fuel MITSUBISHI LANCER EVOLUTION VI 1999 Owner's Guide

MPI – Troubleshooting13-42
INSPECTION PROCEDURE 31
Oxygen sensor system
Probable cause
When CO or HC concentration is too high, the malfunction of the parts shown at
right may be the cause.

The oxygen sensor detects the density of oxygen in exhaust gas and inputs it
to the engine-ECU after converting into a voltage signal.

The engine-ECU controls the fuel injection amount based on this signal such that
the stoichiometric air/fuel mixture ratio can be obtained.
Malfunction of oxygen sensor

Improper connector contact, open or short-circuited
harness wire

Malfunction of engine-ECU
OK
Replace the engine-ECU.
Check the harness wire between
engine-ECU and oxygen sensor connector.NG
Repair
NG
OK
Check trouble symptom.
OK
Replace the engine-ECU.
NG
Check the harness wire between
engine-ECU and oxygen sensor connector.NG
Repair
OK
Check trouble symptom.
OK
Check the following connector: A-63NG
Repair
OK
Measure at the oxygen sensor connector A-63.

Disconnect the connector, and measure at the harness side.

Continuity between 2 and earth
OK:ContinuityNGCheck the following connector: B-62NG
Repair
Check the oxygen sensor. (Refer to P.13-32.)*NG
Replace
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-43
INSPECTION PROCEDURE 31
Oxygen sensor system
Probable cause
When CO or HC concentration is too high, the malfunction of the parts shown at
right may be the cause.

The oxygen sensor detects the density of oxygen in exhaust gas and inputs it
to the engine-ECU after converting into a voltage signal.

The engine-ECU controls the fuel injection amount based on this signal such that
the stoichiometric air/fuel mixture ratio can be obtained.
Malfunction of oxygen sensor

Improper connector contact, open or short-circuited
harness wire

Malfunction of engine-ECU
OK
Replace the engine-ECU.
NG
Check the harness wire between oxygen sensor, engine-ECU,
and repair if necessary.
OK
Check trouble symptom.
NG
Check the harness wire between oxygen sensor and engine-ECU,
and repair if necessary.
OK
Check trouble symptom.
OK
Check trouble symptom.NGCheck the harness wire between
engine-ECU and oxygen sensor.NG
Repair
OK
Check the following connector: B-61NG
Repair
OK
NG
Measure at the engine-ECU connector B-61.

Disconnect the connector, and measure at the harness side.

Voltage between 60 and earth
(Ignition switch: ON)
OK:System voltageCheck the following connector: A-63NG
Repair 1. NG
Check the harness wire between oxygen sensor and control relay,
and repair if necessary.
OK
2. NG
Measure at the oxygen sensor connector A-63.

Disconnect the connector, and measure at the harness side.
1. Voltage between 1 and earth
(Ignition switch: ON)
OK:System voltage
2. Continuity between 2 and earth
OK:Continuity
Check the following connector: B-62NG
Repair
Check the oxygen sensor. (Refer to P.13-32)*NG
Replace
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-45
INSPECTION PROCEDURE 34
Fuel pressure control valve system
Probable cause
The fuel pressure control valve switches the pressure introduction into the fuel pressure
regulator between the intake manifold and atmosphere.
Malfunction of solenoid valve

Improper connector contact, open or short-circuited
harness wire

Malfunction of engine-ECU
NGReplace the engine-ECU.
OK
Check trouble symptom.
NG
Check the harness wire between engine-ECU and solenoid valve
connector, and repair if necessary.
OK
Check trouble symptom.
OK
Check the following connector: B-59NG
Repair
OK
Measure at the engine-ECU connector B-59.

Disconnect the connector, and measure at the harness side.

Voltage between 3 and earth
(Ignition switch: ON)
OK:System voltageNGCheck the following connector: A-12NG
Repair NG
Check the harness wire between control relay and solenoid valve
connector, and repair if necessary.
OK
Measure at the fuel pressure control valve connector A-12.

Disconnect the connector, and measure at the harness side.

Voltage between 1 and earth
(Ignition switch: ON)
OK:System voltage
Check the fuel pressure control valve.NG
Replace
INSPECTION PROCEDURE 35
Waste gate solenoid valve
Probable cause
The waste gate solenoid valve controls the boost pressure introduced into the waste
gate actuator in the turbocharger.
Malfunction of solenoid valve

Improper connector contact, open or short-circuited
harness wire

Malfunction of engine-ECU
NGReplace the engine-ECU.
OK
Check trouble symptom.
NG
Check the harness wire between engine-ECU and solenoid valve
connector, and repair if necessary.
OK
Check trouble symptom.
OK
Check the following connector: B-59NG
Repair
OK
Measure at the engine-ECU connector B-59.

Disconnect the connector, and measure at the harness side.

Voltage between 11 and earth
(Ignition switch: ON)
OK:System voltageNGCheck the following connector: A-23NG
Repair NG
Check the harness wire between control relay and solenoid valve
connector, and repair if necessary.
OK
Measure at the waste gate solenoid valve connector A-23.

