1987 MAZDA 626 Workshop Manual

4A CONTROL SYSTEM
Terminal
(Wire color) Connected to Condition Voltage

I
(LgB)
Idle switch Idle switch
ON
Below 1.5 V I
(LgB)
Idle switch
Idle switch OFF Battery voltage
J
— —
76G04A-174
( I
G
X
C
0
X
H F D B

F6 Engine (Singapore)
Terminal
(Wire color) Connected to Condition Voltage

A
— — —

B
(YL) Ignition coil Ignition switch
ON
and engine running Battery voltage
C
(B)
Ground
— —

D
(GB) Relay Engine speed below approx. 2,100
rpm
Below 1,5V D
(GB) Relay
Engine speed above approx. 2,100
rpm
Battery voltage
F
(BW) Ignition switch Ignition switch
ON
Battery voltage

76G04A-175
4A—92

CONTROL SYSTEM 4 A
76G04A-176
76G04A-177
76G04A-178
Replacement
1. Disconnect the negative battery cable.
2. Remove the front console covers (right or left).
3. Disconnect the connectors from the control unit.
4. Remove and replace the control unit.
INHIBITOR SWITCH
Inspection
1. Verify that the starter operates with the ignition
switch at START position in
P
and N positions only.
2. Check that the back-up lights illuminate when R
position selected and the ignition switch is ON.
3. If not as specified, check the following:
(1) Jack up the vehicle and support it with safety
stands.
(2) Disconnect the inhibitor switch connector.
(3) Check continuity of the switch with an
ohmmeter.
Connecting guide

Position

N

D,1,2
Connector terminal

O -O
O
O
-O
-O

O—O: indicates continuity

4. Replace if necessary.
IDLE SWITCH
Inspection
1. Warm up the engine and run it at idle.
2. Turn all accessories OFF.
3. Connect a tachometer to the engine.
4. Connect a voltmeter to the carburetor connector
F terminal.
76G04A-179
4A-93

4A CONTROL SYSTEM
Idle switch
Adjust screw
76G04A-180
76G04A-181
5. Increase the engine speed to more than 2,000 rpm
and decelerate gradually.
6. Check the voltage.

Specification
Engine speed
^^^

FE 8Valve—
Unleaded Fuel
& F6 Sin-
gapore
Others
At idle below 1,5V Battery voltage
Above 1,000—1,100 rpm Battery voltage below 1.5V

7. If the voltage is not within specification, turn the ad-
just screw to adjust.
VACUUM SWITCH
On-Vehicle Inspection
1. Run the engine at idle.
2. Connect a voltmeter to the vacuum switch connec-
tor terminal wire (LB).
Voltage: Approx. 12V
3. Disconnect the vacuum hose from the vacuum
switch, and plug it.
4. Check the voltage.
Voltage: Less than 1.5V
Off-Vehicle Inspection
Inspection
1. Remove the vacuum switch.
2. Connect a vacuum pump to the vacuum switch.
3. Connect an ohmmeterto the vacuum switch, and
check the continuity between the switch terminals.

Vacuum Continuity
MTX: More than 300 mmHg (11.8 inHg) No ATX: More than 200 mmHg (7.9 inHg) No
Others Yes

76G04A-182
4A—94

CONTROL SYSTEM 4A
WATER THERMO SWITCH (RADIATOR)
Inspection
1. Remove the switch from the radiator.
2. Place the switch in water with a thermometer and
gradually heat the water.
3. Check for continuity of the switch with an
ohmmeter.

Coolant temp. Continuity
More than approx.
17°C (63°F)
Yes
Less than approx.
17°C (63°F)
No

76G04A-183
4. If not as specified, replace the water thermo switch.
Note
a) Apply sealing tape to the threads of the
switch before installing it.
b) After installation, check the coolant level
and check for leaks.
76g04a-184
WATER THERMO SWITCH (INTAKE MANIFOLD)
Inspection
1. Remove the switch from the intake manifold.
2. Place the switch in water with a thermometer and
gradually heat the water.
3. Check for continuity of the switch with an
ohmmeter.

Coolant temp. Continuity
More than approx.
72°C (162°F)
Yes
Less than approx.
72°C (162°F)
No

76G04A-185 4. If not as specified, replace the water thermo switch.
Note
a) Apply sealing tape to the threads of the
switch before installing it.

b)
After installation, check the coolant level
and check for leaks.
76G04A-186
4A-95

4A EXHAUST SYSTEM
EXHAUST SYSTEM
EXCEPT FE 8VALVE—UNLEADED FUEL
Removal and Installation
1. Remove in the sequence shown in the figure.
2. Install in the reverse order of removal.
Torque specifications
1. Center silencer and main silencer
2. Brackets
76G04A-187
3. Front silencers
4. Exhaust manifolds
Inspection
Visually check the exhaust system for cracks or
damage.
4A—96

