1992 MAZDA PROTEGE engine

TROUBLESHOOTING GUIDE F
REAR SEAT C
03UOFX-01
9MUOF2-1;
PRECAUTION
Fuel Pressure Release and Servicing Fuel System
Fuel in the fuel system remains under high pressure even when
the engine is not running.
a) Before disconnecting any fuel line, release the fuel pres-
sure from the fuel system to reduce the possibility of injury
or fire.
1. Start the engine.
2. Push the rear seat cushion buttons and remove the
cushion.
3. Disconnect the fuel pump connector.
4. After the engine stalls, turn off the ignition switch.
5. Reconnect fuel pump connector and install the rear seat
cushion.
b) Use a rag as protection from fuel spray when disconnect-
ing the hoses.
Plug the hoses after removal.
c) When inspecting the fuel system, use a suitable fuel pres-
sure gauge.
Caution
l Install hose clamps to secure the fuel pressure
gauge to the fuel filter and the fuel main hose to pre-
vent fuel leakage.
Pinching Hose
When pinching an air hose or a fuel hose with pliers, wrap
the hose with a rag to prevent damage.
03UOFX-016
F-29

F TROUBLESHOOTING GUIDE
SYMPTOM TROUBLESHOOTING
2 CRANKS NORMALLY BUT WILL NOT START (NO COMBUSTION)
l Engine cranks at normal speed but shows no sign of “firing”
DESCRIP-
*Battery in normal condition
TION
*Throttle valve not held fully open while cranking (Dechoke system not operate)
*Fuel in tank [TROUBLESHOOTING HINTS]
Because of no combustion, possibly no fuel is injected to engine or no ignition at all cylinders
:I) No spark
@I Low fuel line pressure
l Ignition control malfunction
@ Low engine compression l Ignition system component malfunction
3 No fuel injection
l Fuel pump inoperative l Injectors inoperative
TEP INSPECTION
ACTION
1 Check if strong blue spark is visible at discon-
Yes Go to Step 3
netted high-tension lead
No Go to Step 2
2 Check if “00” is displayed on Self-Diagnosis
Yes Check ignition system (Refer to
Checker with ignition switch ON
Troubleshooting “Misfire”) w page G-5
w page F-82
No Service Code No. displayed
Check for cause (Refer to specified
check sequence) w page F-83
“88” flashes
Check ECU terminal 1F voltage w page F-150
Specification: Battery voltage
(Ignition switch ON)
W: SELF TEST e If OK, replace ECU w page F-149 c3 If not OK, check wiring between
SELECT SW: A ECU and Self-Diagnosis Checker
3 Connect diagnosis connector terminals F/P and
Yes Check if engine starts in this condition
GND with jumper wire and check for fuel pump
operating sound with ignition switch ON c3 If starts, check circuit opening relay c7 page F-129
w page F-125
c3 If does not start, go to Step 5
DIAGNOSIS C
Go to next step ._-,
._. ,
F-30

F TROUBLESHOOTING GUIDE
3 CRANKS NORMALLY BUT WILL NOT START (PARTIAL COMBUSTION) - WHEN ENGINE COLD
DESCRIP- *Engine cranks at normal speed but shows only partial combustion and will not continue to run
TION
l Battery in normal condition
*Fuel in tank
[TROUBLESHOOTING HINTS]
0 Air/Fuel mixture too rich
*Air cleaner element clogged
l Airflow meter stuck @ Low engine compression
@ Air/Fuel mixture too lean
l Fuel injection control malfunction
(Correction for coolant temperature)
*Low fuel line pressure
*Air leakage of intake air system
Checker with ignition switch ON
CT page F-83
w page F-150
Specification: Battery voltage
(Ignition switch ON)
W: SELF TEST w page F-149
Fuel line pressure:
285-314 kPa (2.7-3.2 kg/cm’, 38-48 psi) If fuel line pressure quickly in-
creases, check pressure regulator CF- page F-129
d If fuel line pressure gradually in-
creases check for clogging be-
I pump and pressure
Check if fuel return hose is clogged or
F-32

TROUBLESHOOTING GUIDE
TEP INSPECTION ACTION
4 Check if ECU terminal voltages are OK Yes Go to next step
MTX...Especially IC, 20 and 2Q
ATX... Especially lC, 2E and 3D v page F-150
No Check for cause ~3‘ page F-151
5
Check for air leakage of intake air system com- Yes Repair or replace
ponents
No Go to next step
6 Check if engine starts when water thermosensor Yes Check water thermosensor c7 page F-158 is disconnected
Check for correct engine compression 82-10 ’ No
Check engine condition CIP page Bl-10
Engine compression: 82-10
l BP SOHC l Worn piston, piston rings or cylinder 834 kPa (8.5 kg/cm*, 121 psi)300 rpm
wall
l BP DOHC l Defective cylinder head gasket 883 kPa (9.0 kg/cm*, 128 psi)-300 rpm l Distorted cylinder head
l B8 l Improper valve seating 932 kPa (9.5 kg/cm*, 135 psi)300 rpm *Valve sticking in guide
9 Check if spark plugs are OK Yes Go to next step CT- page G-18
1.0-l .l mm
(0.039-0.043 in) DAMAGE AND
DETERIORATION No Clean, or replace c7 page G-18
10 Try known good ECU and check if condition
improves CT- page F-149
23UOFX-01 I
F-33

