1987 MAZDA 626 engine

4A TROUBLESHOOTING GUIDE
FE and F8 (GENERAL)
The Troubleshooting Guide lists the systems most likely to cause a given symptom. After finding the
system(s) to check, refer to the pages shown for detailed guides for each system.
POSSIBLE CAUSE
\ PAGE
SYMPTOM

Air

cleaner

(Air

cleaner

element)

Intake

air

temperature

control

system

Idle

adjustment

Fuel

system

(Carburetor,

Fuel

pump)

Idle-up

control
system
PTC
heater
system
Positive
crankcase

ventilation

system

Deceleration

control
system
POSSIBLE CAUSE
\ PAGE
SYMPTOM 4A-23 4A—60 4A—38 4A—24 4A—68 4A—42 4A—67 4A—45
1 Hard start or won't start (Cranks OK) 1 2
2 Engine stalls During warm up 5 4 1 6 2 3 2 Engine stalls After warm up 3 2 4 1
3 Rough idle During warm up 5 4 1 6 2 3 3 Rough idle After warm up 3 2 4 1
4 High idle speed after warm up 1 4 2 3
5 Poor acceleration, hesitation, or lack of power 1 4 3 2
6 Runs rough on deceleration 2 1
7 Afterburn in exhaust system 2 1
8 Poor fuel consumption 2 1 3
9 Fails emission test 3 2 4 1
76G04A-018
The numbers of the list show the priorities of inspections from the most possible to that with the lowest
possibility.
These were determined on the following basis:
Ease of inspection Most possible system Most possible point in system
TROUBLESHOOTING PROCEDURE:
1st Check the following items:
Electrical system
1) Battery condition
2) Fuses
Ignition system
1) Spark plugs
2) Ignition timing
Fuel system
1) Fuel level
2) Fuel leakage
3) Fuel filter
4) Idle speed
Intake air system
1) Vacuum or air leakage
2) Vacuum hose routing
3) Accelerator cable
Engine
1) Compression
2) Overheating
Others
1) Clutch slippage
2) Brake dragging
2nd Check the Fuel and Emission Control Systems
4A—20

TROUBLESHOOTING GUIDE 4A
FE (MIDDLE EAST)
The Troubleshooting Guide lists the systems most likely to cause a given symptom. After finding the
system(s) to check, refer to pages shown for detailed guides for each system.
V. POSSIBLE CAUSE
\ PAGE
SYMPTOM

I
Air

cleaner

(Air

cleaner

element)

Intake

air

temperature

control

system

Idle

adjustment

Fuel

system

(Carburetor,

Fuel

pump)

Idle-up

control

system
Dashpot

(Only

MTX)

Positive

crankcase

ventilation

system
Exhaust
system

Evaporative

emission

control

system

Auto-return

choke

system

V. POSSIBLE CAUSE
\ PAGE
SYMPTOM 4A—23 4A-60 4 A—38 4A-24 4A-68 4A-50 4A-67 4A-96 4A-78 4A-40
1 Hard start or won't start
(Cranks OK) 1 2 3
2 Engine stalls During warm up 3 2 1 4 2 Engine stalls After warm up 3 2 4 1
3 Rough idle During warm up 3 2 1 4 3 Rough idle After warm up 3 2 4 1
4 High idle speed after warm up 1 5 3 4 2
5 Poor acceleration, hesitation, or lack of power 1 2 3
6 Runs rough on deceleration 2 1
7 Afterburn in exhaust system 3 1 2
8 Poor fuel consumption 5 1 6 2 3 4
9 Falls emission test 5 4 6 3 1 2
76G04A-019
The numbers of the list show the priorities of inspections from the most possible to that with the lowest
possibility.
These were determined on the following basis:
• Ease of inspection • Most possible system • Most possible point in system
TROUBLESHOOTING PROCEDURE:
1st Check the following items:
Electrical system
1) Battery condition
2) Fuses
Ignition system
1) Spark plugs
2) Ignition timing
Fuel system
1) Fuel level
2) Fuel leakage
3) Fuel filter
4) Idle speed
Intake air system
1) Vacuum or air leakage
2) Vacuum hose routing
3) Accelerator cable
4) Choke cable
Engine
1) Compression
2) Overheating
Others
1) Clutch slippage
2) Brake dragging
2nd Check the Fuel and Emission Control Systems
4 A—21

4A TROUBLESHOOTING GUIDE
FE 8VALVE—UNLEADED FUEL
The Troubleshooting Guide lists the systems most likely to cause a given symptom. After finding the
system(s) to check, refer to the pages shown for detailed guides for each system.
V POSSIBLE CAUSE
\ PAGE
SYMPTOM
Air

cleaner

(Air

cleaner

element)

