water MAZDA 626 1987 Owners Manual

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

2K
— — —

2L
(BR) Inhibitor switch "P"
or "N"
range Below 1,5V 2L
(BR) Inhibitor switch
Others Battery voltage
2M
(BY)
Ignition switch
(START position)
Ignition switch
ON
Below 1,5V 2M
(BY)
Ignition switch
(START position) Cranking Battery voltage
2N
— — —
76G04A-172
(2M X
2
X
2F 2C

X 2L
2J 2H 2F 2D 2B

fll X >< X

1J 1H
>< X
1B

FE and F8 Engine — MTX (General)
Terminal (Wire color) Connected to Condition Voltage

A
(W)
Headlight switch Headlight switch
ON
Below 1,5V A
(W)
Headlight switch
Headlight switch OFF Battery voltage
B
(B)
Ground
—
Below 1,5V
C
(BL) Rear defroster switch Rear defroster switch
ON
Below 1,5V C
(BL) Rear defroster switch
Rear defroster switch OFF Battery voltage
D
(LG) A/C switch A/C operated Below 1.5V D
(LG) A/C switch
A/C not operated Battery voltage
E
(LB) Solenoid valve (Main
air

bleed control)
Intake manifold vacuum more than 300 mmHg (11.8 inHg), and radiator coolant temperature above 17°C (63 °F)
Battery voltage E
(LB) Solenoid valve (Main
air

bleed control)
Others Below 1.5V
F
(GW)
Water thermo switch
(Radiator)
Radiator coolant temperature below 17°C (63°F) Below 1,5V F
(GW)
Water thermo switch
(Radiator) Radiator coolant temperature above 17°C (63°F) Battery voltage
G (YL)
Ignition coil Ignition switch
ON or
engine running Battery voltage
H
(L)
Water thermo switch (Intake manifold) Engine coolant temperature below 72°C (162°F) Below 1,5V H
(L)
Water thermo switch (Intake manifold) Engine coolant temperature above 72°C (162°F) Battery voltage
I
— — —

J
(BW)
Ignition switch Ignition switch
ON
Battery voltage
K
— —

L
— — —

M
— — —

N
— —
4A-90

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

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

TROUBLESHOOTING WITH SST 4B
CODE NUMBER
Malfunction display
Self-diagnosis Fail-safe Code
No. Output signal pattern subsystem Self-diagnosis Fail-safe

01
ON
OFF

Ignition pulse
No ignition signal
08
Air flow meter
Open
or
short circuit
Maintains basic sig-
nal
at
preset value
09
1 111

Water thermo sensor
Open
or
short circuit
Maintains constant command 35°C (95 °F)
10
Intake
air
thermo sensor (air flow meter) Open
or
short circuit
Maintains constant 20°C (68°F) command
12
£_IUILJIIL

Throttle sensor
Open
or
short circuit
Maintains constant
command
of
throttle
valve fully open
14
OFF
TL
I I nil

Atmospheric pres-
sure sensor Open
or
short circuit
Maintains constant command
of
sea level pressure
15
oTp m 11 [U

Oxygen sensor Sensor output con-tinues less than 0.55V 120 sec. after engine starts (1,500 rpm)
Cancels EG
I
feed-
back operation
17
SLJlMJl

Feedback system Sensor output
not
changed
20
sec.
af-
ter engine exceeds 1,500 rpm
Cancels EGI feed-back operation
25
^JMLJl

Solenoid valve (pres-
sure regulator)
Open
or
short circuit
26
SUUBUIL

Solenoid valve (purge control)
Open
or
short circuit 28
£ mi in nr

Solenoid valve
(EGR) Open
or
short circuit
34
^jmiUTT

Air bypass solenoid
valve (Idle-up
C)

Open
or
short circuit
35
0Nnnnj OFFU u UUU
"fin nnr
Air bypass solenoid
valve (Idle-up
B)

Open
or
short circuit

76G04B-008
Caution
a) If there is more than one failure present, the lowest number malfunction code is dis-
played first, the remaining codes are displayed sequentially.
b) After repairing a failure, turn off the ignition switch and disconnect the negative battery
cable and depress the brake pedal for at least 2 seconds to erase the memory of a mal-
function code.
4B-13

4B TROUBLESHOOTING WITH SST
Code No. 09 (Water thermo sensor) PC: Possible Cause

Are there poor connections
at
water thermo sensor circuit?

