wave Pattern

D

Example 1

Cause of problem

Motor is malfunctioning. (Motor is not operating.)

Wave pattern characteristics

Induced electromotive force from the motor turning does
not appear.

D

Example 2

Cause of problem

Open circuit in the line between the stepper motor and
the engine-ECU.

Wave pattern characteristics

Current is not supplied to the motor coil on the open circuit
side. (Voltage does not drop to 0 V.)
Furthermore, the induced electromotive force waveform
at the normal side is slightly different from the normal
waveform.

Open
circuit
side

Nor-
mal
side

 

 

 

 

 

 

 

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