Idle

adjustment

Fuel

system
(Carburetor,

Fuel

pump)
PTC

heater

system

Air

injection
system

Positive

crankcase

ventilation

system

Deceleration

control
system
Exhaust
gas

recirculation

(EGR)
system

Exhaust

system
Intake
air

temperature

control
system

Idle-up

control

system
Purge

control

system
Auto-return
choke
system
V POSSIBLE CAUSE
\ PAGE
SYMPTOM 4A-23 4A-38 4A-24 4A—42 4A-58 4A—67 4A—45 4A-96 4A-97 4A—60 4A—68 4A--63 4A—40
1 Hard start or won't start
(Cranks OK) 1 2
2 Engine stalls During warm up 6 1 2 5 3 4 2 Engine stalls After warm up 4 2 3 1
3 Rough Idle During warm up 5 1 2 4 3 6 3 Rough Idle After warm up 4 2 3 1
4 High idle speed after warm up 1 5 4 3 2
5 Poor acceleration, hesitation, or lack of power 1 2 5 3 4
6 Runs rough on deceleratio 2 1
7 Afterburn in exhaust system 2 1
8 Poor fuel consumption 4 1 2 3 5
9 Fails emission test 5 1 6 4 3 2
76G04A-020
The numbers of the list show the priorities of inspections from the most possible to that with the lowest
possibility.
These were determined on the following basis:
• Ease of inspection • Most possible system • Most possible point in system
TROUBLESHOOTING PROCEDURE:
1st Check the following items:
Electrical system
1) Battery condition
2) Fuses
Intake air system
1) Vacuum or air leakage
2) Vacuum hose routing
3) Accelerator cable
4) Choke cable
2nd Check the Fuel and Emission Control Systems
Ignition system
1) Spark plugs
2) Ignition timing
Engine
1) Compression
2) Overheating
Fuel system
1) Fuel level
2) Fuel leakage
3) Fuel filter
4) Idle speed
Others
1) Clutch slippage
2) Brake dragging
4A-22

4A FUEL SYSTEM
FUEL SYSTEM
This system consists of the fuel pump, fuel filters, and carburetor, and supplies the necessary fuel for
operation of the engine.
76G04A-025
4A—24

FUEL SYSTEM 4A
TROUBLESHOOTING
POSSIBLE CAUSE
\ PAGE Carburetor Fuel pump Separator
Two-way check valve (Except Middle East) Three-way check valve (Middle East)
SYMPTOM 4A—26 4A—35 4A—37 4A—37
1 Hard start or won't start (Cranks OK) 2 1
2 Engine stalls During warm up 2 1 2 Engine stalls After warm up 2 1
3 Rough idle During warm up 2 1 3 Rough idle After warm up 2 1
4 High idle speed after warm up 1
5 Poor acceleration, hesitation, or lack of power 2 1
6 Runs rough on deceleration 1
7 Afterburn in exhaust system 1
8 Poor fuel consumption 1 2 3
9 Fails emission test 1
76G04A-026
4A-25

4A FUEL SYSTEM
CARBURETOR
Removal
Remove in the sequence shown in the figure.
1. Secondary air hoses (If equipped) and air
cleaner
2. Water hoses
3. Fuel hose
4. Vacuum hoses
76G04A-027
5. Accelerator cable
6. Connector
7. Carburetor
8. PTC heater (If equipped)
9. Gasket (If equipped)
Installation
Install the reverse order of removal, referring following points.
1. Check for fuel leaks.
2. Check the vacuum hose installation.
3. Check the idle speed and idle mixture (Refer to page 4A—38).
4. Warm up the engine to the normal operating temperature and check that fuel level is at the center
of the float level indicator window.
4A—26

4A FUEL SYSTEM
76G04A-037
Float Level
Caution
This adjustment must be made without the
gasket on the air horn.
1. Turn the air horn upside-down and allow the float
to lower by its own weight.
2. Measure clearance H between the float and the
air horn.
Clearance H: 12.5 mm (0.49 in)
3. If not as specified, bend the float seat lip A to adjust.
4. Turn the air horn to the normal position and allow
the float to lower by its own weight.
5. Measure clearance L between the bottom of the
float and the air horn.
Clearance L: 44 mm (1.73 in)
6. If not as specified, bend the float stop B to adjust.
76G04A-038
76G04A-039
Fast Opening
F6 and FE 8Valve (Except General)
1. With the choke valve fully closed, measure the
clearance between the primary throttle valve and
the wall of the throttle bore.
Specification:
Engine Spec. Clearance mm (in)
F6 General and
Singapore 1.40—1.76
(0.055-0.069) FE 8Valve Middle East and
Unleaded Fuel
1.40—1.76
(0.055-0.069)
2. If not within specification, carefully bend the con-
necting rod to adjust.
4A—32

FUEL SYSTEM 4A
76G04A-040
76G04A-041
Clearance
® J t'YCL ® J
V hi /®
'-v
76G04A-042
Fast Idle Opening
FE and F8 (General, ECE, Hong Kong, and Sin-
gapore)
Adjustment of fast idle opening is normally un-
necessary.
But if it is necessary, adjust it as shown.
1. Before adjustment, let the carburetor set at 25WC
(77°F) for at least 1 hour.
2. Check that the center of the cam lever aligns with
the mark (25°) on the fast idle cam.
3. If not as specified, adjust it by turning the adjust
screw.
4. Measure the throttle valve clearance between the
throttle valve and wall with a wire gage.
Specification
Spec. General, ECE, Hong Kong,
and Singapore
Transmission MTX ATX
Clearance mm (in) 0.48—0.64
(0.019-0.025)
0.56—0.72 (0.022-0.028)
5. If not as specified, adjust it by turning the fast idle
adjust screw.
Unloader System
Only FE and F8 (General, ECE, Hong Kong, and
Singapore)
1. Open the primary throttle valve fully.
2. Measure the choke valve clearance.
Clearance-
1.68—2.14 mm (0.066—0.084 in)
3. If not as specified, adjust it by bending tab A.
Slow Fuel Cut Solenoid Valve
1. Start the engine, and run it at idle.
2. Disconnect the connector of the carburetor.
3. Check that the engine stops.
4. If the engine does not stop, replace the slow fuel
cut solenoid valve.
76G04A-043
4A-33