F TROUBLESHOOTING GUIDE
8 ROUGH IDLE/ENGINE STALLS AT IDLE - ALWAYS
bESCRIP- l Engine starts normally but stalls or vibrates excessively at idle in every condition
‘ION TROUBLESHOOTING HINTS]
D Air/Fuel mixture too lean @ Incorrect idle speed
l Air leakage l Idle speed misadjustment l Fuel injection control malfunction l Idle speed control malfunction
*Low fuel line pressure @ One or more spark plugs not firing
3 One or more injectors clogged or not operating @ Low engine compression
3 Low intake air amount @ Airflow meter stuck INSPECTION
1
1
2
3
4
5
6
- Check if “00” is displayed on Self-Diagnosis
Checker with ignition switch ON w page F-82
SYSTEM2ELECT: 1
M v’SELECT SW: A TEST
Check if ECU terminal voltages are OK
MTX...Especially 2D, 20 and 2Q
ATX... Especially 2B, 2E and 3D CT page F-150
Disconnect high-tension lead at idle and check if
engine speed decreases equally at each cylinder
Check for injector operating sound at idle
Check if battery voltage exists at injector connec-
tor (W/R) wire
Check if strong blue spark is visible at discon-
nected high-tension lead
, Yes No Service Code No. displayed
Check for cause (Refer to specified
:heck sequence) “88” flashes
Check ECU terminal IF voltage CT page F-150
Specification: Battery voltage
(Ignition switch ON)
3 If OK, replace ECU w page F-149 3 If not OK, check wiring between
ECU and Self-Diaanosis Checker Yes
Go to next step No
Check for cause Yes
Go to Step 8 No
Go to next step
Go to Step 6
Go to Step 5 Yes
No
Yes
No
Yes
No I-
30 to next step w page F-83
0 page F-151
Check if injector resistance is OK c7 page F-131
Resistance: Approx. 12-l 852
c3 If OK, check wiring between ECU
and injector
c3 If not OK, replace injector w page F-131
Check wiring between ECU and injector
Go to next step
Check high-tension lead w page G-17
Q If OK, check distributor cap and
rotor w page G-22
c3 If not OK, replace high-tension lead
F-42
TROUBLESHOOTING GUIDE F
Fuel line pressure:
265-314 kPa (2.7-3.2 kg/cm’, 36-46 psi)
(Vacuum hose to pressure regulator Ine pressure while pinching
d If fuel line pressure quickly in-
creases, check pressure regulator w page F-129
* If fuel line pressure gradually in-
If not clogged, check fuel pump
maximum pressure w page F-126
Ignition timing (BTDC)
l BP DOHC : go-1 1 o l BP SOHC : 4”-6O
Resistance: 12-l 60
eck wiring between ECU
Engine compression (Minimum):
l BP SOHC :
634 kPa (6.5 kg/cm2, 121 psi)900 rpm
check distributor cap and
23UOFX-02
F-47
TROUBLESHOOTING GUIDE F
No Replace airflow meter
9
Check for injector operating sound at idle Yes Go to Step 11
No Go to next Step
10 Check if battery voltage exists at injector connec- Yes Check if injector resistance is OK CT page F-131
tor (W/R) wire Resistance: 12-l 6fi
c3 If OK, check wiring between ECU
and injector
c3 If not OK, replace injector CT page F-131
No
Check wiring between ECU and injector
11 Check if strong blue spark is visible at discon-
Yes Go to next step
netted high-tension lead
No Check high-tension lead
+ If OK, check distributor cap and
rotor w page G-22
* If not OK, replace high-tension lead
12
Check if spark plugs are OK Yes Check for correct engine compression CT page Bl-10
w page G-16 82-10
Compression (Minimum):
. BP SOHC
834 kPa (8.5 kg/cm2, 121 psi)300 rpm
BON BUILDUP l BP DOHC
883 kPa (9.0 kg/cm*, 128 psi)-300 rpm
l.O-l.lmm ’ B6 DAMAGE AND 932 kPa (9.5 kg/cm’, 135 psi)-300 rpm DETERIORATION
c3 If OK, go to next step
c13 If not OK, check for cause CT page Bl-10
B2-10
No
Clean or replace w page G-18
13
Check for injector leakage Yes Replace injector CT page F-131
w page F-132
No Go
to next step
14 Try known good ECU and check if condition im-
proves cc7 page F-149
23UOFX-030
F-53
F TROUBLESHOOTING GUIDE
15
ENGINE STALLS ON DECELERATION
DESCRIP-
l Engine unexpectedly stops running while decelerating or after deceleration
TION l Idle condition normal
[TROUBLESHOOTING HINTS]
Engine speed drops too much when releasing accelerator or poor connector connection disconnected by deceleration
force
3 Idle speed control malfunction
3 Fuel cut control malfunction @ Idle speed misadjustment
TEP INSPECTION
ACTION
1
Check if idle condition is normal Yes
Go to next step
No Adjust or perform troubleshooting
Nos. 8-11 “ROUGH IDLE” v page F-42
F-48
--
2
Check if “00” is displayed on Self-Diagnosis Yes Go to next step
Checker with ignition switch ON
W page F-82 No
SYSTEM SELECT: 1 Service Code No. displayed
Check for cause (Refer to specified
check sequence) w page F-83
“88” flashes
Check ECU terminal IF voltage LIT= page F-150
Specification: Battery voltage
(Ignition switch ON)
W: SELF TEST + If OK, replace ECU w page F-149