F TROUBLESHOOTING GUIDE
4
CRANKS NORMALLY BUT WILL NOT START (PARTIAL COMBUSTION) - AFTER WARM-UP *Engine cranks at normal speed and shows partial combustion but will not continue to run after running and
DESCRIP- hot soaked
TION *Battery in normal condition
*Engine starts normally when cold
[TROUBLESHOOTING HINTS] 3 Air/Fuel mixture too rich
@ Vapor lock
l Insufficient fuel injection control
*Fuel pressure not held in fuel line after engine stopped
(Correction for coolant temperature)
*High RVP (winter) fuel used in warm weather
l Injector fuel leakage @ Pressure regulator control system malfunction [BP]
switch ON, then check if en
D‘ page F-134
Fuel line pressure:
265-314 kPa (2.7-3.2 kg/cm’, 36-46 psi) ne pressure w
+ If fuel line pressure quickly in-
if fuel return hose is clogged
or
F-=34

F TROUBLESHOOTING GUIDE
5
CRANKS NORMALLY BUT HARD TO START - ALWAYS
DESCRIP- l Engine cranks at normal speed but requires excessive cranking time before starting
TION l Battery in normal condition
*Engine runs normally at idle [If idle condition not OK, refer to “Rough idle” (Nos. 8-12)J [TROUBLESHOOTING HINTS]
@ Air/Fuel mixture too lean
@ Air/Fuel mixture too rich l Fuel injection control malfunction
(Correction for coolant temperature) *Air cleaner element clogged
l Airflow meter stuck
*Low fuel line pressure
l Air leakage @ Poor ignition spark
;TEP INSPECTION ACTION
1
Check if “00” is displayed on Self-Diagnosis Yes Go to next step
Checker with ignition switch ON 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
Check ECU terminal 1F voltage w page F-150
Specification: Battery voltage
(Ignitlon switch ON)
* If OK, replace ECU w page F-149
W: SELF TEST c3 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
VsCUUm: More than 450 mmHg (17.7 inHg) No Check for air leakage of intake air sys-
tem components
3 Check if air cleaner element is clean
Yes Go to next step w page F-79
No
Replace air cleaner element
4 Check if engine starts easily when throttle valve Yes Check throttle valve for carbon deposit
quarter open and then go to Step 6 Fuel line pressure:
265-314 kPa (2.7-3.2 kg/cm*, 38-46 psi)
(Vacuum hose to pressure regulator dis-
pressure while pinching
c3 If fuel line pressure quickly in-
creases, check pressure regulator w page F-129
c3 If fuel line pressure gradually in-
creases, check for clogging be-
tween fuel pump and pressure
If not clogged, check fuel pump
maximum pressure W- page F-126
F-36

F TROUBLESHOOTING GUIDE
6 CRANKS NORMALLY BUT HARD TO START - WHEN ENGINE COLD
l Engine cranks at normal speed but requires excessive cranking time before starting )ESCRIP-
l Battery in normal condition UON
*Restarts OK after warm-up
*Engine runs normally at idle [If idle condition is not OK, refer to “Rough idle” (NOS. 8-124 [TROUBLESHOOTING HINTS]
3 Air/Fuel mixture too rich
@ Air/Fuel mixture too lean l Airflow meter sticking l Fuel injection control malfunction
*Air cleaner element clogged
(Correction for coolant temperature)
l Idle speed control malfunction
@ Poor atomization
*Low RVP (summer) fuel is used in cold weather
SYSTEM SELECT: 1
Check ECU terminal 1 F voltage CT- page F-150
Specification: Battery voltage
(Ignition switch ON)
c3 If OK, replace ECU CT page F-149 c3 If not OK, check wiring between
ECU and Self-Diagnosis Checker Vacuum: More than 450 mmHg (17.7 inHg)
.
No
Check for air leakage of intake air sys-
tem components
5 Check if air cleaner element is clean Yes
Go to next step
~7 page F-79
No
Replace air cleaner element
6 Disconnect ISC valve connector at idle and
Yes Go to next step
check if engine speed increases CT page F-l 16
No
Replace ISC valve CT page F-109
--’
F-38

F TROUBLESHOOTING GUIDE
7 CRANKS NORMALLY BUT HARD TO START - AFTER WARM-UP
*Engine cranks at normal speed but requires excessive cranking time before starting after running and hot
DESCRIP- soaked
TION *Battery in normal condition
*Engine starts normally when cold
*Engine runs normally at idle [If idle condition not OK, refer to “Rough idle” (Nos. 8-12)] [TROUBLESHOOTING HINTS]
3 Air/Fuel mixture too rich
@ Vapor lock l Fuel injection control malfunction
*Fuel pressure not held in fuel line after engine stopped l Injector fuel leakage
*High RVP (winter) fuel used in warm weather
l Pressure regulator control system malfunction [BP] w page F-150
Specification: Battery voltage
(Ignition switch ON)
W: SELF TEST c3 If OK, replace ECU w page F-149 * If not OK, check wiring between CT- page F-134
Fuel line pressure: More than 147 kPa
(1.5 kg/cm*, 21 psi) for 5 min. w page F-130
+ If OK, replace pressure regulator CT- page F-130
c3 If not OK, check fuel pump hold w page F-125
If fuel pump is OK, check injectors
for fuel leakage (3 page F-132
F-40