Disconnect the connector, and measure at the harness side.

Voltage between 2 and earth
(Ignition switch: ON)
OK:System voltage
Check the waste gate solenoid valve.
(Refer to Group 15 – On-vehicle service.)*NG
Replace
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-47
INSPECTION PROCEDURE 37
MUT-II: Inspection of no initial combustion
MUT-II Data list
16 engine-ECU power supply voltage (Refer to P.13-57.)NGCheck the power supply and ignition switch-IG system.
(Refer to P.13-35, INSPECTION PROCEDURE 24.)
OK
Does the camshaft rotate at the engine cranking?
(When oil filler cap is removed.)NoCheck timing belt for breakage.
Ye s
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
No
MUT-II Data list
22 Crank angle sensor
OK:Cranking speed is displayed.NGCheck the crank angle sensor system.
(Refer to P.13-11, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 22.)
OK
MUT-II Actuator test
07 Fuel pump (Refer to P.13-61.)NGCheck the fuel pump system.
(Refer to P.13-36, INSPECTION PROCEDURE 25.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13-10, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
INSPECTION PROCEDURE 38
Ignition system: Inspection of no initial combustion.
OK
Check the ignition timing when cranking.
OK:Approx. 5BTDCNGCheck that the crank angle sensor and the timing belt cover are
installed properly.
NGCheck the ignition circuit system.
(Refer to P.13-44, INSPECTION PROCEDURE 32.)Check by connecting a timing light to the spark plug cable.
OK:Timing light flashes during cranking.

MPI – Troubleshooting13-48
INSPECTION PROCEDURE 39
MUT-II: Check if uncomplete combustion occurs.
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
No
MUT-II Actuator test
07 Fuel pump (Refer to P.13-61.)NGCheck the fuel pump system.
(Refer to P.13-36, INSPECTION PROCEDURE 25.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13-10, INSPECTION PROCEDURES FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Data list
18 Ignition switch-ST (Refer to P.13-57.)NGCheck the ignition switch-ST system.
(Refer to P.13-38, INSPECTION PROCEDURE 27.)
INSPECTION PROCEDURE 40
Check if hunting occurs.
Clean the throttle body.
Check and adjust the fixed SAS. (Refer to P.13-30.)*
Check trouble symptom.
NG
Inspect the intake of air into the air intake system

Broken intake manifold gasket

Broken air intake hose

Broken vacuum hose

Positive crankcase ventilation valve does not operate.
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-49
INSPECTION PROCEDURE 41
MUT-II: Check if idling speed is unstable.
OK
MUT-II Data list
45 ISC servo position (Refer to P.13-60.)NGAdjust the basic idle speed. (Refer to P.13-30.)*
MUT-II Data list
28 A/C switch (Refer to P.13-58.)NGCheck the A/C switch and A/C relay system.
(Refer to P.13-39. INSPECTION PROCEDURE 29.)
OK
OK
MUT-II Data list
27 Power steering fluid pressure switch (Refer to P.13-58)NGCheck the power steering fluid pressure switch system.
(Refer to P.13-39, INSPECTION PROCEDURE 28.)
1. Inspect the intake of air into the air intake system.

Broken intake manifold gasket

Broken vacuum hose

PCV valve does not operate.

Broken air intake hose
2. Check the injector for clog.
OK
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 0–400 mV and 600–1,000 mV during
idlingNGCheck the fuel pressure. (Refer to P.13-30.)*
OK
MUT-II Data list
11 Oxygen sensor
OK:600–1,000 mV during sudden racingNGCheck the oxygen sensor system. (Refer to P.13-42, INSPECTION
PROCEDURE 31.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13-21.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13-10, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13-58.)NGCheck the barometric pressure sensor system. (Refer to P.13-14,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13-56.)NGCheck the intake air temperature sensor system. (Refer to P.13-9,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
MUT-II Data list
26 Idle position switch (Refer to P.13-58.)NGCheck the idle position switch system.
(Refer to P.13-38, INSPECTION PROCEDURE 26.)
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-50
INSPECTION PROCEDURE 42
MUT-II: Engine stalling inspection when the engine is warmed up and idling.
OK
MUT-II Data list
26 Idle position switch (Refer to P.13-58.)NGCheck the idle position switch system.
(Refer to P.13-38, INSPECTION PROCEDURE 26.)
OK
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13-56.)NGCheck the intake air temperature sensor system. (Refer to P.13-9,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13-58.)NGCheck the barometric pressure sensor system. (Refer to P.13-14,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13-10, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Data list
11 Oxygen sensor
OK:600–1,000 mV during sudden racingNGCheck the oxygen sensor system. (Refer to P.13-42, INSPECTION
PROCEDURE 31.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 0–400 mV and 600–1,000 mV during
idlingNGCheck the fuel pressure. (Refer to P.13-30.)*
OK
MUT-II Data list
27 Power steering fluid pressure switch (Refer to P.13-58.)NGCheck the power steering fluid pressure switch system.
(Refer to P.13-39, INSPECTION PROCEDURE 28.)
OK
MUT-II Data list
28 A/C switch (Refer to P.13-58.)NGCheck the A/C switch and A/C relay system.
(Refer to P.13-39, INSPECTION PROCEDURE 29.)
OK
MUT-II Data list
45 ISC servo position (Refer to P.13-60.)NGAdjust the basic idle speed. (Refer to P.13-30.)*
1. Inspect the intake of air into the air intake system

Broken intake manifold gasket

Broken vacuum hose

PCV valve does not operate.

