1992 MAZDA PROTEGE engine

TROUBLESHOOTING GUIDE
iTEP INSPECTION ACTION
5 Warm-up engine to normal operating tempera-
Yes Change fuel to another brand
ture and stop it
Connect diagnosis connector terminals F/P and
GND with jumper wire for 3 minutes with ignition
switch ON, then check if engine starts easily
DIAGNOSIS CONNECTOR No
Go to next step
G
F/P 6
Try known good ECU and check if condition
Yes Replace ECU w page F-149 improves w page F-149 No
Change fuel to another brand
23UOFX-02:
F-41

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
WEAR AND CA
DAMAGE AND
DETERIORATION
r;f> If OK, replace injector
=D If not OK, check for cause w page F-131
u page Bl-10
82-l 0
Fuel line pressure:
265-314 kPa (2.7-3.2 kg/cm2, 38-48 psi) fuel line pressure while pinching
* If fuel line pressure quickly in-
creases, check pressure regulator L-Y page F-129
~3 If fuel line pressure gradually in-
creases, check for clogging be-
tween fuel pump and pressure
maximum pressure
CT page F-126
airflow meter moves smoot
_, .’
No Go to next step
I1
Check for correct engine compression
Yes Go to next step
CI page 81-10
82-l 0
Engine compression (Minimum):
l BP SOHC
834 kPa (8.5 kg/cm*, 121 psi)300 rpm
l BP DOHC
883 kPa (9.0 kg/cm*, 128 psi)-300 rpm
l B6 No Check for cause
CT page 81-10
82-l 0
932 kPa (9.5 kg/cm*, 135 psi)-300 rpm
I2 Connect System Selector to diagnosis connector
Yes Try known good ECU and check if con-
and set Test Switch to “SELF TEST” and check
dition improves
CT page F-149
for correct ignition timing at idle after warm-up
CT page F-79
Ignition timing (BTDC)
BP DOHC : Q”-ll”
BP SOHC : 4O-6O
B6
: 6”--8* No Adjust ignition timing
a- page F-79
23UOFX-Oi
F-43

F TROUBLESHOOTING GUIDE
9
ROUGH IDLE/ENGINE STALLS AT IDLE - BEFORE WARM-UP
DESCRIP-
*Engine speed low or engine stalls or vibrates excessively at idle during warm-up
TION
[TROUBLESHOOTING HINTS]
@ Low intake air amount
@ Low fuel injection control
l Airflow meter stuck
*Fuel injection control malfunction
*Air cleaner element clogged
(Correction for coolant temperature)
*Air valve
@ Poor atomization
*Low RVP (summer) fuel used in cold weather
w page F-83
W: SELF TEST Check ECU terminal 1F voltage
w page F-150
Specification: Battery voltage
(Ignition switch ON)
c3 If OK, replace ECU c3 page F-149
* If not OK, check wiring between
ECU and Self-Diagnosis Checker
Vacuum: More than 450 mmHg (17.7 inHg)
AX.. Especially 2B, 2E and 30
w page F-150
NO Check for cause CT page F-181
5 Disconnect ISC valve connector and check if en-
Yes Go to next step
gine speed increases after warm-up
CT page F-l 18
No Replace ISC valve c3 page F-109
F-44

TROUBLESHOOTING GUIDE F
s TEP INSPECTION ACTION
6 Check for correct water thermosensor resistance
Yes Go to next step
w page F-158
RESISTANCE
WI
20
‘70
I No Replace water thermosensor w page F-158
A.7
0.5
lE 41
(1400,
(1%) COOLANT TEMPERATURE OC (OF)
Connect System Selector to diagnosis connector
Check if engine speed decreases as engine
Ignition timing (BTDC)
l BP DOHC : go-11 * l BP SOHC : 4*-6O
23UOFX-OS
F-45

F TROUBLESHOOTING GUIDE
10
ROUGH IDLE/ENGINE STALLS AT IDLE - AFTER WARM-UP
DESCRIP-
rlON
*Engine runs normally at idle during warm-up but engine stalls or vibrates excessively after warm-up [TROUBLESHOOTING HINTS]
3 Idle speed control system malfunction @ Air/Fuel mixture too rich
3 Air/Fuel mixture too lean l Fuel injection control malfunction l Air leakage (Correction for coolant temperature)
*Low fuel line pressure @ Poor ignition
@ Low engine compression CT= page F-83
Check ECU terminal 1F voltage CT page F-150
Specification: Battery voltage
(Ignition switch ON)
* If OK, replace ECU w page F-149 * If not OK, check wiring between
ECU and Self-Diagnosis Checker
Check for cause LY page F-151
Vacuum: More than 450 mmHg (17.7 inHg)
I.:.F page F-109
F-46

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

F TROUBLESHOOTING GUIDE
11 ROUGH IDLE/ENGINE STALLS AT IDLE - WHEN A/C, P/S, OR E/L ON
DESCRIP.
*Engine stalls or vibrates excessively at idle when A/C, P/S, or E/L ON TION *A/C, P/S, daytime running lights (Canada), headlights, blower fan and electric cooling fan operate normally
*Idle condition is normal when A/C, P/S, and E/L is OFF (TROUBLESHOOTING HINTS]
@ Idle speed control system malfunction l Engine speed feedback control inoperative ;TEP INSPECTION
ACTION
1
Check if “00” is displayed on Self-Diagnosis Yes
Checker with ignition switch ON Go to next step W page F-82 No
Service Code No. displayed
Check for cause (Refer to specified
SYSTEM SELECT: 1 check sequence) w page F-83
“88” flashes
W:SELFTEST
Check ECU terminal 1 F voltage w page F-150
Specification: Battery voltage
(Ignition switch ON)
* If OK, replace ECU w page F-149
c3 If not OK, check wiring between
ECU and Self-Diagnosis Checker
2 Check switches for correct operation by Self-
Yes
Diagnosis Checker Monitor Lamp with ignition Go to next step
switch ON CT page F-105
No Lamp not ON or OFF with specltied
switch
Check for cause (Refer to specified
check sequence) w page F-108
Lamp always ON
Check wiring between ECU terminal ID
and Self-Diagnosis Checker
W:SELFTEST
3
EhFKk if ECU terminal IK (MTX) II (ATX) voltage
Yes Try known good ECU and check if con-
dition improves w page F-150 w page F-149
Specification: Battery voltage (at Idle)
1 K (LGIY)
No
Check for short circuit in wiring be-
tween diagnosis connector terminal
TEN and ground
23UOFX-02
-’
F-48