1987 MAZDA 626 air condition

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
IDLE
SPEED AND
IDLE
MIXTURE
76G04A-059
76G04A-060
76G04A-061

IDLE
SPEED AND IDLE MIXTURE
ADJUSTMENT
Note
a) Before adjusting the idle speed and idle
mixture, be sure the ignition timing, spark
plugs, carburetor float level, etc., are all in
normal operation condition.
b)Turn off all electrical loads.
c) This adjustment must be done while the fan
motor is not operating.
Idle Speed
1. Connect a tachometer to the engine.
2. Warm up the engine, and check that the choke
valve has fully opened.
3. Check the idle speed.
Specification
MTX ATX (in N range)
Specification Others
FE 8Valve Unleaded fuel F6 F8 & FE
Idle speed rpm 800 +6S 850 +5S 950 +5o° 900 +5§
4. If not within specification, adjust the idle speed by
turning the throttle adjust screw.
Caution
After adjusting the idle speed, the dashpot ad-
justment should be checked and adjusted if
necessary.
Idle Mixture
[Except FE 8Valve—Unleaded Fuel]
Adjust the idle mixture as follows, after adjusting the
idle speed.
1. Disconnect the secondary air hoses from the reed
valves and plug them. (If equipped.)
2. Insert an exhaust gas analyzer into the tail pipe and
measure the CO concentration.
CO concentration: 2.0 ± 0.5%
3. If not within the specification, remove the blind cap
from the mixture adjust screw.
76G04A-062
4A—38

4 A DECELERATION CONTROL SYSTEM
TROUBLESHOOTING
Check the condition of the wiring harness and connectors before checking the engine control unit
or switches.
FE 12Valve and F8 (ECE, Hong Kong and Singapore)—MTX
Possible cause
Page
Symptom

Anti-afterburn

valve
Dashpot Bypass
air
control
system
Idle

switch
main
air

bleed

control
system

Engine

control

unit

terminal
Possible cause
Page
Symptom

Anti-afterburn

valve
Dashpot Bypass
air
control
system
Idle

switch
main
air

bleed

control
system
E L M
Possible cause
Page
Symptom 4A—50 4A—50 4A—48 4A—93 4A—51 4A—88
Runs rough on deceleration 2 1 3 5 4
Afterburn in exhaust system 1 2 4 3 5 6
Poor fuel consumption 1 2 3
Fails emission test 7 6 1 2 3 4 5
High idle speed after warm up 1 2 3
Engine stalls during warm up 1
Rough idle during warm up 1
Poor acceleration, hesitation, or lack of power 1
76G04A-079
FE 12Valve and F8 (ECE, Hong Kong and Singapore)—ATX
Possible cause o> o 4-* uT u. E 3
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Symptom 4A—50 4A—48 4A—51 4A—93 4A—86
Runs rough on deceleration 2 3 1 5 4
Afterburn in exhaust system 1 2 3 4 5
Poor fuel consumption 1 2
Fails emission test 7 6 2 1 3 4 5
High idle speed after warm up 1 2
Engine stall during warm up 1
Rough idle during warm up 1
Poor acceleration, hesitation, or lack of power 1
76G04A-080
4A—46

4A IDLE-UP CONTROL SYSTEM
IDLE-UP SOLENOID VALVE
FE and F8 (General, ECE, Hong Kong, and Singapore)
Water thermo switch Fan speed control switch Headlights _
Rear defroster
A/C
Engine1
control -
unit
Richer air bleed
Richer jet
/ '
Inhibitor switch
Water thermo switch Fan speed _ control switch Headlights -
Rear defroster —
A/C
Engine
control
unit
Idle-up solenoid valve
Adjust screw
Secondary
throttle valve
From secondary main jet
76G04A-151
The idle-up solenoid valve opens when the following conditions are met.
Condition
When inhibitor switch is OFF (ATX—other than "P" and "N" range) and any of the following:
• Engine coolant temperature less than 72°C (162°F).
• A/C operated.
• Fan speed control switch 3rd or 4th position.
• Headlights turned on.
• Rear defroster turned on.
4A—76

IGNITION TIMING CONTROL SYSTEM 4A
TROUBLESHOOTING
Check the condition of the wiring harness and components before checking the sensors or switches.
\\ Possible cause , . Engine control unit terminal
\ Page

rater

thermo

switch

itake

manifold)

'ater

thermo

switch

Iadiator)
hibitor

switch

Solenoid

valve

(Ignition

timing

contra

0) >
5 >> n
acuum

control

unit

Ustributor)
Symptom \J

•S-
o 5 t c
Solenoid

valve

(Ignition

timing

contra

O > B 1F 2A 2F 2H 2M Symptom \J 4A—95 4A—95 4A—93 4A—81 4A—82 Section 5 4A—85 4A--86
Poor accelera-
tion, hesitation, 5 6 4 2 3 1 11 7 8 9 10 or lack of power
Fails emission test 4 5 3 2 — 1 10 6 7 8 9
76G04A-161
Solenoid Valve (Ignition Timing Control)
1. Disconnect the vacuum hose from the solenoid
valve and vacuum pipe.
2. Blow through the solenoid valve from vacuum hose
A.
3. Check that air flows from port B.
76G04A-162
4. Disconnect the solenoid valve connector.
5. Connect 12V and a ground to the terminals of the
solenoid valve.
6. Blow through the solenoid valve from vacuum hose
A.
7. Check that air flows from the valve air filter.
76G04A-163
4 A—81

4A CONTROL SYSTEM
ENGINE CONTROL UNIT
Check the engine control unit terminal voltages with
a voltmeter.
Caution
a) Warm up the engine before checking the
control unit.
b) If the proper voltage is not obtained, check
the wiring, connections and finally, check
the component.
FE and F8 Engine — ATX (ECE, Hong Kong, and Singapore)
Terminal
(Wire color) Connected to Condition Voltage

1A
(BW)
Ignition switch Ignition switch ON. Battery voltage

m
ST
'-O
Solenoid valve (Main
air
bleed control) Others Battery voltage
m
ST
'-O
Solenoid valve (Main
air
bleed control) Radiator coolant temperature below 17°C (63°F)
or
intake manifold vacuum more than 200 mmHg (7.9 inHg)
Below 1,5V
1C (GO) Solenoid valve (Choke opener) Radiator coolant temperature below 17°C (63°F)
or
during cranking and
27
sec. after engine starts Below 1,5V
Others Battery voltage
1D
(GL)
Air bypass solenoid valve Idle switch OFF and engine speed above approx. 2,100 rpm Below 1,5V
Others Battery voltage
1E
— — —

1F
(G) Solenoid valve (Ignition timing control system)
Radiator coolant temperature above 17°C (63°F),
en-
gine coolant temperature below 72°C (162°F), inhibi-tor switch OFF and engine speed below 2,300
rpm

Below 1.5 V
Others Battery voltage
1G
— — —

1H
(LW) Solenoid valve (A/C) A/C switch
ON
and engine speed below approx. 2,300
rpm

Below 1,5V
Others Battery voltage
11
(YW) Idle-up solenoid valve Inhibitor switch OFF and, headlight switch ON, rear
defroster switch ON, fan speed control switch
is 3rd

or 4th position, A/C operated,
or
engine coolant tem-
perature below 72°C (162°F)
Below 1,5V
Others Battery voltage
1J
(B)
Ground
—
Below 1,5V

9 MSSirSl
ivj
A 1
k *
76G04A-169
4A—86