check engine MAZDA 626 1987 Repair Manual

3A RADIATOR CAP
J I

V
J* J Q lanana
86U03X-028
86U03X-007
86U03X-008
3. Set the heater control switch to the maximum heat
position.
4. Flush the cooling system with water until all traces
of color are gone, then let the system drain com-
pletely.
5. Fill with the proper mixture and amount of ethy-
lene glycol-based coolant.
Caution
a) Do not use alcohol- or methanol-based
coolant.
b) Use only soft (demineralized) water in the
coolant mixture.
Anti-freeze solution mixture percentage

Protection Volume percentage Gravity
at

20°C (68°F) Protection Solution Water
Gravity
at

20°C (68°F)
Above -16°C (3°F) 35 65 1.054
Above -26°C (-15°F) 45 55 1.066
Above -40°C (-40°F) 55 45 1.078

6. Run the engine at idle with the radiator cap re-
moved. Let any air bleed from the system, and add
more coolant.
7. Install the radiator cap, and inspect all connections
for leakage.
RADIATOR CAP
INSPECTION
Radiator Cap Valve
1. Remove foreign material (such as water residue)
from between the radiator cap valve and the valve
seat.
2. Attach the radiator cap to a tester with the SST.
Apply pressure gradually to 74—103 kPa
(0.75—1.05 kg/cm2, 11—15 psi).
3. Wait about 10 seconds; then check that the pres-
sure has not decreased.
Negative Pressure Valve
1. Pull the negative-pressure valve to open it. Check
that it closes completely when released.
2. Check for damage on the contact surfaces, and
for cracked or deformed seal packing.
3. Replace the radiator cap if necessary.
86U03X-009
3A—6

RADIATOR 3A
RADIATOR
REMOVAL AND INSTALLATION
1. Drain the engine coolant.
2. Remove in the sequence shown in the figure.
3. Install in the reverse order of removal.
76G03A-005
5. Upper and lower radiator hose
6. Cooling fan and radiator assembly
7. Cooling fan
INSPECTION
Check the following points. Repair or replace if
necessary.
1. Cracks, damage, or water leakage
2. Bent fins (Repair with a screwdriver)
3. Distorted or bent radiator inlet.
Note
a) Position the hose clamp in the original location on the hose.
b) Squeeze the clamp lightly with large pliers to ensure a good fit. 86U03X-010
1. Coolant reservoir hose
2. ATF hose (ATX)
3. Water thermo switch connector
4. Cooling fan connector
86U03X-012
3A-7

THERMOSTAT 3A
69G03B-010
76G03A-008
76G03A-009
THERMOSTAT
REMOVAL
1. Drain the engine coolant.
2. Remove the thermostat cover.
3. Remove the thermostat.
INSPECTION
Check the thermostat. Replace if necessary.
1. Visually check that the valve is airtight.
2. Place the thermostat and a thermometer in water.
3. Gradually heat the water and check the following:
\ Model
Item
FEDOHC
FE 8-valve F8,F6...except
Middle
East General FE 12-valve
FE 8-valve, F8,F6...only Middle East General

Initial opening
tem-
perature

Sub
valve 83.5—86.5°C (182—188°F) Main valve 86.5—89.5°C (188—193°F)
86.5—89.5°C
(188—193°F)
80.5—83.5°C (177—182°F)
Full-open
temperature 100°C (212°F) 95°C (203°F)
Full-open
lift

Sub
valve
1.5
mm
(0.06 in) min.
Main valve
8.0
mm
(0.31 in) min.
8.5
mm
(0.33
in)min.

