1987 MAZDA 626 fuel

4 A FUEL SYSTEM
76G04A-044
76G04A-045
76G04A-046
Choke Breaker Diaphragm
1. Warm up the engine to the normal operating tem-
perature, then stop the engine.
2. Set the choke valve to the fully closed position.
3. Apply 400 mmHg (15.7 inHg) vacuum to the di-
aphragm.
4. Measure the clearance between the choke valve
and air horn with a wire gauge.
Cl68r8ncG'
2.45—3.11 mm (0.096—0.122) FE, F8
1.68—2.14 mm (0.066—0.084 in) F6
5. If not within specification, adjust by bending the
lever.
Choke Opener
ECE, Hong Kong, Singapore, and Middle East
1. Warm up the engine to the normal operating tem-
perature, then stop the engine.
2. Set the choke valve to the fully closed position.
3. Apply 400 mmHg (15.7 InHg) vacuum to the di-
aphragm.
4. Measure the clearance between the choke valve
and air horn with a wire gauge.
Specification Clearance mm (in)
ECE, Hong Kong, and Singapore
(Except F6 MTX) 3.7—4.0 (0.15—0.16)
Middle East 3.3—3.6 (0.13—0.14)
F6 Singapore MTX 3.2—3.5 (0.13—0.14)
5. If not within specification, adjust by bending the
connecting rod.
76G04A-047
4A-34

FUEL SYSTEM 4 A
76G04A-048
76G04A-049
FUEL PUMP
Inspection
Fuel pressure
1. Disconnect the hose at the carburetor and connect
a fuel pressure gauge.
2. Disconnect the fuel return hose from the fuel pump
and plug the fuel pump return pipe as shown in
the figure,
3. Measure the pressure while the engine is idling.
Replace the pump, if necessary.
FE & F8 (ECE,
Hong Kong,
Singapore)
Others
Pressure kPa
(kg/cm2, psi)
20—29 (0.2-0.3, 2.8-4.3)
20-26
(0.20-0.27,
2.8-3.8)
Flow rate (volume)
1. Disconnect the carburetor fuel hose and insert the
end into a measuring breaker.
2. Disconnect the fuel return hose from the fuel pump
and plug the fuel pump return pipe as shown in
the figure.
3. Start the engine and measure the amount of fuel
pumped per minute.
Volume: More than 860 cc (52.5 cuin)/min
Removal
1. Remove in the following order.
(1) Fuel outlet hose
(2) Fuel inlet hose
(3) Fuel return hose
(4) Fuel pump
(5) Gasket
(6) Insulator
(7) Gasket
76G04A-050
Installation
Install in the reverse order of removal.
Caution
a) Replace the gasket whenever the fuel pump
is replaced.
b) Be sure to connect the hoses in the correct
positions.
Check for leaks.
76G04A-051
4A—35
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4A FUEL SYSTEM
FUEL TANK
Removal
1. Remove the rear seat cushion.
2. Remove the cover and disconnect the fuel tank
gauge unit connector.
3. Disconnect the fuel main and return hoses.
4. Raise the vehicle and support it with safety stands.
5. Remove the fuel level gauge unit assembly.
Warning
a) When repairing the fuel tank, clean it
thoroughly with steam to remove all explo-
sive gasoline and fumes.
b) Use of fire is strictly prohibited while work-
ing on the fuel tank.
6. Drain the fuel.
7. Disconnect the remaining hoses.
8. Remove the fuel tank.
Inspection
1. Check the fuel tank for cracks and corrosion.
2. If any defect is found, repair or replace the tank.
3. Check for leaks.
Torque Specifications
76G04A-054
4A—36
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76G04A-052
76G04A-053
Installation
Install in the reverse order of removal.

FUEL SYSTEM 4A
SEPARATOR
Inspection
Visually check the separator for fuel leakage and dam-
age. Replace, if necessary.
76G04A-055
TWO-WAY CHECK VALVE
(Except Middle East)
Inspection
1. Disconnect the hoses, and remove the check
valve.
2. Check that air flows in both directions through the
valve.
3. If not as specified, replace the two-way check
valve.
76G04A-056
THREE-WAY CHECK VALVE
(Middle East)
1. Blow through the valve from port and check
that air comes out of port (§).
Next, block port ©and check that air comes of
port ©.
2. Block port ©and apply vacuum with a vacuum
pump through port
3. Check that no vacuum is held.
76G04A-057
FUEL FILTER
Replacement
The fuel filter is mounted on the left side of the frame.
Caution
a) To prevent gasoline from draining during
removal, first disconnect and plug the in-
let hose.
b) During installation be sure to install the fuel
filter in the correct direction of flow.
76G04A-058
4 A—37

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

IDLE SPEED AND IDLE MIXTURE 4A
76G04A-063
76G04A-064
4. Turn the mixture adjust screw to adjust the CO con-
centration.
5. Recheck the idle speed.
6. Fit a new blind cap onto the mixture adjust screw.
Idle Mixture [FE 8Valve—Unleaded Fuel]
Adjustment of the idle mixture is normally un-
necessary.
But if it is necessary, adjust it as follows.
Note
Do not insert the exhaust gas analyzer into the
tail pipe.
Before adjust the idle mixture, check and set
the idle speed.
1. Disconnect the secondary air hoses.
2. Insert an exhaust gas analyzer into the hose and
plug it to prevent leakage.
3. Start the engine and run it at idle.
4. Measure the CO concentration.
5. Remove the blink cap from the mixture adjust
screw.
6. Turn the mixture adjust screw and adjust the CO
level.
CO concentration: 2.0 ± 0.5%
7. If the idle speed fails to meet specification as the
result of the above steps, adjust the idle.
8. Reconnect the secondary air hoses.
9. Fit a new blind cap onto the mixture adjust screw.
76G04A-065
4A-39

4 A AUTO-RETURN CHOKE SYSTEM
AUTO-RETURN CHOKE SYSTEM
[FE 8VALVE—UNLEADED FUEL, MIDDLE EAST, and F6—GENERAL]
r ~ I
76G04A-066
An auto-return choke is adopted to prevent the catalytic converter from over-heating because of over
use of the choke. This system opens the choke valve by causing the choke knob to return when the
engine coolant temperature is more than 67°C (153°F).
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—16, 21, or 22)
Possible cause
" ^ Page
Symptom
System inspection Choke magnet Water thermo switch
Possible cause
" ^ Page
Symptom 4A—40 4A—41 4A—41
Checking order 1 2 3
76G04A-067
System Inspection
1. Make sure that the engine is cold and turn the ig-
nition switch ON.
2. Pull out the choke knob and check that it is held on.
3. Start the engine and check that the choke knob
returns during warming-up.
76G04A-068
4A—40

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