NO
YES
Repair
or
replace connector
Is there continuity between water thermo sensor and control unit?
Water thermo sensor Control unit
A (YB wire) 21
B (LgY wire) 2C

YES

Is resistance
of
the water thermo sensor OK? Resistance:
Coolant temp Resistance
-20°C
(
-4°F) 14.5-17.8 k£2
20°C
(
68°F) 2.2- 2.7
kQ

40°C (104°F) 1.0- 1.3
kfi

60°C (140°F) 500—640
Q

80°C (176°F) 280-350
Q
NO
PC: Open circuit
in
wiring harness from water thermo sensor
to
engine control unit

NO
Replace water thermo sensor

| YES

Is same Code No. present after performing after-
repair procedure? (Refer
to
page 4B—10)

YES

Are engine control unit
21
OK? (Refer
to
page 4B—8
and
2C
terminal voltages
3)

NO
Water thermo sensor and circuit
OK
NO
PC: Engine short circuit
in
wiring harness

YES

PC: Engine control unit malfunction

76G04B-011
4B—16

SWITCH MONITOR FUNCTION 4B
SWITCH MONITOR FUNCTION
Individual switches can be monitored by the SST.
Note
The test connector must be grounded and the ignition switch ON (engine stopped).
Control unit
76G04B-022
Switch Self-Diagnosis Checker (Monitor lamp) Remarks Switch Light ON Light OFF Remarks

Clutch switch Pedal released Pedal depressed Gear:
IN

Neutral switch In gear Neutral Clutch pedal released
Idle switch Pedal depressed Pedal released
—

Brake light switch Pedal depressed Pedal released
—

A/C switch ON OFF Blower motor position:
"1"

position
Headlight switch ON OFF
—

Rear defroster switch ON OFF
—

Blower switch ON OFF Blower motor position:
"3"
or
"4"
position
Inhibitor switch D,
1, 2
and
R
range P and
N
range
—

Water thermo switch (Elec-trical fan) Terminal disconnected Terminal connected While fan
not
operating

4B-25

4B SWITCH MONITOR FUNCTION
Headlight switch
76G04B-030
Rear defroster switch
76G04B-031
Inhibitor switch
76G04B-032
Water thermo switch circuit (not included in switch inspection)
Warning
4B—28

INTAKE AIR SYSTEM 4B
REMOVAL
Caution
Before removing the following parts, release the fuel pressure from fuel system to reduce
the possibility of injury or fire. (Refer to page 4B—45.)
Remove in the sequence shown in the figure.
1. Air flow meter connector
and secondary air hose
2. Air cleaner
3. Air duct
4. Resonance chamber
5. Air flow meter
6. Air hose
7. Vacuum hoses, air hoses,
and water hoses
8. Accelerator cable
9. Throttle sensor connector
10. Throttle body
11. EGR modulator valve
12. Air hose
13. Air bypass solenoid valve
76G04B-038
14. Intake manifold bracket
15. Dynamic chamber bracket
16. Fuel return pipe
17. Dynamic chamber
18. Injector connector
19. Delivery pipe assembly
20. Air valve
21. Intake manifold and gaskets
4B—31

INTAKE AIR SYSTEM 4B
76G04B-039
D C B E\\ I I A
p 'V > "
F G
76G04B-040
76G04B-041
1. Check that the throttle valve moves smoothly when
the throttle lever is moved from fully closed to fully
open.
2. Warm up the engine and run at idle.
3. Check the vacuum generated at each port as
shown in the following table.

~ —Condition
Port (Connected to) ——____ Idle Other
A (solenoid valve, EGR) No Yes
B (distributor, advance) No Yes
C (EGR modulator valve) No Yes
D (water thermo valve) No Yes
E (vacuum switch valve
&
charcoal canister) Yes
F (distributor, retard
& air
control valve) Yes
G (distributor, advance) Yes

4. If vacuum is not obtained as in the table, clean the
necessary port.
Dynamic Chamber
1. Visually check the dynamic chamber for damage.
2. Replace, if necessary.
Intake Manifold
1. Visually check the intake manifold for damage.
2. Replace, if necessary.
76G04B-042
4B—33

IDLE-UP SYSTEM 4B
IDLE-UP SYSTEM
Dynamic chamber
To engine i
lN
Water thermo |ntake air sensor thermo
sensor
E/L control unit
-D
Solenoid A
From air ^^ flow meter ~
Engine
control
unit
Atmospheric pressure sensor
HI
f
"Solenoid B
UJ m
Solenoid C
u
Adjusting screw
| A/C
H-!
relay
IGN switch
-©n
To engine
control
unit
Magnetic clutch
fftf
tr Main relay
r © ©
P/S pressure switch
76G04B-043
Air Valve
This valve is constructed so that the gate valve is opened and closed by means of a bimetal strip and
heat coil. It acts as a fast idle mechanism by opening the gate valve to increase intake air by bypass-
ing the throttle valve while engine is cold, therefore engine speed is increased to shorten the warm
up period.
Air Bypass Solenoid Valve
This valve incorporates three solenoid valves. They operate according to the signal from the engine
control unit or A/C switch in order to achieve idling stability and the optimum idle speed.
The operating conditions of each solenoid valve are as shown below.
Solenoid valve Operating condition

A A/C operated
B Intake air temp, above 55°C (131 °F)
or
vehicle
at
above 1,000
m
(3,280
ft)

C P/S operated, E/L applied, intake
air
temp, above 55°C (131 °F), pressure regulator solenoid ON
or
vehicle
at
above 1,900
m
(6,232
ft)
4B-35