Broken air intake hose
2. Check the injector for clog.
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-51
INSPECTION PROCEDURE 43
MUT-II: Check if hesitation, sag, stumble or poor acceleration occurs.
OK
MUT-II Data list
26 Idle position switch (Refer to P.13-58.)NGCheck the idle position switch system.
(Refer to P.13-38, INSPECTION PROCEDURE 26.)
OK
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13-56.)NGCheck the intake air temperature sensor system. (Refer to P.13-9,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13-58.)NGCheck the barometric pressure sensor system. (Refer to P.13-14,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13-10, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Data list
14 Throttle position sensor (Refer to P.13-57.)NGCheck the throttle position sensor system. (Refer to P.13-9, IN-
SPECTION PROCEDURE FOR DIAGNOSIS CODE 14.)
OK
MUT-II Actuator test
12 Waste gate solenoid valve (Refer to P.13-61.)NGCheck the waste gate solenoid valve system.
(Refer to P.13-45, INSPECTION PROCEDURE 35.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 600–1,000 mV during sudden racingNGCheck the oxygen sensor system. (Refer to P.13-42, INSPECTION
PROCEDURE 31.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 0–400 mV and 600–1,000 mV during
idlingNGCheck the fuel pressure. (Refer to P.13-30.)*
OK
MUT-II Actuator test
09 Fuel pressure control valve (Refer to P.13-61.)NGCheck the fuel pressure control valve system.
(Refer to P.13-45, INSPECTION PROCEDURE 34.)
1. Inspect the intake of air into the air intake system

Broken intake manifold gasket

Broken vacuum hose

PCV valve does not operate.

Broken air intake hose
2. Check the injector for clog.
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-52
INSPECTION PROCEDURE 44
MUT-II: Check if surge occurs.
MUT-II Data list
26 Idle position switch (Refer to P.13-58.)NGCheck the idle position switch system.
(Refer to P.13-38, INSPECTION PROCEDURE 26.)
OK
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13-56.)NGCheck the intake air temperature sensor system. (Refer to P.13-9,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13-58.)NGCheck the barometric pressure sensor system. (Refer to P.13-14,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13-10, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Data list
14 Throttle position sensor (Refer to P.13-57.)NGCheck the throttle position sensor system. (Refer to P.13-9, IN-
SPECTION PROCEDURE FOR DIAGNOSIS CODE 14.)
OK
MUT-II Data list
11 Oxygen sensor
OK:600–1,000 mV during sudden racingNGCheck the oxygen sensor system.
(Refer to P.13-42, INSPECTION PROCEDURE 31.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 0–400 mV and 600–1,000 mV during
idlingNGCheck the fuel pressure. (Refer to P.13-30.)*
1. Inspect the intake of air into the air intake system

Broken intake manifold gasket

Broken vacuum hose

PCV valve does not operate.

Broken air intake hose
2. Check the injector for clog.OK
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-53
INSPECTION PROCEDURE 45
Check the engine-ECU power supply and earth circuit.
Measure at the engine-ECU connectors, B-59, B-60, B-62.

Disconnect the connector and measure at the harness side
1. Voltage between 82 and earth (Ignition switch: ON)
OK:System voltage
2. Voltage between 38 and earth
OK:System voltage
3. Voltage between 12, 25 and earth (Ignition switch: ON)
OK:System voltage (when the terminal 38 is earthed)
4. Continuity between 13, 26 and earth
OK:Continuity
5. Voltage between 80 and earth
OK:System voltage1. NGCheck the following
connectors: B-65, B-76NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between engine-ECU and
ignition switch connector.NG
Repair
OK
Check the ignition switch. (Refer to GROUP 54.)
2, 3. NG
4. NG
Check the harness wire between engine-ECU and earth, and repair
if necessary.
5. NG
OK
Check the following
connectors:
B-59, B-60, B-62NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
Check the following connectors:
B-65, B-49, B-75, B-73NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between engine-ECU and battery, and
repair if necessary.
Check the harness wire between engine-ECU and control relay
connector, and repair if necessary.
INSPECTION PROCEDURE 46
Check fuel pump circuit.
Measure at the fuel pump connector D-18.

Disconnect the connector and measure at the harness side.

Continuity between 1 and earth
OK:ContinuityNGCheck the following connector:
D-04NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between fuel pump and earth, and repair
if necessary.
OK
Check the following connectors: D-04, B-64NG
Repair OKCheck trouble symptom.
NG
Check the harness wire between terminal for fuel pump drive and
fuel pump connector.NG
Repair
OK
Replace the fuel pump.