1987 MAZDA 626 oil

4 A DECELERATION CONTROL SYSTEM
BYPASS AIR CONTROL SYSTEM
FE and F8 [Except General and Middle East]
E -tr Air bypass solenoid valve
I
Engine
control
unit
FE 8 Valve — Unleaded fuel

J
f^^n
Ignition coil
Idle switch
76G04A-084
The bypass air control system consists of the bypass solenoid valve, idle switch, ignition coil, and en-
gine control unit.
This system opens the bypass air passage to the intake manifold during deceleration above ap'prox.
2,300 rpm (ECE, Hong Kong, and Singapore), or above approx. 3,500 rpm (FE 8 Valve—Unleaded
fuel).
Note
Make the system inspection first. If no problem is found, continue with the next inspec-
tion of the Troubleshooting. (Refer to page 4A—46 or 47.)
Troubleshooting
Possible cause System inspection Air bypass solenoid valve
Page 4A-48 4A-49
Checking order 1 2
/
/o fcl i /o ' jXj^/* J
V\ i \\ I M
p)
/ Terminal AGL...Leaded Fuel
L LB...FE 8 Valve—Unleaded Fuel
System Inspection
1. Warm up the engine and run it at idle.
2. Connect a tachometer.
3. Disconnect the bypass air hose from the air cleaner
and place a finger over the hose opening.
76G04A-085
4A—48

4 A DECELERATION CONTROL SYSTEM
COAST ENRICHMENT SYSTEM [FE 8VALVE—UNLEADED FUEL]
Ignition coil
Engine
control
unit
Coast enrichment
solenoid valve
Richer air bleeds
Secondary main
air bleed
Idle switch
© e
To secondary
main jet
76G04A-098
This system opens the fuel passage to the secondary stage of the carburetor during deceleration at
engine speeds of 2,300—1,500 rpm. The coast enrichment solenoid valve is actuated by the engine
control unit.
Troubleshooting
Possible cause System Inspection Coast enrichment solenoid valve
Engine control unit terminal Possible cause System Inspection Coast enrichment solenoid valve
A B D 1
Page 4A—54 4A—55 4A—91
Checking order 1 3 2
System Inspection
1. Warm up the engine to the normal operating tem-
perature and run it at idle.
2. Connect a voltmeter to the carburetor connector
terminal E.
3. Connect a tachometer to the engine.
76G04A-099
4A—54

4A DECELERATION CONTROL SYSTEM
COASTING LEANER SYSTEM (F6 SINGAPORE MTX)
Coasting leaner
0 oAir
a n, © © Battery Ignition
switch Secondary
throttle valve
| / Relay
Engine control unit
Ignition coil
76G04A-102
This system consists of the coasting leaner solenoid valve, engine control unit, ignition coil, and idle switch.
When the idle switch is ON and the engine speed is more than approx. 2,100 rpm (deceleration),
the coasting leaner solenoid valve opens the air passage port to prevent afterburn in the exhaust system.
Troubleshooting
Note
Make the system inspection first. If no problem is found, continue with the next inspec-
tion of the Troubleshooting. (Refer to page 4A—47)
Possible cause System inspection Coasting leaner solenoid valve Relay
Page 4A—56 4A—57 4A—57
Checking order 1 2 3
Coasting leaner System Inspection
1. Warm up the engine and run it at idle.
2. Connect a tachometer to the engine.
3. Connect a voltmeter to the coasting leaner sole-
noid valve connector (LgB wire).
76G04A-103
4A—56

4 A IGNITION TIMING CONTROL SYSTEM
IGNITION TIMING CONTROL SYSTEM
F8 and FE (12-VALVE)—ATX (ECE, Singapore, and Hong Kong)
Ignition coil
76G04A-160
This system consists of the distributor, solenoid valve, and several switches, vacuum to the vacuum
control unit of the distributor is cut when the conditions below are met.
Item Condition
Engine speed Below 2,300 rpm
Selector lever position Other than P and N range
Coolant temperature Engine coolant: below 72°C (162°F) Radiator coolant: above 17°C (65°F)
4A—80

CONTROL SYSTEM 4 A
CONTROL SYSTEM
Idle switch A/C switch
Water thermo switch
'Vacuum switch
Engine control switch
£
-Ignition coil
V
Water thermo switch
•Inhibitor switch
76G04A-166
The control system consists of the engine control unit, water thermo switches, A/C switch, P/S switch,
inhibitor switch, vacuum switch, and idle switch.
4A—83

4A CONTROL SYSTEM
RELATIONSHIP CHART
O: Related
X
: Not
related
IGNITION COIL
X X
O O O
X
O
X

