Page 1024 of 2389

TROUBLESHOOTING
TROUBLESHOOTING HINTS
1. Engine troubles is usually not caused by the EFI system.
When troubleshooting, always first check the condition of
the other systems.
(a) Electronic source
wBattery
wFusible links
wFuses
(b) Body ground
(e) Fuel supply
wFuel leakage
wFuel filter
wFuel pump
(d) Ignition system
wSpark plugs
wHigh±tension cords
wDistributor
wIgnition coil
wIgniter
(e) Air induction system
wVacuum leaks
(f) Emission control system
wPCV system
wEGR system
(g) Others
wIgnition timing (ESA system)
wdle speed (ISC system)
wetc.
2. The most frequent cause of problems is simply a bad contact
in wiring connectors. Always check that connections are
secure.
When inspecting the connector, pay particular attention to
the following points:
(a) Check to see that the terminals are not bent.
(b) Check to see that the connector is pushed in completely and
locked.
(e) Check to see that there is no signal change when the con-
nector is slightly tapped or wiggled.
3. Troubleshoot sufficiently for other causes before replacing
the ECU, as the ECU is of high quality and it is expensive.
± EFI SYSTEMTroubleshootingFI±10
Page 1026 of 2389

1. Spark plugs
2. Compression pressure
Minimum: 10.0 kg/cm2
(142 psi, 981 kPa)
at 250 rpm
3. Valve clearance
Standard:
3F±FE I N 0.19 ± 0.29 mm
(0.007 ± 0.011 in.)
EX 0.28 ± 0.38 mm
(0.011 ± 0.015 in.)
2VZ±FE IN 0.13 0.23 mm
(0±005 ± 0.009 in.)
EX 0.27± 0.37 mm
(0.011 ± 0.015 in.)
CHECK FUEL SUPPLY TO INJECTOR
1. Fuel tank
2. Fuel pressure in fuel line
(1) Connect terminals +B and FP of the check connector.
(2) Fuel pressure at fuel hose of fuel filter can be felt. (See
page FI±70)
CHECK IGNITION TIMING
1. Connect terminals TE1 and E1 of the check connector.
2. Check ignition tinning.
Standard: 10° BTDC @ idle CHECK FUEL PUMP SWITCH IN AIR FLOW
METER
Check continuity between terminals FC and E1
while measuring plate of air flow meter is open.1. Fuel line ± leakage ± deformation
2. Fuse(s)
3. Fuel pump (See page FI±68)
4. Fuel filter
5. Fuel pressure regulator
(See page FI±84 or 86) 1. Injector(s) shorted or leaking
2. Injector wiring ± short circuited
3. Cold start injector ± leakage
(See page FI±78 or 81)
4. Cold start injector time switch
(See page FI±124)CHECK SPARK PLUGS
Standard: 1.1 mm (0.043 in.)
HINT: Check compression pressure and
valve clearance if necessary.
Ignition timing ± Adjust
(See page IG±17 or 21)
OK CONTINUED FROM PAGE FI±11
OK CONTINUED ON PAGE FI±13
Air flow meter (See page FI±104)
BAD
All
Plugs
WET
BAD
BADBAD
± EFI SYSTEMTroubleshootingFI±12
Page 1028 of 2389

1. Spark plugs
2. Compression pressure
Minimum: 10.0 kg/cm 2
(142 psi, 981 kPa)
at 250 rpm
3. Valve clearance
Standard:
3F±FE IN 0.19 ± 0.29 mm
(0.007 ± 0.011 in.)
EX 0.28 ± 0.38 mm
(0.011 ± 0.015 in.)
2VZ±FE IN 0.13 ± 0.23 mm
(0.005 ± 0.009 in.)
EX 0.27± 0.37 mm
(0.011 ± 0.015 in.)
1. Wiring connection
2. Power to ECU
(1) Fusible link(s)
(2) Fuse(s)
(3) ER main relay (See page FI±121)
3. Air flow meter (See page FI±104)
4. Water temp. sensor (See page FI±125)
5. Air temp. sensor (See page FI±104j
6. Injection signal circuit
(1) Injector wiring
(2) ECU (See page FI±130) CHECK IGNITION TIMING
1. Connect terminals TE1 and E1 of the check connector.
2. Check ignition timing.
Standard: 10° BTDC @ idle
CHECK SPARK PLUGS
Standard: 1.1 mm (0.043 in.)
HINT: Check compression pressure and
valve clearance if necessary.
CHECK EFI ELECTRONIC CIRCUIT USING
VOLT/OHMMETER
(See page FI±31)1. Cold start injector (See page FI±78 or 81)
2. Cold start injector time switch
(See page FI±124)
1. Fuel pump (See page FI±68)
2. Fuel filter
3. Fuel pressure regulator
(See page FI±84 or 86) CHECK COLD START INJECTOR
(See page FI±78 or 81)
OK CONTINUED FROM PAGE FI±13
CHECK FUEL PRESSURE
(See page FI±70)Ignition timing ± Adjust
(See page IG±17 or 21)
CHECK INJECTORS
(See page FI±88 or 93)Injection condition
BADBAD
BAD BAD
± EFI SYSTEMTroubleshootingFI±14
Page 1030 of 2389

