fuel MITSUBISHI LANCER EVOLUTION VI 1999 Owner's Manual

MPI – Troubleshooting13-28
INSPECTION PROCEDURE 11
When the engine is cold, it stalls at idling. (Die out)
Probable cause
In such cases as the above, the cause is probably that the air/fuel mixture is inappropriate
when the engine is cold, or that the intake air volume is insufficient.
Malfunction of the ISC servo system

Malfunction of the throttle body

Malfunction of the injector system

Malfunction of the ignition system
Were the battery terminals disconnected recently?Ye sAfter warming-up, let the engine run at idling for about 10 minutes.
No
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
OK
Check the fuel pressure. (Refer to P.13-30.)*
OK
Check the ignition timing.
(Refer to GROUP 11 – Engine Adjustments.)*NGCheck that the crank angle sensor and the timing belt cover are
installed properly.
OK
Check the following items.

Check the ignition coil, spark plugs, spark plug cables.

Check the compression pressure.

Check the engine oil viscosity.
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
Check the injector for operation sound.NGCheck the injector system. (Refer to P.13-15, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
Ye s
Check the ISC servo for operation sound.NGCheck the ISC servo system.
(Refer to P.13-44, INSPECTION PROCEDURE 33.)
No
Is engine-idling stable after the warming-up?NoCheck for unstable idling (Rough idling, hunting).
(Refer to P.13-25, INSPECTION PROCEDURE 8.)
No
Does the engine stall right after the accelerator pedal is released?Ye sClean the throttle valve
area.Adjust the fixed SAS.
(Refer to P.13-30.)*
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.)
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-29
INSPECTION PROCEDURE 12
When the engine is hot, it stalls at idling. (Die out)
Probable cause
In such cases as the above, the cause is probably that ignition system, air/fuel mixture,
idle speed control (ISC) or compression pressure is defective.
In addition, if the engine suddenly stalls, the cause may also be a defective connector
contact.
Malfunction of the ignition system

Malfunction of air-fuel ratio control system

Malfunction of the ISC servo system

Drawing air into intake system

Improper connector contact

Backflow of secondary air to the intake system
Were the battery terminals disconnected recently?Ye sAfter warming-up, let the engine run at idling for about 10 minutes.
No
MUT-II Diagnosis code
Are diagnosis codes displayed?Ye sRefer to P.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
No
Check the ISC servo for operation sound.NGCheck the ISC servo system.
(Refer to P.13-44, INSPECTION PROCEDURE 33.)
OK
Check the injector for operation sound.NGCheck the injector system. (Refer to P.13-15, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Does the engine stall right after the accelerator pedal is released?Ye sClean the throttle valve
area.Adjust the fixed SAS.
(Refer to P.13-30.)*
No
Does the engine stall easily again?NoWhile carrying out an intermittent malfunction simulation test (Refer
to GROUP 00 – Points to Note for Intermittent Malfunctions.), check
for sudden changes in the signals shown below.

Crank angle sensor signal

Injector drive signal

Fuel pump drive signal

Air flow sensor signal
Secondary ignition signal

Engine-ECU power supply
voltage
Ye s
MUT-II: Engine stalling inspection when the engine is warm and
idling. (Refer to P.13-50, INSPECTION PROCEDURE 42.)
OK
Check the ignition timing.
(Refer to GROUP 11 – ENGINE ADJUSTMENTS.)*NGCheck that the crank angle sensor and the timing belt cover are
installed properly.
OK
Check the following items.

Check the ignition coil, spark plugs, spark plug cables.

Check the secondary air supply system. (Ensure that there is no backflow of secondary air into the intake system.)

Check if the injectors are clogged.

Check the compression pressure.

Check if foreign materials (water, alcohol, etc.) got into fuel.
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-30
INSPECTION PROCEDURE 13
The engine stalls when starting the car. (Pass out)
Probable cause
In cases such as the above, the cause is probably misfiring due to a weak spark,
or an inappropriate air/fuel mixture when the accelerator pedal is depressed.
Drawing air into intake system

Malfunction of the ignition system
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
No
Check the following items.

Check the ignition coil, spark plugs, spark plug cables.

Check if air was drawn into the intake system.
Broken intake manifold gasket
Broken or disconnected vacuum hose
Improper operation of the PCV valve
Broken air intake hose
INSPECTION PROCEDURE 14
The engine stalls when decelerating.
Probable cause
In cases such as the above, the cause is probably that the intake air volume is insufficient
due to a defective idle speed control (ISC) servo system.
Malfunction of the ISC servo system
No
MUT-II Data list
26 Idle position switch (Refer to P.13-XX.)NGCheck the idle position switch system.
(Refer to P.13-XX, INSPECTION PROCEDURE 26.)
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
45 ISC servo position

Is the idle speed control (ISC) servo position drops to 0–2
steps when decelerating (engine r/min less than 1,000)?Ye sCheck the vehicle speed sensor system. (Refer to P.13-13, INSPEC-
TION PROCEDURE FOR DIAGNOSIS CODE 24.)
No
Check the following items.

