1987 MAZDA 626 heater

4A OUTLINE
EMISSION COMPONENTS LOCATION
ECE, Hong Kong, and Singapore
Dashpot*
Reed valve
Solenoid valve*2 (Ignition timing control system)
Vacuum switch*5
Anti-afterburn valve
Choke opener
Idle-up solenoid valve^*5
or coasting leaner*6
Water thermo switch
Thermo valve*6
Water thermo switch
PTC heater*5
Air bypass solenoid valve*3
Solenoid valve*5
(Choke opener)
jr'-f
Choke breaker diaphragm
Solenoid valve*5 (Main air bleed control system)
Solenoid valve (P/S)*1
Solenoid valve (A/C)*1
Engine control unit
Fuel pump
*1 If equipped
*2 FE and F8 ATX
*3 F8 MTX and FE
*4 MTX
*5 FE and F8
*6 F6
76G04A-008
4A—8

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 x" Ul
V (-
U.ps •o u.
-
X
_ X
I-
o-t-
s ®
s
*
o *
oo
x to
U. UJ
u.
T- oi CO
4 A—13

TROUBLESHOOTING GUIDE
4A

FE
12
VALVE and
F8
(EXCEPT MIDDLE EAST and 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)
PTC
heater
system

Air

injection
system
Positive
crankcase
ventilation
system
Deceleration
control
system

Idle-up

control
system

Ignition

control
system

POSSIBLE CAUSE
\ PAGE
SYMPTOM

4A-23 4A-60 4A-38 4A-24 4A-42 4A-58 4A-67 4A—45 4A—68 4 A—80
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 3 2

5 Poor acceleration, hesitation, or lack
of
power
1 4 2 3

6 Runs rough
on
deceleration
2 1

7 Afterburn
in
exhaust system
2 1

8 Poor fuel consumption
3 1 4 2
4
9 Fails emission test
6 2 5 3 1 4

76G04A-017
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—19

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

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
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 PTC HEATER SYSTEM
PTC HEATER SYSTEM
[FE
and
F8 engine (except Middle
East)]
76G04A-071
The PTC heater system consists of the PTC heater, relay, and water thermo switch. The system is
designed to prevent carburetor icing when the engine operating temperature is low t assure optimum
driveability.
TROUBLESHOOTING
Note
Make the system inspection first. If no problem is found, continue with the next inspec-
tion of the Troubleshooting Guide. (Refer to pages 4A—19, —20, or—22)
FE 8Valve—Unleaded Fuel
Possible cause System
inspection
Water thermo switch (intake manifold)
PTC heater
Water
thermo
switch
(Radiator)
PTC heater
relay
Page 4A—43 4A—41 4A—43 4A—95 4A—44
Checking order 1 2 3 4 5
Except FE 8Valve—Unleaded Fuel
Possible cause System inspection
Water thermo switch (Radiator)
PTC heater PTC heater
relay
Page 4A—43 4A—95 4A—43 4A—44
Checking order 1 2 3 4
76G04A-072
4A-42

PTC HEATER SYSTEM 4A
System Inspection
Except FE 8Valve—Unleaded Fuel
1. Connect a voltmeter to the PTC heater connector.
2. Start the engine and measure the voltage.
Specification
Radiator coolant
temperature Below 17°C (63°F) Above
17°C (63°F)
Voltage Approx. 12V ov
76G04A-073
FE 8Valve—Unleaded Fuel
1. Start the engine.
2. Connect a voltmeter to the PTC heater connector
terminals and measure the voltage.
Voltage
Engine coolant
temperature
Below 67°C (152°F)
Above 67°C (152°F)
Radiator coolant temperature Below 17°C (63°F) Above 17°C (63°F) —
Terminal BrB Approx.
12V
OV OV Terminal BrW
Approx.
12V Approx. 12V OV
76G04A-074
PTC Heater
Except FE 8Valve—Unleaded Fuel
1. Disconnect the PTC heater connector.
2. Check for continuity of the heater with an
ohmmeter.
76G04A-075
FE 8Valve—Unleaded Fuel
1. Disconnect the PTC heater connector.
2. Check for continuity between terminal wire (BrW)
and a ground.
3. Check for continuity between terminal wire (BrB)
and (B).
76G04A-076
4A—43