MPI ± Troubleshooting13A-32
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?Ye sAfter warming-up, let the engine run at idling for 10 minutes.
No
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
OK
Check the fuel pressure. (Refer to P.13A-81.)
OK
Check the ignition timing.
(Refer to GROUP 11 ± On-vehicle Service.)NGCheck that the distributor is installed properly.
OK
Check the following items.
Check the ignition coil, spark plugs, spark plug cables. (Refer to GROUP 16 ± On-vehicle Service.)
Check the compression pressure. (Refer to GROUP 11 ± On-vehicle Service.)
Check the engine oil viscosity.
OK
MUT-II Data list
26 Idle position switch (Refer to P.13A-57.)NGCheck the idle position switch system.
(Refer to P.13A-40, INSPECTION PROCEDURE 25.)
OK
Check the injector for operation sound.NGCheck the injector system. (Refer to P.13A-19, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
Ye s
Check the ISC servo for operation sound. (Refer to P.13A-90.)NGCheck the ISC servo system.
(Refer to P.13A-45, INSPECTION PROCEDURE 31.)
No
Is engine-idling stable after the warming-up?NoCheck if the unstable idling (Rough idling, hunting).
(Refer to P.13A-29, INSPECTION PROCEDURE 8.)
No
Does the engine stall right after the accelerator pedal is released?Ye sClean the throttle valve
area. (Refer to P.13A-78.)Check and adjust the
fixed SAS.
(Refer to P.13A-79.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13A-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13A-14, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Actuator test
10 EGR control solenoid valve (Refer to P.13A-62.)NGCheck the EGR control solenoid valve system. (Refer to P.13A-46,
INSPECTION PROCEDURE 33.)
MPI ± Troubleshooting13A-33
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 system
Drawing air into intake system
Improper connector contact
Were the battery terminals disconnected?Ye sAfter warming-up, let the engine run at idling for 10 minutes.
No
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
No
Check the ISC servo for operation sound. (Refer to P.13A-90.)NGCheck the ISC servo system.
(Refer to P.13A-45, INSPECTION PROCEDURE 31.)
OK
Check the injector for operation sound.NGCheck the injector system. (Refer to P.13A-19, 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. (Refer to P.13A-78.)Check and adjust the
fixed SAS.
(Refer to P.13A-79.)
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
Air flow sensor signal
Injector drive signalPrimary and secondary
ignition signal
Fuel pump drive signal
Engine-ECU power supply
voltage
Ye s
MUT-II: Engine stalling inspection when the engine is warm and
idling. (Refer to P.13A-50, INSPECTION PROCEDURE 39.)
OK
Check the ignition timing.
(Refer to GROUP 11 ± On-vehicle Service.)NGCheck that the distributor is installed properly.
OK
Check the following items.
Check the ignition coil, spark plugs, spark plug cables. (Refer to GROUP 16 ± On-vehicle Service.)
Check if the injectors are clogged.
Check the compression pressure. (Refer to GROUP 11 ± On-vehicle Service.)
Check if foreign materials (water, alcohol, etc.) got into fuel.
MPI ± Troubleshooting13A-35
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
Malfunction of the EGR control solenoid valve system
Poor compression
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
No
Check the injectors for operation sound.NGCheck the injector system. (Refer to P.13A-19, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Check the ignition timing.
(Refer to GROUP 11 ± On-vehicle Service.)NGCheck that the distributor is installed properly.
OK
MUT-II: Check if hesitation, sag, stumble or poor acceleration occur.
(Refer to P.13A-51, INSPECTION PROCEDURE 40.)
OK
Check the fuel pressure. (Refer to P.13A-81.)
OK
Check the following items.
Check the ignition coil, spark plugs, spark plug cables. (Refer to GROUP 16 ± On-vehicle Service.)
Check the EGR control system. (Refer to GROUP 17 ± Emission Control System.)
Check the compression pressure. (Refer to GROUP 11 ± On-vehicle Service.)
Check the fuel filter or fuel line for clogging.
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.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
No
Check the following items.
Check the ignition coil, spark plugs, spark plug cables. (Refer to GROUP 16 ± On-vehicle Service.)
Check for occurrence of ignition leak.
MPI ± Troubleshooting13A-36
INSPECTION PROCEDURE 17
The feeling of impact or vibration when decelerating.
Probable cause
Malfunction of the ISC system is suspected.Malfunction of the ISC system
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
No
Check the ISC servo for operation sound. (Refer to P.13A-90.)NGCheck the ISC servo system.
(Refer to P.13A-45, INSPECTION PROCEDURE 31.)
OK
MUT-II Data list
14 Throttle position sensor (Refer to P.13A-57.)NGCheck the throttle position sensor system. (Refer to P.13A-13, IN-
SPECTION PROCEDURE FOR DIAGNOSIS CODE 14.)
OK
MUT-II Data list
26 Idle position switch (Refer to P.13A-57.)NGCheck the idle position switch system.
(Refer to P.13A-40, INSPECTION PROCEDURE 25.)
OK
Clean the throttle valve area. (Refer to P.13A-78.)
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
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
No
Check the injectors for operation sound.NGCheck the injector system. (Refer to P.13A-19, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Check the ignition timing.