Check the ignition coil, spark plugs, spark plug cables.

Clean the throttle valve area.

Check and adjust the fixed SAS.
No
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.)
No
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
Were the battery terminals disconnected recently?Ye sAfter warming-up, let the engine run at idling for about 10 minutes.

MPI – Troubleshooting13-31
INSPECTION PROCEDURE 15
Hesitation, sag or stumble
Probable cause
In cases such as the above, the cause is probably that ignition system, air/fuel mixture
or compression pressure is defective.
Malfunction of the ignition system

Malfunction of air-fuel ratio control system

Malfunction of the fuel supply system

Poor compression

Malfunction of the turbocharger system

Malfunction of the secondary air supply system
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
No
Check the injectors for operation sound.NGCheck the injector system. (Refer to P.13-15, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Check the ignition timing.
(Refer to GROUP 11 – Engine Adjustments.)*NGCheck that the crank angle sensor and the timing belt cover are
installed properly.
OK
MUT-II: Check if hesitation, sag, stumble or poor acceleration
occurs. (Refer to P.13-51, INSPECTION PROCEDURE 43.)
OK
Check the fuel pressure. (Refer to P.13-30.)*
OK
Check the following items.

Check the ignition coil, spark plugs, spark plug cables.

Check the turbocharger boost pressure.

Check the boost pressure control system.

Check the turbocharger turbine wheel for smooth rotation.

Check the compression pressure.

Check the fuel filter or fuel line for clogging.

Check the secondary air supply system.
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).
INSPECTION PROCEDURE 16
The feeling of impact or vibration when accelerating
Probable cause
In cases such as the above, the cause is probably that there is an ignition leak
accompanying the increase in the spark plug demand voltage during acceleration.
Malfunction of the ignition system
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
No
Check the following items.

Check the ignition coil, spark plugs, spark plug cables.

Check for occurrence of ignition leak.

MPI – Troubleshooting13-32
INSPECTION PROCEDURE 17
The feeling of impact or vibration when decelerating
Probable cause
Malfunction of the ISC servo system is suspected.
Malfunction of the ISC servo system
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
No
Check the ISC servo for operation sound.NGCheck the ISC servo system.
(Refer to P.13-44, INSPECTION PROCEDURE 33.)
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
26 Idle position switch (Refer to P.13-58.)NGCheck the idle position switch system.
(Refer to P.13-38, INSPECTION PROCEDURE 26.)
OK
Clean the throttle valve area.
INSPECTION PROCEDURE 18
Poor acceleration
Probable cause
Defective ignition system, abnormal air-fuel ratio, poor compression pressure, etc.
are suspected.
Malfunction of the ignition system

Malfunction of air-fuel ratio control system

Malfunction of the fuel supply system

Poor compression pressure

Clogged exhaust system

Malfunction of the turbocharger system
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
No
Check the injectors for operation sound.NGCheck the injector system. (Refer to P.13-15, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Check the ignition timing.
(Refer to GROUP 11 – Engine Adjustments.)*NGCheck that the crank angle sensor and the timing belt cover are
installed properly.
OK
MUT-II: Check if hesitation, sag, stumble or poor acceleration occur.
(Refer to P.13-51, INSPECTION PROCEDURE 43.)
OK
Check the fuel pressure. (Refer to P.13-30.)*
OK
Check the following items.

Check the ignition coil, spark plugs, spark plug cables.

Check the turbocharger boost pressure.

Check the boost pressure control system.

Check the turbocharger turbine wheel for smooth rotation.

Check the compression pressure.

Check the fuel filter or fuel line for clogging.

Broken air intake hose

Clogged air cleaner

Clogged exhaust system
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-33
INSPECTION PROCEDURE 19
Surge
Probable cause
Defective ignition system, abnormal air-fuel ratio, etc. are suspected.
Malfunction of the ignition system

Malfunction of air-fuel ratio control system
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
No
Check the injectors for operation sound.NGCheck the injector system. (Refer to P.13-15, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Check the ignition timing.
(Refer to GROUP 11 – Engine Adjustments.)*NGCheck that the crank angle sensor and the timing belt cover are
installed properly.
OK
MUT-II: Check if surge occurs.
(Refer to P.13-52, INSPECTION PROCEDURE 44.)
OK
Check the fuel pressure. (Refer to P.13-30.)*
OK
Check the following items.

