1992 MAZDA PROTEGE ecu wiring

. .-
CAUTION Gl
CAUTION WITH ELECTRICAL PARTS
Battery Cable
Before disconnecting connectors or replacing electrical parts,
disconnect the negative battery cable.
SMUGIX-022
YMUGIX-023
SMUGIX-02
SMUGIX-02
03UGIX-011 Connectors
Removal of connector
Never pull on the wiring harness when disconnecting con-
nectors.
Connectors can be removed by pressing or pulling the lock
lever as shown.
Locking of connector
When locking connectors, make sure to listen for a click that
will indicate they are securely locked.
Inspection
1. When a tester is used to check for continuity or to measure
voltage, insert the tester probe from the wire harness side.
GM 3

F
FUEL AND EMISSION
CONTROL SYSTEM
INDEX ...........................................
OUTLINE ...................................... ;: 2
SYSTEM DIAGRAM ...................... F-
:
VACUUM HOSE ROUTING
DIAGRAM .................................
WIRING DIAGRAM ....................... F- 6
- 7
ENGINE CONTROL UNIT (ATX) ...... F- 13
SPECIFICATIONS.. ....................... F- 15
COMPONENT DESCRIPTIONS.
...... F- 16
TROUBLESHOOTING GUIDE.. ......... F- 20
ENGINE CONTROL OPERATION
CHART
..................................... F- 20
RELATIONSHIP CHART.. .............. F- 24
USING THIS SECTION .................. F- 25
DIAGNOSTIC INDEX .................... F- 27
PRECAUTION ............................. F- 29
SYMPTOM TROUBLESHOOTING .... F- 30
ENGINE TUNE-UP
.......................... F- 76
PREPARATION ............................
F- 76
BASIC INSPECTION ..................... F- 78
ADJUSTMENT .............................
F- 79
SELF-DIAGNOSIS FUNCTION .......... F- 82
DESCRIPTION .............................
F- 82
PREPARATION
............................
F- 83
SERVISE CODE NUMBER.. ........... F- 83
SWITCH MONITOR FUNCTION ...... F-105
INTAKE AIR SYSTEM.. ................... F-109
COMPONENT PARTS.. ................. F-109
THROTTLE BODY ........................ F-l 12
DYNAMIC CHAMBER ................... F-l 12
INTAKE MANIFOLD ..................... F-l 13
ACCELERATOR PEDAL ................ F-l 14
ACCELERATOR CABLE ................ F-l 14
IDLE SPEED CONTROL (ISC)
SYSTEM ......................................
F-115
DESCRIPTION ............................. F-115
PREPARATION
............................ F-116
SYSTEM OPERATION.. ................. F-l 16
ISC VALVE ................................. F-116
AIR VALVE
................................. F-116
VARIABLE INERTIA CHARGING
SYSTEM (VICS) [DOHC] ................ F-l 17
DESCRIPTION ............................. F-117
SYSTEM OPERATION ................... F-l 18
SHUTTER VALVE ACTUATOR.. ...... F-l 18
SOLENOID VALVE (VICS). ............. F-118
VACUUM CHAMBER.. .................. F-119
FUELSYSTEM .............................. F-l 20
DESCRIPTION
............................. F-l 20
PRECAUTION ............................. F-121
SYSTEM OPERATION.. ................. F-121
FUEL TANK ................................
F-l 23
FUEL FILTER .............................. F-l 24 FUEL PUMP ............................... F-l 25
CIRCUIT OPENING RELAY.. .......... F-129
PRESSURE REGULATOR.. ............ F-129
INJECTOR .................................. F-l 31
PRESSURE REGULATOR
CONTROL SYSTEM.. .................... F-l 34
SOLENOID VALVE (PRESSURE
REGULATOR CONTROL). ............ F-l 35
EXHAUST SYSTEM ........................ F-l 36
COMPONENT PARTS.. ................. F-136
OUTLINE OF EMISSION
CONTROL SYSTEM.. .................... F-l 37
STRUCTURAL VIEW.. ................... F-l 37
POSITIVE CRANKCASE
VENTILATION (PCV) SYSTEM.. ..... F-138
DESCRIPTION .............................
F-l 38
PCV VALVE ................................ F-l 38
EVAPORATIVE EMISSION
CONTROL SYSTEM.. .................... F-l 39
DESCRIPTION ............................. F-l 39
SYSTEM OPERATION.. ................. F-140
SOLENOID VALVE
(PURGE CONTROL) ................... F-140
SEPARATOR ............................... F-l 40
CHECK VALVE (TWO-WAY) ........... F-140
CHECK-AND-CUT VALVE.. ............ F-141
CHARCOAL CANISTER.. ............... F-141
DECELERATION CONTROL
SYSTEM ...................................... F-l 42
DESCRIPTION ............................. F-l 42
DASHPOT .................................. F-142
FUEL CUT CONTROL SYSTEM ....... F-143
DESCRIPTION ............................. F-l 43
PREPARATION ............................ F-l 43
SYSTEM OPERATION.. ................. F-143
DECHOKE CONTROL SYSTEM.. ...... F-145
DESCRIPTION ............................. F-l 45
SYSTEM OPERATION ................... F-l 45
CONTROL SYSTEM ....................... F-l 47
PREPARATION ............................ F-147
STRUCTURAL VIEW.. ................... F-l 48
ENGINE CONTROL UNIT (ECU) ..... F-149
AIRFLOW METER (WITH INTAKE AIR
THERMOSENSOR) ..................... F-168
WATER THERMOSENSOR.. ........... F-168
THROTTLE SENSOR .................... F-l 69
OXYGEN SENSOR.. ..................... F-171
MAIN RELAY (FUEL INJ RELAY) .... F-172
CLUTCH SWITCH (MTX) ............... F-172
NEUTRAL SWITCH (MTX). ............. F-173
POWER STEERING PRESSURE
SWITCH .................................... F-173
WJOFX-001

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

TROUBLESHOOTING GUIDE F
TEPt INSPECTION ACTION
Fuel line pressure:
More than 147 kPa (1.5 kg/cm*, 21 psi)
w page F-125
4 If OK, check injector for fuel
w page F-132
w page F-127
w page F-158
+ If OK check connections of water
osensor and ECU 2Q terminal
check connections of water
osensor and ECU 2E terminal
K, replace water ther-
w page F-83
w page F-150
Specification: Battery voltage
(Ignition switch ON)
Q If OK, replace ECU CT page F-149
+ If not OK, check wiring between
ECU and Self-Diagnosis Checker
23UOFX-0:
F-35

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

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