SYMPTOM ± HIGH ENGINE IDLE SPEED (NO DROP)
HINT (3S±FE): Disconnecting the battery will cause the idling speed data in the ISC to be returned to the initial
idling speed, causing the idling speed to rise above 700 rpm. should this happen, either carry out a driving test,
including stop±go several times at a speed above 10 km/h, or start the engine, idle for 30 seconds and then turn
the engine off repeatedly. By doing this, idle data will be stored in the ISC and the idle rpm will be at specified
value.
1. Spark plugs
2. Compression pressure
Minimum: 10.0 kg/cm2
(142 psi, 981 kPa)
at 250 rpm
3. Valve clearance
Standard:
3F±FE IN 0.19 ± 0.29 mm
0.007 ± 0.011 in.)
EX 0.28 ± 0.38 mm
(0.011 ± 0.015 in.)
2VZ±FE I N 0.13 0.23 mm
(0.005 ± 0.009 in.)
EX 0.27± 0.37 m m
(0.011 0.015 in.)
1. Wiring connection
2. Power to ECU
(1) Fusible link(s)
(2) Fuse(s)
(3) ER main relay (Seepage FI±121)
3. Air flow meter (See page FI±104)
4. Water temp. sensor (See page FI±125)
5. Air temp. sensor (See page FI±104)
6. Injection signal circuit
(1) Injector wiring
(2) ECU (See page FI±I30)
7. Oxygen sensor(s)
(See page FI±129 or 131) CHECK SPARK PLUGS
Standard: 1.1 mm (0.043 in.)
HINT: Check compression pressure and valve
clearance if necessary.
CHECK EFI ELECTRONIC CIRCUIT USING
VOLT/OHMMETER
(See page FI±31 )1. Cold start injector (See page FI±78 or 81)
2. Cold start injector time switch
(See page FI±124)
t . Fuel pump (See page FI±68)
2. Fuel filter
3. Fuel pressure regulator
(See page FI±84 or 86) CHECK COLD START INJECTOR
(See page FI±78 or 81)
CHECK FUEL PRESSURE
(See page FI±70)
OK CONTINUED FROM PAGE FI±15
CHECK INJECTORS
(See page FI±88 or 93)Injection condition
BADBAD
BAD
BAD
± EFI SYSTEMTroubleshootingFI±16
Page 1033 of 2389