INSTALLATION
1. Install the thermostat into the cylinder head with
jiggle pin at the top.
2. Install a new gasket with the seal print side facing
the cylinder head.
3. Install the thermostat cover.
Tightening torque:
19—30
N
m (1.9—3.1 m-kg, 14—22 ft-lb)
4. Replenish the coolant.
5. Start the engine and check for leaks.
86U03X-018
3 A-11

3B COOLANT
86U03X-004
69G03A-006
COOLANT
INSPECTION
Coolant Level (Engine cold)
1. Check that the coolant level is near the radiator inlet
port.
2. Check that the coolant level in the coolant reser-
voir is between the FULL and Low marks.
Add coolant if necessary.
Warning
a) Never remove the radiator cap while the en-
gine is hot.
b)Wrap a thick cloth around the cap when
removing it.
Coolant Quality
1. Check that there is no build-up of rust or scales
around the radiator cap or radiator filler neck.
2. Check that coolant is free from oil.
3. Replace the coolant, if necessary.
Coolant Leakage
1. Connect a tester and SST to the radiator inlet port.
2. Apply 103 kPa (1.05 kg/cm2, 15 psi) pressure
to the system.
3. Check that the pressure is held.
If not, check for coolant leakage.
Warning
When removing either the radiator cap or the
tester, loosen it slowly until the pressure in
the radiator is released, and then remove it.
86U03X-005
REPLACEMENT
1. Remove the radiator cap and loosen the drain plug.
2. Drain the coolant into a suitable container.
Warning
a) Never open the radiator cap while the en-
gine is hot.
b)Wrap a thick cloth around the cap when
loosening.
c) Use caution when draining hot coolant.
86U03X-006
3B—4

RADIATOR CAP 3B
86U03X-028
86U03X-007
86U03X-008
3. Set the heater control switch to the maximum heat
position.
4. Flush the cooling system with water until all traces
of color are gone, then let the system drain com-
pletely.
5. Fill with the proper mixture and amount of ethy-
lene glycol-based coolant.
Caution
a) Do not use alcohol- or methanol-based
coolant.
b) Use only soft (demineralized) water in the
coolant mixture.
Anti-freeze solution mixture percentage

Protection Volume percentage Gravity
at

20°C (68°F) Protection Solution Water
Gravity
at

20°C (68°F)
Above —16°C (3°F) 35 65 1.054
Above -26°C (-15°F) 45 55 1.066
Above -40°C (-40°F) 55 45 1.078

6. Run the engine at idle with the radiator cap re-
moved. Let any air bleed from the system, and add
more coolant.
7. Install the radiator cap, and inspect all connections
for leakage.
RADIATOR CAP
INSPECTION
Radiator Cap Valve
1. Remove foreign material (such as water residue)
from between the radiator cap valve and the valve
seat.
2. Attach the radiator cap to a tester with the SST.
Apply pressure gradually to 74—103 kPa
(0.75—1.05 kg/cm2, 11—15 psi).
3. Wait about 10 seconds; then check that the pres-
sure has not decreased.
Negative Pressure Valve
1. Pull the negative-pressure valve to open it. Check
that it closes completely when released.
2. Check for damage on the contact surfaces, and
for cracked or deformed seal packing.
3. Replace the radiator cap if necessary.
86U03X-009
3B-5

3B RADIATOR
Note
a) Position the hose clamp in the original location on the hose.
b) Squeeze the clamp lightly with large pliers to ensure a good fit. 86U03X-010
RADIATOR
REMOVAL AND INSTALLATION
1. Drain the engine coolant.
2. Remove in the sequence shown in the figure.
3. Install in the reverse order of removal.
1. Coolant reservoir hose
2. Fast idle solenoid
3. Coolant level sensor connector
4. Cooling fan connector
76G03B-005
5. Upper and lower radiator hose
6. Cooling fan and radiator assembly
7. Cooling fan
INSPECTION
Check the following points. Repair or replace if
necessary.
1. Cracks, damage, or water leakage
2. Bent fins (Repair with a screwdriver)
3. Distorted or bent radiator inlet
86U03X-012
3B-6

