Mitsubishi Lancer Evolution 8. Manual — part 176
MPI – TROUBLESHOOTING
13A-90
Item
No.
Check Items
Checking Conditions (engine condition)
Normal condition
•
External air
temperature sensor
ambient temp.: 18ºC
•
A/C set temp.:
Minimum temperature
•
A/C air flow:
Maximum (Max Cool)
1V or less
85
A/C load
•
Engine:
idling
•
A/C switch:
ON (A/C
compressor
operating)
•
A/C set temp.:
Cabin temperature
•
A/C air flow:
Minimum
Battery voltage
•
Ignition switch: ON
•
Intercooler water spray switch: ON
1V or less
66
Intercooler
water spray
switch (Auto)
•
Ignition switch: ON
•
Intercooler water spray switch: OFF
Battery voltage
•
Ignition switch: ON
•
Intercooler water spray switch: ON
1V or less
67
Intercooler
water spray
switch
(Manual)
•
Ignition switch: ON
•
Intercooler water spray switch: OFF
Battery voltage
68
Ignition switch
– ST
Engine: cranking
8V or more
99
Ignition switch
– IG
Ignition switch: ON
Battery voltage
71
O
2
sensor
Engine: after warming up, maintain 2,500 rpm
(Check using a digital voltmeter)
0
↔
8V (changes repeatedly)
Throttle valve set to
idle position
0.535 to 0.735V
78
Throttle
position sensor
Ignition switch: ON
Throttle valve set to
fully open
4.5 to 5.0V
80Vehicle speed
sensor
•
Ignition switch: ON
•
Vehicle moving slowly forwards
0
↔
5V
(changes repeatedly)
A/C switch: OFF
0.5V or less
83
A/C switch
Engine: idling
•
A/C switch: ON
•
A/C set temp.
When cabin temp.
25ºC or more: Max
cool
When cabin temp.
25ºC or less: Max
Hot
Battery voltage
Ignition switch: ON
Battery voltage
40Intercooler
water spray
light
Ignition switch: LOCK (OFF)
1V or less
MPI – TROUBLESHOOTING
13A-91
8-2. TABLE SHOWING HARNESS SIDE CONNECTOR TERMINAL RESISTANCES AND CONTINUITY
Engine ECU harness side connectors
Terminal number
Check item
Standard value, normal condition (Check
condition)
1-47
No.1 injector
9-47
No.2 injector
24-47
No.3 injector
2-47
No.4 injector
7.8 to 9.2
Ω
(at 20ºC)
3-47
O
2
sensor
11to18
Ω
(at 20ºC)
5-47
Secondary air control solenoid valve
28 to 36
Ω
(at 20ºC)
14-47
Stepper motor coil (A1)
28-47
Stepper motor coil (A2)
15-47
Stepper motor coil (B1)
29-47
Stepper motor coil (B2)
28 to 33
Ω
(at 20ºC)
16-47
Purge control solenoid valve
22 to 26
Ω
(at 20ºC)
41-47
Waste gate solenoid valve
62 to 74
Ω
(at 20ºC)
14 to 17k
Ω
(at 20ºC)
5.1 to 6.5k
Ω
(at 0ºC)
2.1 to 2.7k
Ω
(at 20ºC)
0.9 to 1.3k
Ω
(at 40ºC)
0.48 to 0.68k
Ω
(at 60ºC)
44-49
Water temperature sensor
0.26 to 0.36k
Ω
(at 80ºC)
46-Body earth
58-Body earth
Engine ECU earth
There is continuity (0
Ω
)
47-48
Fuel pressure control solenoid valve
28 to 36
Ω
(at 20ºC)
13 to 17
Ω
(when intake air temp. -20ºC)
5.3 to 6.7
Ω
(when intake air temp. 0ºC)
2.3 to 3.0
Ω
(when intake air temp. 20ºC)
1.0 to 1.5
Ω
(when intake air temp. 40ºC)
0.56 to 0.76
Ω
(when intake air temp. 60ºC)
62-49
Intake air temperature sensor
0.30 to 0.42
Ω
(when intake air temp. 80ºC)
MPI – TROUBLESHOOTING
13A-92
9-1 Air flow sensor
<Measurement Method>
(1) Disconnect the air flow sensor connector, and connect the special tool
(test harness MB991709). (All the terminals should be connected)
(2) Connect the oscilloscope to air flow sensor connector terminal No.3.
Comments
When taking measurements at the engine ECU connector, connect
oscilloscope probe to terminal No.61.
<Standard waveform>
Observation conditions
9. Checks using an oscilloscope
Taking waveform measurements using an oscilloscope means that sensor
outputs signals and actuator drive signals can be checked visually.
Observation conditions (Only change to the conditions already specified is engine speed, which is as follows)
Standard waveform
Oscilloscope
Standard waveform
Time T shortens as intake
air volume increases
Probe switch
x1
AC-GND-DC
DC
TIME/DIV.
5ms
VOLTS/DIV.
2V
Other
-
Engine
Idling
Engine speed
2,000rpm
MPI – TROUBLESHOOTING
13A-93
<An explanation of waveforms>
• The air flow sensor sends a frequency pulse signal relative in size to the air flow to the engine ECU. By measuring the pulse
signal cycle time T (seconds), the output signal frequency can be calculated using the following formula:
Frequency (Hz) = 1/T (seconds)
<Waveform Observation Points>
• Check that, as the engine speed increases, cycle time T gets shorter, and frequency increases.
<Examples of abnormal waveforms>
• Example 1
Waveform characteristics
Rectangular waveform is output, even when the engine is not started.
Cause of problem
Sensor interface fault
• Example 2
Waveform characteristics
Unstable waveform with unstable frequency.
However, when an ignition leak occurs during acceleration, the
waveform will momentarily be distorted, even though the air flow sensor
is normal.
Cause of problem
Damaged rectifier or vortex generation column
9-2 Cam position sensor and crank angle sensor
<Measurement method>
(1) Undo the camshaft position sensor connector, then connect the
special test harness (MB991709). (All terminals should be
connected)
(2) Undo crank angle sensor connector, then connect the special test
harness (MD998478).
(3) Connect the probe for each channel on the oscilloscope to the
camshaft position sensor connector No.2 terminal, and to the crank
angle sensor connector terminal No.2 (the black clip on the special
tool).
Note
When doing engine ECU connector measurement, connect the
probe for each channel on the oscilloscope to terminal No.50
(camshaft position sensor) and terminal No.43 (crank angle sensor).
Camshaft
position sensor
connector
Oscilloscope
Crank
angle
sensor
connector
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