1992 MAZDA PROTEGE F 149

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

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

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

TROUBLESHOOTING GUIDE F
12 ROUGH IDLE/ENGINE STALLS JUST AFTER STARTING
DESCRIP-
*Engine starts normally but vibrates excessively or stalls just after starting (acceleration from idle) TION
*Idle conditions are normal in the other conditions [TROUBLESHOOTING HINTS]
@ Fuel injection control system or idle speed control sys-
@ Idle speed misadjustment
tern malfunction @ Ignition timing misadjustment
*Start signal not input to ECU iTEl
-s-- 3
4
5 INSPECTION
-T- ACTION
Check if “00” is displayed on Self-Diagnosis
Checker with ignition switch ON w page F-82
SYSTEM,SELECT: I
r -SELECT SW: A
Check if ECU terminal voltages are OK
MTX...Especially 1 N
ATX... Especially 1T w page F-150
Connect System Selector to diagnosis connector
and set Test Switch to “SELF TEST” and check
for correct ignition timing at idle after warm-up w page F-78
Ignition timing (BTDC)
l BP DOHC : 9”-11 o l BP SOHC : 4O--6O
l B8 : 60-80
Check continuity between throttle sensor termi-
nals IDL and E CT page F-159
MTX
Clearance between throttle
lever and stopper
MTX O.lmm (0.004 in)
1 .Omm (0.039 in)
ATX 0.1 mm (0.004 in)
0.6mm (0.024 in) Continuity
Yes
No
Yes
No
Try known good ECU and check if condition
mproves w page F-149 Yes
No
Yes
Go to next step No
Check for cause Yes
In same condition as Step 3 inspection
and apply parking brake
Check for correct idle speed w page F-80
Idle speed: 700-800 rpm
No
Adjust Yes
Go to next step No
Adjust Go to next step Service Code No. displayed
Check for cause (Refer to specified
check sequence) w page F-83
“88” flashes
Check ECU terminal IF voltage w page F-150
Specification: Battery voltage
(Ignition switch ON)
d If OK, replace ECU w page F-149
* If not OK, check wiring between
ECU and Self-Diagnosis Checker c7 page F-151
3 If OK, go to next step
3 If not OK, adjust idle speed w page F-80
w page F-79
w page F-159
F-49

F TROUBLESHOOTING GUIDE
13 HIGH IDLE SPEED AFTER WARM-UP
DESCRIP- l Idle speed excessive after warm-up
TION [TROUBLESHOOTING HINTS]
Excessive intake air supplied to engine
@I Throttle valve not fully closed
@ Idle speed control malfunction
l Air valve not closed l ISC valve stuck
l ISC valve connector disconnected l A/C, P/S, or E/L signal sent to ECU l Incorrect coolant temperature signal
stalled and operates freely w page F-l 14
@ If OK, go to Step 2
+ If not OK, clean, adjust or replace w page F-l 14
* If contaminated, clean throttle body Dashpot set speed: + If not contaminated, replace throttle
..*.............*..,........,... Approx. 3,000 rpm w page F-109
BP SOHC . . . . . . . . . . . . . . . . . . . . . . Approx. 2,700 rpm
BP DOHC . . . . . . . . . . . . . . . . . . . . . . Approx. 3,500 rpm
w page F-83
Check ECU terminal 1F voltage w page F-150
Specification: Battery voltage
(Ignition switch ON)
e If OK, replace ECU w page F-149
c3 If not OK, check wiring between
ECU and Self-Diagnosis Checker
Check for cause (Refer to specified
check sequence) w page F-108
W: SELF TEST
and Self-Diagnosis Checker
F-50

TROUBLESHOOTING GUIDE F
iTEP INSPECTION ACTION
6 Connect System Selector to diagnosis connector Yes Go to next step
and set Test Switch to “SELF TEST” when en-
gine is cold
Check if engine speed decreases as engine
warms up
w page F-l 16
No Check air valve w page F-116
7
Disconnect ISC valve connector at idle and Yes Go to next step
check if idle speed increases
CT page F-l 16
No
Check ISC valve CT page F-l 16
8
Pinch PCV hose with pliers and check if engine Yes Check PCV valve
speed decreases w page F-136
Go to next step
9 Check if ECU terminal voltages are OK
Yes Try known good ECU and check if con-
MTX...Especially 20, 20 and 2Q
dition improves
ATX... Especially 28, 2E and 3D CT page F-149
CT page F-152 No Check for cause w page F-153
23UOFX-079
F-51

F TROUBLESHOOTING GUIDE
14 IDLE MOVES UP AND DOWN/IDLE HUNTING
DESCRIP-
*Engine speeds up and down periodically at idle
TION
[TROUBLESHOOTING HINTS]
@ idle switch (built in throttle sensor) OFF at idle
@ Air leakage
@ Fuel injection amount inconstant
spoor contact point inside airflow meter
@ Poor ignition
iTEP INSPECTION
1 Check if “00” is displayed on Self-Diagnosis
Checker with ignition switch ON
CT page F-82
SYSTEM SELECT: 1
ACTION
Yes Go to next step
No
Service Code No. displayed
Check for cause (Refer to specified
check sequence) w page F-83
“88” flashes
,,;9 Check ECU terminal 1F voltage w page F-150
Specification: Battery voltage
(Ignition switch ON)
W: SELF TEST + If OK, replace ECU KIT page F-149
ELECT SW: A + If not OK, check wiring between
ECU and Self-Diagnosis Checker
2 Check for correct intake manifold vacuum at idle Yes Go to next step
Intake manifold vacuum:
More than 450 mmHg (17.7 inHg)
No Low vacuum
Check for air leakage at intake air
system
3 Check if air cleaner element is clean Yes Go to next step
w page F-79
No Replace air cleaner element
4
Disconnect high-tension lead at idle and check if Yes Go to next step
engine speed decreases equally at each cylinder
No Go to Step 9
5 Check if ECU terminal voltages are OK Yes Go to next step
w page F-150
No Check for cause KII page F-151
6
Connect System Selector to diagnosis connector Yes Go to next step
and set Test Switch to “SELF TEST” and check
for correct ignition timing at idle after warm-up
w page F-79
Ignition timing (BTDC)
l BP DOHC : 9”-11 o l BP SOHC : 4O-8” l B6 : 6O--8O No Adjust ignition timing r-7 page F-79
TEST SWITCH . .
F-52

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