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