EXHAUST SYSTEM 4A
FE 8 VALVE-UNLEADED FUEL
Removal and Inspection
1. Remove in the sequence shown in the figure
2. Install in the reverse order of removal.
Torque Specifications

L

22—28 N-m (2.2—2.9 m-kg, 16—21 ft-lb)
34—49 N-m (3.5—5.0 m-kg, 26—36 ft-lb)
55—60 N-m (5.6—8.2 m-kg, 40—59 ft-lb)
.8—11 Nm .8—1.1 m-kg, 69—95 in-lb)
N-m 3 m-kg, 25—38 ft-lb)
76G04A-189
1. Main silencer
2. Middle pipe
3. Pre-silencer
4. Catalytic converter
5. Bracket
6. Front pipe
Inspection
1. Check the catalytic converter and exhaust pipe for
deterioration or restriction.
2. Check the insulation covers welded onto the cata-
lytic converter for damage.
Note
If the insulation cover is touching the catalytic
converter housing, excessive heat at the floor
will occur.
76G04A-190
4A-97

FUEL AND EMISSION
CONTROL SYSTEMS
(FUEL INJECTION FE)
OUTLINE 4B— 2
SYSTEM DIAGRAM 4B— 2
COMPONENT LOCATION 4B— 3
VACUUM HOSE ROUTING
DIAGRAM 4B— 5
SPECIFICATIONS 4B— 6
TROUBLESHOOTING GUIDE 4B— 7
TROUBLESHOOTING
PROCEDURE 4B— 7
TROUBLESHOOTING WITH SST.... 4B— 9
INSPECTION PROCEDURE 4B—10
AFTER-REPAIR PROCEDURE 4B—10
PRINCIPLE OF CODE CYCLE 4B—12
CODE NUMBER 4B—13
SWITCH MONITOR FUNCTION 4B—25
INSPECTION PROCEDURE 4B—26
IDLE SPEED 4B—29
IDLE MIXTURE 4B—29
INTAKE AIR SYSTEM 4B—30
COMPONENT DESCRIPTIONS 4B—30
REMOVAL 4B—31
PARTS INSPECTION 4B—32
INSTALLATION 4B—34
IDLE-UP SYSTEM 4B—35
COMPONENT DESCRIPTIONS 4B—36
TROUBLESHOOTING 4B—37
AIR VALVE 4B—38
AIR BYPASS SOLENOID VALVE ... 4B—39
FUEL SYSTEM 4B—42
COMPONENT DESCRIPTIONS 4B—43
TROUBLESHOOTING 4B—44
FUEL PRESSURE RELEASE AND
SERVICING FUEL SYSTEM 4B—45
MULTI-PRESSURE TESTER 4B—46
FUEL PRESSURE 4B—48
FUEL PUMP 4B—49
PULSATION DAMPER 4B—50
INJECTOR 4B—51
PRESSURE REGULATOR
CONTROL SYSTEM 4B—53
COMPONENT DESCRIPTIONS 4B—54
TROUBLESHOOTING 4B—55
REPLACEMENT 4B—57
FUEL TANK 4B—61
DECELERATION CONTROL
SYSTEM 4B—64
COMPONENT DESCRIPTIONS 4B—65
TROUBLESHOOTING 4B—66
AIR INJECTION SYSTEM 4B—68
COMPONENT DESCRIPTIONS 4B—68
TROUBLESHOOTING 4B—69
EXHAUST GAS RECIRCULATION
(EGR) SYSTEM 4B—71
COMPONENT DESCRIPTIONS 4B—71
TROUBLESHOOTING 4B—72
EVAPORATIVE EMISSION
CONTROL (EEC) SYSTEM 4B—74
COMPONENT DESCRIPTIONS 4B—74
TROUBLESHOOTING 4B—75
POSITIVE CRANKCASE
VENTILATION (PCV) SYSTEM 4B—80
COMPONENT DESCRIPTION 4B—80
EXHAUST SYSTEM 4B—81
REMOVAL AND INSTALLATION ... 4B—82
INSPECTION 4B—82
CONTROL SYSTEM 4B—83
RELATIONSHIP CHART 4B—84
EGI MAIN FUSE 4B—86
MAIN RELAY 4B—86
CIRCUIT OPENING RELAY 4B—86
ENGINE CONTROL UNIT 4B—87
NEUTRAL SWITCH 4B—91
CLUTCH SWITCH 4B—91
BRAKE LIGHT SWITCH 4B—91
P/S PRESSURE SWITCH 4B—92
INHIBITOR SWITCH 4B—92
E/L CONTROL UNIT 4B—93
AIR FLOW METER 4B—94
THROTTLE SENSOR 4B—95
WATER THERMO SENSOR 4B—97
WATER THERMO SWITCH 4B—97
OXYGEN SENSOR 4B—98
ATMOSPHERIC PRESSUFfE
SENSOR 4B—99
76G04B-001

4B OUTLINE
OUTLINE
SYSTEM DIAGRAM
S6U04A-0Q2
4B—2