WATER
THERMO
SWITCH
RADIATOR O O
X X X X
o O WATER
THERMO
SWITCH INTAKE
MANIFOLD o
X X X X
O o
X

VACUUM SWITCH
X X X X X X X
O
IDLE SWITCH
X X
O O O
X X X

A/C SWITCH
X X X X X
O
X X

P/S SWITCH
X X X X X X X X

E/L SWITCHES
/ Headlight Switch


( Rear defroster switch
J

\ Fan speed control switch
/
X X X X X
O
X X

INHIBITOR SWITCH
X X X X X
O O
X

ENGINE CONTROL UNIT
X
o O O O O o O

\
INPUT

DEVICE

AND
ENGINE

CONTROL

UNIT

OUTPUT
DEVICE
PTC
HEATER

CHOKE

OPENER
(FE
and
F8
—
ECE,
Hong
Kong,
&

Singapore)

COASTING
LEANER
COAST

ENRICHMENT

SOLENOID

VALVE
AIR

BYPASS
SOLENOID
VALVE
IDLE-UP
SOLENOID
VALVE
IGNITION
TIMING
CONTROL
SYSTEM
MAIN
AIR
BLEED
CONTROL
SYSTEM

*
FE
8Valve—Unleaded Fuel:
O
(Related)
General and
FE
12Valve—ECE, Hong Kong, Singapore:
X
(Not related)

76G04A-167
4A—84

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

2A
(YL)
Ignition coil Ignition switch
ON or
engine running Battery voltage
2B (LB) Fan speed control switch Fan speed control switch
in
3rd
or
4th position Below 1.5 V 2B (LB) Fan speed control switch
Fan speed control switch OFF Battery voltage
2C
(BL)
Rear defroster switch Rear defroster switch
ON
Below 1,5V 2C
(BL)
Rear defroster switch
Rear defroster switch OFF Battery voltage
2D
(LG)
A/C switch A/C operated Below 1,5V 2D
(LG)
A/C switch
A/C not operated Battery voltage
2E
(RG)
Headlight switch Headlight switch OFF Below 1.5 V 2E
(RG)
Headlight switch
Headlight switch
ON
Battery voltage
2F
(GW)
Water thermo switch
(Radiator)
Radiator coolant temperature below 17°C (63°F) Below 1.5V 2F
(GW)
Water thermo switch
(Radiator) Radiator coolant temperature above 17°C (63°F) Battery voltage
2G
-— —

2H
(L)
Water thermo switch (In-
take manifold)
Engine coolant temperature below 72°C (162°F) Below 1,5V 2H
(L)
Water thermo switch (In-
take manifold) Engine coolant temperature above 72°C (162°F) Battery voltage
21
(LY)
Vacuum switch Vacuum less than 200 mmHg (7.9 inHg) Below 1.5V 21
(LY)
Vacuum switch
Vacuum more than 200 mmHg (7.9 inHg) Battery voltage
2J (RL) OD release solenoid valve Engine coolant temperature below 72°C (162°F) Below 1.5V 2J (RL) OD release solenoid valve
Engine coolant temperature above 72°C (162°F) Battery voltage
2K
(-)

— — -

2L (BR)
Inhibitor switch "N"
or "P"
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
(LsB) Idle switch Idling Battery voltage 2N
(LsB) Idle switch
Accelerator pedal depressed Below 1,5V

76G04A-170

{ 2M 2K 21
X
2F 2C
2A

2N 2L 2J 2H 2F 2D 2B
(11 X X
1C 1 A^j
1J 1H 1F 1D 1B

FE and F8 Engine — MTX (ECE, Hong Kong, and Singapore)
Terminal (Wire color) Connected to Condition Voltage

A
(RG) Headlight switch Headlight switch
ON
Below 1,5V A
(RG) Headlight switch
Headlight switch OFF Battery voltage
B
(B)
Ground
—
Below 1,5V

4A-87

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

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 (LY) 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 (LY) 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
J (BW) Ignition switch Ignition switch
ON
Battery voltage
K (GO) Solenoid valve (Choke opener) Radiator temperature below 17°C (63°F)
or
during cranking and
27
sec. after engine starts Below 1,5V K (GO) Solenoid valve (Choke opener)
Others Battery voltage
L (LsB) Idle switch Idling Battery voltage L (LsB) Idle switch
Accelerator pedal depressed Below 1,5V
M
(GL)
Air bypass solenoid valve Idle switch OFF and engine speed above approx. 2,100 rpm Below 1,5V M
(GL)
Air bypass solenoid valve
Others Battery voltage
0
(BY)
Ignition switch
(START position)
Ignition switch
ON
Below 1,5V 0
(BY)
Ignition switch
(START position) Cranking Battery voltage
P
(LW) Solenoid valve (A/C) A/C switch
ON
and engine speed below approx.
2,300
rpm

Below 1,5V P
(LW) Solenoid valve (A/C)
Others Battery voltage
Q (YW) Idle-up solenoid valve Headlight switch ON, rear defroster switch ON,
fan
speed control switch
is
3rd
or
4th position, A/C oper-ated,
or
engine coolant temperature below 72°C (162°F)
Below 1,5V Q (YW) Idle-up solenoid valve
Others Battery voltage
R
(LB)
Fan speed control switch Fan speed control switch
in
3rd
or
4th position Below 1,5V R
(LB)
Fan speed control switch
Fan speed control switch OFF Battery voltage

76G04A-171

f ° O M K I G E C
R P N L J H F D B

4A-88