THERMOSTAT 3B
THERMOSTAT
REMOVAL
1. Drain the engine coolant.
2. Disconnect the upper radiator hose, and water
thermo switch connector.
3. Remove the thermostat cover.
4. Remove the thermostat.
76G03B-010
76G03B-011
Sub valve Main valve
I
INSPECTION
Check the thermostat. Replace if necessary.
1. Visually check that the valve is airtight.
2. Place the thermostat and a thermometer in water.
3. Gradually heat the water and check the following:
Valve opening temperature
Sub valve : 78.5—81.5°C (173—179°F)
Main valve : 86.5—89.5°C (188—193°F)
Full open lift
Sub valve : 1.5 mm (0.06 in) min. at
100°C (212°F)
Main valve : 8 mm (0.31 in) min. at
100°C (212°F)
Valve closing temperature
Sub valve : 75°C (167°F)
Main valve : 83°C
(181
°F)
69G03B-012
76G03B-012
INSTALLATION
1. Install the thermostat into the thermostat case with
jiggle pin at the top.
2. Install a new gasket with the seal print side facing
the thermostat case.
3. Install the thermostat cover.
Tightening torque:
7—10 N-m (70—100 cm-kg, 61—87 in-lb)
4. Install the upper radiator hose and water thermo
switch connector.
5. Replenish the coolant.
6. Start the engine and check for leaks.
3B-9

4A
FUEL AND EMISSION
CONTROL SYSTEMS
(CARBURETOR)
OUTLINE 4A— 2
SYSTEM DIAGRAM 4A— 2
VACUUM HOSE ROUTING
DIAGRAM 4A— 5
EMISSION COMPONENTS
LOCATION 4A— 8
COMPONENT DESCRIPTIONS 4A—12
SPECIFICATIONS 4A—15
TROUBLESHOOTING GUIDE 4A—17
PARTS INSPECTION 4A—23
AIR CLEANER ELEMENT 4A—23
ACCELERATOR LINKAGE 4A—23
INTAKE MANIFOLD 4A—23
CHOKE CABLE 4A—23
FUEL SYSTEM 4A—24
TROUBLESHOOTING 4A—25
CARBURETOR 4A—26
FUEL PUMP 4A—35
FUEL TANK 4A—36
SEPARATOR 4A—37
TWO-WAY CHECK VALVE 4A—37
THREE-WAY CHECK VALVE 4A—37
FUEL FILTER 4A—37
IDLE SPEED AND IDLE MIXTURE.. 4A—38
ADJUSTMENT 4A—38
AUTO-RETURN CHOKE SYSTEM... 4A—40
TROUBLESHOOTING 4A—40
PTC HEATER SYSTEM 4A—42
TROUBLESHOOTING 4A—42
DECELERATION CONTROL SYSTEM 4A—45
TROUBLESHOOTING 4A—45
BYPASS AIR CONTROL SYSTEM.. 4A—48
DASH POT 4A—50
ANTI-AFTERBURN VALVE 4A—50
MAIN AIR BLEED CONTROL
SYSTEM 4A—51
SLOW FUEL CUT SYSTEM 4A—53
COAST ENRICHMENT SYSTEM .... 4A—54
COASTING LEANER SYSTEM 4A—56
AIR INJECTION SYSTEM 4A—58
INTAKE AIR TEMPERATURE CONTROL
SYSTEM 4A—60
TROUBLESHOOTING 4A—60
PURGE CONTROL SYSTEM 4A—63
VACUUM SWITCH VALVE 4A—63
EXHAUST GAS RECIRCULATION
(EGR) SYSTEM 4A—64
TROUBLESHOOTING 4A—65
POSITIVE CRANKCASE VENTILATION
SYSTEM 4A—67
PCV VALVE 4A—67
IDLE-UP CONTROL SYSTEM 4A—68
TROUBLESHOOTING 4A—70
IDLE-UP SOLENOID VALVE 4A—76
EVAPORATIVE EMISSION CONTROL
SYSTEM 4A—78
TROUBLESHOOTING 4A—79
IGNITION TIMING CONTROL
SYSTEM 4A-80
TROUBLESHOOTING 4A—81
CONTROL SYSTEM 4A-83
RELATIONSHIP CHART 4A—84
ENGINE CONTROL UNIT 4A—86
INHIBITOR SWITCH 4A—93
IDLE SWITCH 4A—93
VACUUM SWITCH 4A—94
WATER THERMO SWITCH 4A—95
EXHAUST SYSTEM 4A—96
76G04A-001