Check the ignition coil, spark plugs, spark plug cables.

Check the waste gate actuator.
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).
INSPECTION PROCEDURE 20
Knocking
Probable cause
In cases as the above, the cause is probably that the detonation control is defective
or the heat value of the spark plug is inappropriate.
Defective detonation sensor

Inappropriate heat value of the spark plug
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
No
Does knocking occur when driving with the sensor disconnected?
At this time, use the MUT-II to check if the timing is retarded
compared to when the detonation sensor connector is con-
nected.NoCheck the detonation sensor system. (Refer to P.13-15, INSPEC-
TION PROCEDURE FOR DIAGNOSIS CODE 31.)
Ye s
Check the following items.

Spark plugs

Check if foreign materials (water, alcohol, etc.) got into fuel.
INSPECTION PROCEDURE 21
Dieseling
Probable cause
Fuel leakage from injectors is suspected.
Fuel leakage from injectors
Check the injectors for fuel leakage.

MPI – Troubleshooting13-34
INSPECTION PROCEDURE 22
Too high CO and HC concentration when idling
Probable cause
Abnormal air-fuel ratio is suspected.
Malfunction of the air-fuel ratio control system

Deteriorated catalyst
Check trouble symptom.
No
Check the ignition timing.
(Refer to GROUP 11 – Engine Adjustments.)*NGCheck that the crank angle sensor and the timing belt cover are
installed properly.
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
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
11 Oxygen sensor
OK:600–1,000 mV when racing suddenlyNGCheck the oxygen sensor system. (Refer to P.13-15, INSPECTION
PROCEDURE FOR DIAGNOSIS CODE 31.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Repeat 0–400 mV and 600–1,000 mV alternately when
idling.OK
NG
Check the fuel pressure. (Refer to P.13-30.)*
OK
NG
Check the following items.

Check the injectors for operation sound.

Check the injectors for fuel leakage.

Check the ignition coil, spark plugs, spark plug cables.

Check the compression pressure.

Check the positive crankcase ventilation system.

Check the evaporative emission control system.
Check the trouble symptom.
NG
Replace the catalytic converter.
Replace the oxygen sensor.
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-36
INSPECTION PROCEDURE 25
Fuel pump system
Probable cause
The engine-ECU turns the control relay ON when the engine is cranking or running,
and this supplies power to drive the fuel pump.
Malfunction of the fuel pump relay

Malfunction of the fuel pump

Improper connector contact, open or short-circuited
harness wire

Malfunction of the engine-ECU
OK
Check the harness wire between resistor connector and fuel pump
drive terminal and between fuel pump relay No.2 connector and
fuel pump drive terminal, and repair if necessary.
OK
Check the resistor. (Refer to P.13-34.)*NG
Replace
OK
Measure at the resistor connector A-124.

Disconnect the connector.

Voltage between 1 and earth

MUT-II Actuator test: Fuel pump relay No.2 drive
OK:System voltageNGCheck the harness wire between fuel pump relay No.2 and resistor
connector, and repair if necessary.
OK
Measure at the engine-ECU connector B-60.

Connect the connector.

Voltage between 39 and earth

MUT-II Actuator test: Fuel pump drive
OK:System voltageNGCheck the harness wire between fuel pump relay No.2 and
engine-ECU connector, and repair if necessary. NG
Check the harness wire between fuel pump relay and fuel pump
relay No.2 connector, and repair if necessary.
OK
Measure at the fuel pump relay No.2 connector A-123.

Disconnect the connector.

Voltage between each of 3 and 5 and earth

MUT-II Actuator test: Fuel pump drive
OK:System voltage
OK
Check the fuel pump relay No.2. (Refer to P.13-68)NG
Replace
OK
Check the following connectors:
D-18, D-04, B-64, A-124, A-123, B-59, B-60NG
Repair
OK
Measure at the fuel pump relay connector B-28.

Connect the connector.

Voltage between 1 and earth

MUT-II Actuator test: Fuel pump drive
OK:System voltageNGCheck the fuel pump drive control circuit.
(Refer to P.13-54, INSPECTION PROCEDURE 47.)
OK
Check the fuel pump relay. (Refer to P.13-68.)NG
Replace
Check the fuel pump operation by applying the system voltage
to the fuel pump drive terminal.NGCheck the fuel pump circuit.
(Refer to P.13-53, INSPECTION PROCEDURE 46.)
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-37
INSPECTION PROCEDURE 25
Fuel pump system
Probable cause

The engine-ECU turns the fuel pump relay ON when the engine is cranking or
running, and this supplies power to drive the fuel pump.