(Refer to GROUP 11 ± On-vehicle Service.)NGCheck that the distributor is installed properly.
OK
MUT-II: Check if hesitation, sag, stumble or poor acceleration occur.
(Refer to P.13A-51, INSPECTION PROCEDURE 40.)
OK
Check the fuel pressure. (Refer to P.13A-81.)
OK
Check the following items.
Check the ignition coil, spark plugs, spark plug cables. (Refer to GROUP 16 ± On-vehicle Service.)
Check the compression pressure. (Refer to GROUP 11 ± On-vehicle Service.)
Check the fuel filter or fuel line for clogging.
Broken air intake hose
Clogged air cleaner
MPI ± Troubleshooting13A-37
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
Malfunction of the EGR control solenoid valve system
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
No
Check the injectors for operation sound.NGCheck the injector system. (Refer to P.13A-19, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Check the ignition timing.
(Refer to GROUP 11 ± On-vehicle Service.)NGCheck that the distributor is installed properly.
OK
MUT-II: Check if surge occurs.
(Refer to P.13-52, INSPECTION PROCEDURE 41.)
OK
Check the fuel pressure. (Refer to P.13A-81.)
OK
Check the following items.
Check the ignition coil, spark plugs, spark plug cables. (Refer to GROUP 16 ± On-vehicle Service.)
Check the EGR control system. (Refer to GROUP 17 ± Emission Control System.)
INSPECTION PROCEDURE 20
Knocking
Probable cause
In cases as the above, the cause is probably that the heat value of the spark plug
is inappropriate.Inappropriate heat value of the spark plug
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 ± Troubleshooting13A-38
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 ± On-vehicle Service.)NGCheck that the distributor is installed properly.
OK
MUT-II Data list
21 Engine coolant temperature sensor. (Refer to P.13A-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13A-14, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13A-57.)NGCheck the intake air temperature sensor system. (Refer to P.13A-12,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13A-57.)NGCheck the barometric pressure sensor system. (Refer to P.13A-18,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list
11 Oxygen sensor
OK:600 ± 1,000 mV when racing suddenly (Refer to P.13A-57.)NGCheck the oxygen sensor system. (Refer to P.13A-11, INSPECTION
PROCEDURE FOR DIAGNOSIS CODE 11.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Repeat 0 ± 400 mV and 600 ± 1,000 mV alternately when
idling. (Refer to P.13A-57.)OK
NG
Check the fuel pressure. (Refer to P.13A-81.)
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. (Refer to GROUP 16 ± On-vehicle Service.)
Check the compression pressure. (Refer to GROUP 11 ± On-vehicle Service.)
Check the positive crankcase ventilation system. (Refer to GROUP 17 ± Emission Control System.)
Check the purge control system. (Refer to GROUP 17 ± Emission Control System.)
Check the EGR control system. (Refer to GROUP 17 ± 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.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
MPI ± On-vehicle Service13A-83
14. Stop the engine and check change of fuel pressure gauge
reading. Normal if the reading does not drop within 2
minutes. If it does, observe the rate of drop and
troubleshoot and repair according to the table below.
SymptomProbable causeRemedy
Fuel pressure drops gradually after
engine is stopped
Leaky injectorReplace injector
engine is sto ed
Leaky fuel regulator valve seatReplace fuel pressure regulator
Fuel pressure drops sharply
immediately after engine is stoppedCheck valve in fuel pump is held openReplace fuel pump
15. Release residual pressure from the fuel pipe line. (Refer
to P.13A-84.)
16. Remove the fuel pressure gauge and special tool from
the delivery pipe.
Caution
Cover the hose connection with rags to prevent splash
of fuel that could be caused by some residual pressure
in the fuel pipe line.
17. Replace the O-ring at the end of the fuel high pressure
hose with a new one. Furthermore, apply engine oil to
the new O-ring before replacement.
18. Fit the fuel high pressure hose over the delivery pipe
and tighten the bolt to specified torque.
Tightening torque: 5 Nm
19. Check for fuel leaks.
(1) Apply the battery voltage to the fuel pump drive
terminal to drive the fuel pump.
(2) Under fuel pressure, check the fuel line for leaks.
MPI ± Injector13A-93
REMOVAL SERVICE POINT
ADELIVERY PIPE/INJECTOR REMOVAL
Remove the delivery pipe (with the injectors attached to it).
Caution
Care must be taken, when removing the delivery pipe,
not to drop the injector.
INSTALLATION SERVICE POINT
AINJECTOR/FUEL PRESSURE REGULATOR/
HIGH-PRESSURE FUEL HOSE INSTALLATION
(1) Apply a drop of new engine oil to the O-ring.
Caution
Be sure not to let engine oil in the delivery pipe.
(2) While turning the injector, high-pressure fuel hose and
fuel pressure regulator to the right and left, install the
delivery pipe, while being careful not to damage the O-ring.
After installing, check that the hose turns smoothly.
(3) If it does not turn smoothly, the O-ring may be trapped,
remove the fuel pressure regulator and then re-insert
it into the delivery pipe and check once again.
(4) Tighten the high-pressure fuel hose and fuel pressure
regulator to the specified torque.
Tightening torque:
9 Nm (Fuel pressure regulator)
5 Nm (High-pressure fuel hose)