1. Spark plugs
2. Compression pressure
Minimum: 10.0 kg/cm
2
(142 psi, 981 kPa)
at 250 rpm
3. Valve clearance
Standard:
3F±FE 1N 0.19 ± 0.29 mm
(0.007 ± 0.011 in.)
EX 0.28 ± 0.38 mm
(0.011 0.015 in.)
2VZ±FE I N 0.13 ± 0.23 mm
(0.005 ± 0.009 in.)
EX 0.27± 0.37 mm
(0.011 ± 0.015 in.)
1. Throttle position sensor
(See page FI±106, 110 or 112)
2. Injection signal circuit
(1) Injector wiring
(2) Fuel cut RPM (See page FI±135)
(3) ECU (See page FI±130)
3. Oxygen sensor(s)
(See page FI±129 or 131)
CHECK IGNITION TIMING
1. Connect terminals TE 1 and E 1 of the check
connector.
2. Check ignition tinning.
Standard: 10
° BTDC @ idle
CHECK SPARK PLUGS
Standard: 1.1 mm (0.043 in.)
HINT: Check compression pressure and
valve clearance if necessary.
SYMPTOM ± MUFFLER EXPLOSION (AFTER FIRE)±Rich Fuel Mixture±Misfire
CHECK EFI ELECTRONIC CIRCUIT USING
VOLT/OHMMETER
(See page FI±31)
1. Cold start injector (See page FI±78 or 81)
2. Cold start injector time switch
(See page FI±124)
CHECK DIAGNOSIS SYSTEM
Check for output of diagnosis code.
(See page FI±22)
CHECK COLD START INJECTOR
(See page FI±78 or 81)
Fuel pressure regulator (See page FI±84 or 86)CHECK FUEL PRESSURE
(See page FI±70)
Diagnostic code(s) (See page FI±25 or 27)
Ignition timing ± Adjust
(See page IG±17 or 21)
CHECK INJECTORS
(See page FI±88 or 93)Injectors ± Leakage Malfunction
code(s)
Normal code
BAD
BAD
BADBAD
± EFI SYSTEMTroubleshootingFI±19
Page 1035 of 2389
1. Spark plug
2. Compression pressure
Minimum: 10.0 kg/cm
2
(142 psi, 981 kPa)
at 250 rpm
3. Valve clearance
Standard:
3F±FE IN 0.19±0.29 mm
(0.007 ± 0.011 in.)
EX 0.28 ± 0.38 mm
(0.011 ± 0.015 in.)
2VZ±FE IN 0.13±0.23
(0.005 ± 0.009 in.)
EX 0.27± 0.37 mm
(0.011 ± 0.015 in.)
1. Wiring connection
2. Power to ECU
(1) Fusible link(s)
(2) Fuse(s)
(3) ER main relay (See page FI±121)
3. Air flow meter (See page FI±104)
4. Water temp. sensor (See page FI±125)
5. Air temp. sensor (See page FI±104)
6. Throttle position sensor
(See page FI±106, 110 or 112)
7. Injection signal circuit
(1) Injector wiring
(2) ECU (See page FI±130)
CHECK SPARK PLUGS
Standard: 1.1 mm (0±043 in.)
HINT: Check compression pressure and
valve clearance if necessary.
CHECK EFI ELECTRONIC CIRCUIT USING
VOLT/OHMMETER
(See page FI±31) OK CONTINUED FROM PAGE FI±20
BAD
± EFI SYSTEMTroubleshootingFI±21
Page 1072 of 2389
Check that there is specified voltage between ECU terminal VF
and body ground.
Check for suction of air into exhaust
system.Check wiring between ECU terminal E1 and body ground.
Check wiring between oxygen sensors and
ECU connectors.There is no voltage between ECU terminals VF and E1.
Check for air leak from air intake system.
Check distributor and ignition system.
Check operation of oxygen sensors. Check cold start injector±.
Replace oxygen sensors.* Rich malfunction only Check fuel pressure.
Check air flow meter.Check spark plugs.Repair or replace.
Repair air suction.
Repair or replace.
Repair or replace. Repair or replace.
Repair or replace.
Repair or replace. Repair or replace. Try another ECU.
Check injectors.
System normal.Repair air leak.
Repair wiring. BAD
BADBADBADBAD
BADBAD
BAD BADBAD
BAD
± EFI SYSTEMTroubleshooting with Volt OhmmeterFI±48
Page 1090 of 2389
Check that there is specified voltage between ECU terminals VF
and body ground. ¿ There is no voltage between ECU terminals VF and E 1.
Check wiring between ECU terminal E i and body ground.
Check for suction of air into exhaust system.
Check wiring between oxygen sensors and
ECU connectors. ¿¿ Check operation of oxygen sensors.Check for air leak from air intake system.
Check cold start injector.Check distributor and ignition system.
Replace oxygen sensors.* Rich malfunction only Check fuel pressure.
Check air flow meter.Check spark plugs.Repair air suction.
Repair or replace. Repair or replace_Repair or replace.
Repair or replace.
Repair or replace.Repair or replace.
Repair or replace. Try another ECU.
Check injectors.
System normal.Repair air leak.
Repair wiring. BAD
BAD
BADBADBAD BAD
BAD
BAD
BAD BADBAD
± EFI SYSTEMTroubleshooting with Volt OhmmeterFI±66