Mitsubishi Pajero Pinin. Manual — part 125
MPI <4G9> –
Troubleshooting
13C-86
Terminal
No.
Normal condition (Check condition)
Inspection item
72 – 92
Intake air temperature sensor
5.3 – 6.7 k
Ω
(When intake air temperature is 0
_
C)
2.3 – 3.0 k
Ω
(When intake air temperature is 20
_
C)
1.0 – 1.5 k
Ω
(When intake air temperature is 40
_
C)
0.30 – 0.42 k
Ω
(When intake air temperature is 80
_
C)
83 – 92
Engine coolant temperature sensor
5.1 – 6.5 k
Ω
(When coolant temperature is 0
_
C)
2.1 – 2.7 k
Ω
(When coolant temperature is 20
_
C)
0.9 – 1.3 k
Ω
(When coolant temperature is 40
_
C)
0.26 – 0.36 k
Ω
(When coolant temperature is 80
_
C)
MPI <4G9> –
Troubleshooting
13C-87
INSPECTION PROCEDURE USING AN ANALYZER
AIR FLOW SENSOR (AFS)
Measurement Method
1.
Disconnect the air flow sensor connector, and connect
the special tool (test harness: MB991709) in between.
(All terminals should be connected.)
2.
Connect the analyzer special patterns pickup to air flow
sensor connector terminal 3.
Alternate Method (Test harness not available)
1.
Connect the analyzer special patterns pickup to
engine-ECU terminal 90.
Standard Wave Pattern
Observation conditions
Function
Special patterns
Pattern height
Low
Pattern selector
Display
Engine r/min
Idle speed
Standard wave pattern
(V)
10
0
The time (cycle time) T is reduced when
the amount of intake air increases.
Times T1 and T2 are equal.
Time
T
T1
T2
Observation conditions (from conditions above engine speed is increased by racing.)
Time
(V)
10
0
T
Wave Pattern Observation Points
Check that cycle time T becomes shorter and the frequency increases when the engine speed is increased.
Analyzer
Special
patterns
pickup
MPI <4G9> –
Troubleshooting
13C-88
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
Damaged rectifier or vortex generation column
Wave pattern characteristics
Unstable wave pattern with non-uniform frequency.
However, when an ignition leak occurs during acceleration,
the wave pattern will be distorted temporarily, even if the
air flow sensor is normal.
CAMSHAFT POSITION SENSOR AND CRANK ANGLE
SENSOR
Measurement Method
1.
Disconnect the camshaft position sensor connector and
connect the special tool (test harness: MB991659) and
jumper wire in between. (All terminals should be
connected.)
2.
Connect the analyzer special patterns pickup to camshaft
position sensor terminal 2.
3.
Disconnect the crank angle sensor connector and connect
the special tool (test harness: MB991658) in between.
4.
Connect the analyzer special patterns pickup to crank
angle sensor terminal 3.
Alternate Method (Test harness not available)
1.
Connect the analyzer special patterns pickup to
engine-ECU terminal 88. (When checking the camshaft
position sensor signal wave pattern.)
2.
Connect the analyzer special patterns pickup to
engine-ECU terminal 89. (When checking the crank angle
sensor signal wave pattern.)
Standard Wave Pattern
Observation conditions
Function
Special patterns
Pattern height
Low
Pattern selector
Display
Engine r/min
Idle speed
Crank angle sensor connector
Camshaft position sensor connec-
tor
Analyzer
Special patterns
pick-up
MPI <4G9> –
Troubleshooting
13C-89
Standard wave pattern
Crank angle
sensor output
wave pattern
(V)
75
_
BTDC
2 engine revolutions
(1 camshaft revolution)
5
_
BTDC
The time (cycle time) T is
reduced when the engine
speed increases
0
Camshaft posi-
tion sensor out-
put wave pat-
tern
TDC: Top dead centre
131
°
49
°
No. 1 TDC
No. 3 TDC
No. 4 TDC
No. 2 TDC
Time
0
56
°
34
°
Wave Pattern Observation Points
Check that cycle time T becomes shorter when the engine speed increases.
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.
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