The engine-ECU supplies power to the fuel pump through the resistor at low load
operations. It supplies power directly to the fuel pump at high load operations
to increase the pump output.
Malfunction of the fuel pump relay

Malfunction of the fuel pump relay No.2

Malfunction of the fuel pump

Malfunction of fuel pump resistor

Improper connector contact, open or short-circuited
harness wire

Malfunction of engine-ECU
OK
Check the fuel pump drive control circuit.
(Refer to P.13-54, INSPECTION PROCEDURE 47.)
Check the harness wire between fuel pump
relay No.2 and fuel pump relay connector,
and repair if necessary.NG
Repair
NG
OK
Check trouble symptom.
NG
Check the harness wire between fuel pump relay No.2 and
engine-ECU connector, and repair if necessary.
OK
Check trouble symptom.
NG
Replace the engine-ECU.
OK
Check trouble symptom.
OK
Check the following connector: B-60NG
Repair
OK
Measure at the engine-ECU connector B-60.

Disconnect the connector, and measure at the harness side.

Voltage between 39 and earth

MUT-II Actuator test: 07 Fuel pump
OK:System voltageNGCheck the following connector: A-123NG
Repair NG
Check the harness wire between fuel pump resistor and fuel pump
relay connector, and repair if necessary.
OK
Measure at the fuel pump resistor connector A-124.

Disconnect the connector, and measure at the harness side.

Voltage between 1 and earth

MUT-II Actuator test: 13 Fuel pump relay No.2
OK:System voltage
OK
Measure at the fuel pump relay No.2 connector A-123.

Disconnect the connector, and measure at the harness side.

Disconnect the fuel pump resistor connector.

Voltage between each of 1 and 3 and earth

MUT-II Actuator test: 07 Fuel pump drive
OK:System voltageNGCheck the following connector: B-28NG
Repair
OK
Check the fuel pump relay No.2 and fuel pump resistor.
(Refer to P.13-68.)NG
Replace
OK
Check the fuel pump relay. (Refer to P.13-68.)NG
Replace
Check the harness wire between fuel pump resistor and fuel pump
connector, and repair if necessary.
OK
Perform fuel pump operation check.

Disconnect the fuel pump resistor connector.

Apply system voltage to terminal No.2 of the harness side
connector.
OK:Fuel pump operates.NG
Perform fuel pump operation check.

Disconnect the fuel pump relay No.2 connector.

Apply system voltage to terminal No.2 of the harness side
connector.
OK:Fuel pump operates.NGCheck the fuel pump circuit.
(Refer to P.13-54, INSPECTION PROCEDURE 46.)

MPI – Troubleshooting13-38
INSPECTION PROCEDURE 26
Idle position switch system
Probable cause
The idle position switch inputs the condition of the accelerator pedal, i.e. whether
it is depressed or released (HIGH/LOW), to the engine-ECU.
The engine-ECU controls the idle speed control servo based on this input.
Maladjustment of the accelerator cable

Maladjustment of the fixed SAS

Maladjustment of the idle position switch and throttle
position sensor

Improper connector contact, open or short-circuited
harness wire

Malfunction of the engine-ECU
Check the idle position switch. (Refer to P.13-30.)*NGReplace the throttle position sensor.
OK
Measure at the throttle position sensor connector A-16.

Disconnect the connector, and measure at the harness side.

Voltage between 3 and earth (Ignition switch: ON)
OK:4 V or higher

Continuity between 4 and earth
OK:ContinuityNGCheck the following
connector: B-62NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between engine-ECU and throttle position
sensor connector.
OK
Replace the engine-ECU.
NG
Repair
OK
Check the following
connector: A-16NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).
INSPECTION PROCEDURE 27
Ignition switch-ST system
Probable cause
The ignition switch-ST inputs a HIGH signal to the engine-ECU while the engine is
cranking.
The engine-ECU controls fuel injection, etc. during starting based on this input.
Malfunction of ignition switch

Improper connector contact, open or short-circuited
harness wire

Malfunction of the engine-ECU
Measure at the engine-ECU connector B-62.

Disconnect the connector, and measure at the harness side.
1. Voltage between 71 and earth (Ignition switch: START)
OK:8V
2. Continuity between 91 and earth
OK:Continuity1. NGCheck the following
connector: B-64NG
Repair
OK
Check trouble symptom.
NG
Check harness wire be-
tween the engine-ECU
and ignition switch con-
nector.NG
Repair
OK
Check the ignition switch.
2. NG
Check the harness wire between engine-ECU connector (terminal
No.91) and earth, and repair if necessary.
OK
Check the following
connector: B-62NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.