1999 MITSUBISHI LANCER EVOLUTION VI fuel
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MPI – Troubleshooting13-22
INSPECTION PROCEDURE 5
No initial combustion (starting impossible)
Probable cause
In cases such as the above, the cause is probably that a spark plug is defective,
or that the supply of fuel to the combustion chamber is defective.
In addition, foreign materials (water, kerosene, etc.) may be mixed with the fuel.Malfunction of the ignition system
Malfunction of the fuel pump system
Malfunction of the injectors
Malfunction of the engine-ECU
Foreign materials in fuel
Check system voltage when cranking.
OK:8 V or higherNGCheck the battery.
OK
MUT-II: Inspection of no initial combustion.
(Refer to P.13-47, INSPECTION PROCEDURE 37.)
OK
Can any sound be heard from the injectors when cranking (check
using a soundscope)?NGCheck the injector system. (Refer to P.13-15, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Ignition system: Inspection of no initial combustion.
(Refer to P.13-47, INSPECTION PROCEDURE 38.)
OK
Check the following items.
Check the ignition coil, spark plugs, spark plug cables.
Check if the injectors are clogged.
Check if foreign materials (water, alcohol, etc.) got into fuel.
Check the compression pressure.
Page 135 of 558
MPI – Troubleshooting13-23
INSPECTION PROCEDURE 6
Initial combustion but no complete combustion
(starting impossible)
Probable cause
In such cases as the above, the cause is probably that the spark plugs are generating
sparks but the sparks are weak, or the initial mixture for starting is not appropriate.Malfunction of the ignition system
Malfunction of the injector system
Foreign materials in fuel
Poor compression
Malfunction of the engine-ECU
Check system voltage when cranking.
OK:8 V or higherNGCheck the battery.
OK
MUT-II: Check if uncompleted combustion occurs.
(Refer to P.13-48, INSPECTION PROCEDURE 39.)
OK
Can any sound be heard from the injectors when cranking (check
using a soundscope)?NGCheck the injector system, (Refer to P.13-15, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Is starting good if the engine is cranked with the accelerator pedal
slightly depressed?Ye sCheck ISC servo for op-
eration sound. NGCheck the ISC servo sys-
tem. (Refer to P.13-44, IN-
SPECTION PROCE-
DURE 33.)
OK
Clean the throttle valve area.
Adjust the fixed SAS. (Refer to P.13-30.)*
No
Check the ignition timing when cranking.
OK:Approx. 5BTDCNGCheck 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 injectors for clogging and leakage.
Check the compression pressure.
Check fuel lines for clogging.
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).
Page 136 of 558
MPI – Troubleshooting13-24
INSPECTION PROCEDURE 7
Long time to start (Improper starting)
Probable cause
In cases such as the above, the cause is probably that the spark is weak and ignition
is difficult, the initial mixture for starting is not appropriate, or sufficient compression
pressure is not being obtained.Malfunction of the ignition system
Malfunction of the injector system
Inappropriate gasoline use
Poor compression
Check system voltage when cranking
OK:8 V or higherNGCheck the battery.
OK
MUT-II: Check if uncomplete combustion occurs.
(Refer to P.13-48, INSPECTION PROCEDURE 39.)
OK
Can any sound be heard from the injectors when cranking (check
using a soundscope)?NGCheck the injector system. (Refer to P.13-15, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Check the ignition timing when cranking.
OK:Approx. 5BTDCNGCheck 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 injectors for clogging and leakage.
Check the compression pressure.
Check if foreign materials (water, alcohol, etc.) got into fuel.
Page 137 of 558
MPI – Troubleshooting13-25
INSPECTION PROCEDURE 8
Unstable idling (Rough idling, hunting)
Probable cause
In cases as the above, the cause is probably that the ignition system, air/fuel mixture,
idle speed control (ISC) or compression pressure is defective.
Because the range of possible causes is broad, inspection is narrowed down to simple
items.Malfunction of the ignition system
Malfunction of air-fuel ratio control system
Malfunction of the ISC servo system
Poor compression
Drawing air into exhaust system
Secondary air backflow 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 Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13-8, INSPECTION CHART FOR DIAGNOSIS CODES.
No
Does idling speed fluctuate excessively?Ye sCheck if hunting occurs.
(Refer to P.13-48, INSPECTION PROCEDURE 40.)
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.NGCheck the injector system. (Refer to P.13-15, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
MUT-II: Check if idling speed is unstable.
(Refer to P.13-49, INSPECTION PROCEDURE 41.)
OK
Check the ignition timing.
(Refer to GROUP 11 – Engine Adjustment.)*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 back flow of secondary air into the intake system.)
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).
Page 140 of 558
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).
Page 141 of 558
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 signalSecondary 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).
Page 142 of 558
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.
Page 143 of 558
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.