OUTLINE
4A

Previous

626
Unlead-
ed

fuel
O O O O O O X O O O X

Previous

626

Leaded
fuel
O X X O O X X X O X

New
626
FE
8
Valve
Unlead-
ed

fuel
o O O O O O X X O O O

New
626
Sin-
gapore

o O X O O m O
O

(FE

&
F8)
O
O

(FE

&
F8)
O O

New
626

Middle
East
o X X O O X X X X X O

New
626

General

X
O

(FE

& F8)
X O O X
O

(FE

&
F8)
O

(FE

&
F8)
O

(FE

&
F8)
X o

New
626
ECE
&

Hong
Kong
o O X O O * O O O O O o

Remark
• Adjustment
speed:

2,200

±
100
rpm
(in
neutral).
• MTX • Operation:
Coolant
tempera-

ture

more
than

50°C

(122°F).

Mechanical
type
Installed
on
carburetor.
Improvement
of
product
quality.

Function

Allows

throttle
to
gradually
close

during

deceleration.

Reduces

CO

and
HC
emission.

Detects

electrical
signal
from
in-
put
devices
and
controls
output
devices. Supplies
exhaust
gas
to
intake
manifold
to
reduce
NOx

Filters

fuel

Provides

fuel
to
carburetor.
Detects
when
throttle
valve
fully
closed. Opens
fuel

passage

to
secon-
dary
stage
of
carburetor.
Controls
shutter
valve
by
intake

air
temperature. Prevents
carburetor

icing.

Supplies
fresh
air
to
exhaust
manifold
to
reduce
CO
and
HC
emissions. Prevents
fuel
from
flowing
into

two-way

or
three-way
check

valve

Component

Dashpot Engine
Contorol
Unit

EGR

Control
Valve

Fuel

Filter

Fuel

Pump
Idle
Switch

Idle-up

Solenoid

Valve
Intake
Air
Temperature
Control
Valve

PTC

Heater

Reed

Valve

Separator

•a a> a -a .2-S
3
9-a a) 5 u- O UJ
z

Ox

111 IL •a c <o
x" Ul
V (-
U.ps •o<eo gfou-™
u.
-
X
_ X
I-
o-t-
s ®
s
*
o *
oo
x to
U. UJ
u.
T- oi CO
4 A—13

TROUBLESHOOTING GUIDE
4A

TROUBLESHOOTING GUIDE
F6 (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
Exhaust
system
Positive
crankcase
ventilation

system
Auto-return
choke
system

\\ POSSIBLE CAUSE
\ PAGE


SYMPTOM 4A—23 4A—60 4A—38 4A—24 4A—68 4A—96 4A—67 4A—40
1 Hard start
or
won't start (Cranks
OK)
1 2

2 Engine stalls During warm
up
3 2 1 4
2 Engine stalls After warm
up
4 2 5 1 3

3 Rough Idle During warm
up
3 2 1 4
3 Rough Idle After warm
up
3 2 5 1 4

4 High idle speed after warm
up
1 3 2

5 Poor acceleration, hesitation, or lack
of
power
1 2 3

6 Runs rough
on
deceleration
1

7 Afterburn
in
exhaust system
1

8 Poor fuel consumption
2 1 4 3

9 Fails emission test
2 1 4 5 3

76G04A-015
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
2nd Check Fuel and Emission Control Systems
Engine
1) Compression
2) Overheating
Others
1) Clutch slippage
2) Brake dragging
4 A-17