Q If not OK, check wiring between
ECU and Self-Diagnosis Checker
3 Check switches for correct operation with Self-
Yes Go to next step
Diagnosis Checker Monitor Lamp with ignition
switch ON
w page F-105 No
Lamp not ON or OFF with specified
switch
Check for cause (Refer to specified
check sequence) CT page F-106
-,-y/
,’ Lamp always ON
Check wiring between ECU terminal 1 D
and Self-Diagnosis Checker
W: SELF
TEST
4 Check if ECU terminal voltages are OK
Yes Go to next step
MTX...Especially IV, 2D, 20, 2U, 2V and 2Q
ATX... Especially 28, 2E, 30, 3U, and 3V
w page F-150 No Check for cause w page F-151
5
Check for poor connection of following parts
Yes Repair or replace
. Ignition coil
l Igniter l Distributor
-- l High-tension lead
No l Injector Go to next step l Circuit opening relay l ECU
F-54
TROUBLESHOOTING GUIDE
16 ENGINE STALLS SUDDENLY (INTERMITTENT)
DESCRIP- l Engine intermittently stops running
TION l Before stalling, engine condition OK [TROUBLESHOOTING HINTS]
@ Intermittently no spark or no-fuel injection caused by ve-
hicle vibration, acceleration, or deceleration
*Poor connection in wire harness
3 INSPECTION
Check if “00” is displayed on Self-Diagnosis
Checker with ignition switch ON c7 page F-82
g
-%ELECT SW: A
Check for poor connection of following parts l ignition coil
l igniter l Distributor l High-tension lead l lniector
l Ci;cuit opening relay l ECU
Check if ECU terminal voltages are OK
MTX...Especially lB, 2A, 28 and 2C
ATX... Especially lB, 3A, 38 and 3C w page F-150
Note
l When checking voltages, tap, move, and
wiggle harness and connector to recreate
problem
Yes
No Service Code No. displayed
Check for cause (Refer to specified
check sequence) Note
l When checking wiring harness and
connectors, tap, move, and wiggle
suspect sensor and/or harness to
recreate problem
“88” flashes
Check ECU terminal IF voltage w page F-150
Specification: Battery voltage
(Ignition switch ON)
c3 If OK, replace ECU CT= page F-149
+ If not OK, check wiring between
ECU and Self-Diagnosis Checker
Yes
Repair or replace
No Go to next step
Yes
No
T ACTION
Go to next step w page F-83
Go to Troubleshooting No.2
‘CRANKS NORMALLY BUT WILL NOT
START (NO COMBUSTION)” CT- page F-30
Check for cause D page F-151
F-56
F SELF-DIAGNOSIS FUNCTION
Troubleshooting
If a service code number is show on the SST, check for the cause by using the chart related to the code
number shown.
r c :ODE No. -
iTEl
I 02 (DISTRIBUTOR Ne-SIGNAL)
INSPECTION I
ACTION
1
1
2
Check if Code No.03 is also present
-5- Check terminal-wire for continuity
4
Check if battery voltage exists at distributor
terminal-wire
-i-- Check terminal-wire between distributor and
ECU terminal 2E (MTX) 2A (ATX) for continuity
and ground
6
Cl$c; ,if$CU terminal 2E (MTX) 2A (ATX) volt- Yes Replace ECU
w page F-149
w page F-152 . No
Go to next step
7
I I
Check if OV or 45V--55V exists at distributor 1 Yes 1 Reolace distributor I
8
- Check distributor circuit for poor connection Yes
1 I Repair or replace connector
I
No SOHC
Go to Step 3
DOHC
Go to next step
Yes Go to next step I
No Go to Step 5
Yes
I I Go to next step
I
No
I I
Repair or replace
Yes Go to next step
No Check for open circuit in wiring from
distributor to main relay (FUEL INJ
relay)
Yes Go to next step
No Repair or replace
terminal-wire (W)
No Go to next step
Check if 4.5V-5.5V exists at ECU terminal 2E
(MTX) 2A (ATX) (With distributor connector dis-
connected) Yes Check for short circuit in wiring from
distributor to ECU
No Replace ECU CT page F-149
.-I 4
F-86
F SELF-DIAGNOSIS FUNCTION
r C :ODE No.
03 (DISTRIBUTOR G-SIGNAL) - DOHC ¶
El
i- I
INSPECTION
Check distributor circuit for poor connection ACTION
Yes Repair or replace connector
1
2
-s-
-T-
--c
--if-
7
-ii- No
I I Go to next step
Check if Code No.02 is also present Yes
I I Go to next step
Check terminal-wire for continuity No Go to Step 5
Yes Go to next step
Check if battery voltage exists at distributor
terminal-wire No Repair of replace
Yes Go to next step
No
I I
Check for open circuit in wiring from
distributor to main relay
Check terminal-wire between distributor and
Yes Go to next step
ECU terminal 2G (MTX) 2J (ATX) for continuity
and ground
No Repair or replace
Ct$; if$CU terminal 2G (MTX) 2J (ATX) volt- Yes Replace ECU r=+ page
F-149 CT page
F-154 No
Go to next step
Check if OV or 4.5V--53 exists at distributor Yes
I I Replace distributor
terminal-wire
No
I I Go to next step
I Check if 4.5V--5.5V exists at ECU terminal 2G
(MTX) 2J (ATX) (With distributor connector dis-
connected) Yes Check for short circuit in wiring from
distributor to ECU
No Replace ECU CT page
F-149
I I 23UOFX-0: i5
F-88