1987 MAZDA 626 Workshop Manual

4C FUEL SYSTEM
86U04A-078
76G04C-097
76G04C-098
„\W cLTest connector (Yellow)
'-/jumper wire \\ \ •
5. Disconnect the vacuum hose from pressure regu-
lator, and place a finger over the end of the hose.
6. Check the fuel line pressure.
Fuel line pressure: 235—275 kPa
(2.4—2.8 kg/cm2, 34—40 psi)
7. If not within specification, replace the pressure
regulator.
8. Connect the vacuum hose to pressure regulator.
FUEL PUMP
Operation Test
1. Connect a jumper wire to the test connector
(Yellow).
2. Remove the fuel filler cap.
3. Disconnect transfer pump connector (8-pin).
4. Turn the ignition switch ON.
5. Listen for operational sound of the fuel pump at
the filler inlet.
6. Install the fuel filler cap.
7. If no sound was heard, check the voltage at the
fuel pump connector (WY wire and a ground).
Voltage: 12V
8. If the voltage is normal, replace the fuel pump.
9. If not correct, check the control relay and circuit
(Refer to page 4C—96.)
10. Disconnect the jumper wire.
Volume Test
Warning
Before performing the following procedures,
release the fuel pressure from the fuel system
to reduce the possibility of injury or fire.
(Refer to page 4C—52)
1. Connect a jumper wire to test connector (Yellow).
2. Disconnect the fuel return hose from fuel return
pipe.
76G04C-099
4C-56

FUEL SYSTEM 4C
Pulsation damper
76G04C-100
Intake mainfold
3. Turn the ignition switch ON for 10 seconds, and
check the feeding capacity with graduated
cylinder.
Feeding capacity:
Minimum 220 cc (13.4 cu in)/10 sec.
4. If not within specification, check the fuel filter, fuel
lines and fuel pump.
5. Turn the ignition switch OFF and disconnect the
jumper wire.
PULSATION DAMPER
1. Run the engine at idle.
2. Place a finger on the screw of the pulsation damper
head.
3. Check that pulsation is felt.
86U04A-083

Injector
INJECTOR
On-vehicle Inspection
1. Warm up the engine and run it at idle.
2. Listen for operational sound of the injector with a
screwdriver or a sound scope.
76G04C-101
3. Ground the test connector (Green, 1-pin).
76G04C-102
4C-57

4C FUEL SYSTEM
76G04C-103
76G04C-104
76G04C-105
- s A Test connector I \ (Yellow)
4. Disconnect the connector from each injector
respectively.
5. Check that the engine speed decreases about
100—200 rpm each time.
6. If not correct, check the following:
No operating sound and no speed drop
Check injector wiring harness
No speed drop only
Injector resistance
Injection volume of injector
Inspection
Perform the following inspections.
Resistance
1. Remove the injectors from the engine. (Refer to
page 4C—61.)
2. Check the resistance of each injector with an
ohmmeter.
3. If not correct, replace the injector.
Resistance: 12—16 Q
Fuel leakage test and volume test
1. Remove the injectors and delivery pipe. (Refer to
pages 4C—61 and 63.)
2. Affix the injectors to the delivery pipe with wire.
Caution
Affix the injectors firmly so that no movement
is possible.
Warning
Be extremely careful when working with fuel.
Always work away from sparks or open
flames.
3. Connect the terminals of the test connector (Yel-
low) with a jumper wire. Turn the ignition switch ON.
4. Check that no fuel leaks from the injector nozzles.
Note
After 1 minute, a drop of fuel from the injec-
tor is acceptable.
76G04C-106
4C—58

FUEL SYSTEM 4C
5. Connect the SST to the battery and injector.
6. Check the injection volume with a graduated con-
tainer.
Injection volume:
Approx. 66—91 cc (4.03—5.55 cu in) /15 sec.
Caution
When using the SST, make sure of the SST
number and use correct one.
7. If not correct, replace the injector.
76G04C-107
Rear seat Cushion Release Button -
76G04C-108
TRANSFER PUMP CONTROL SYSTEM (4 WHEEL
STEERING)
1. Remove the rear seat. (Refer to 14 section.)
2. Remove the fuel filler cap.
3. Turn the ignition switch ON.
Note
a) The tank should be more than 1/3 full.
b) Due to the delay timer, transfer pump oper-
ation begins approx. 10 sec. after the igni-
tion switch is turned ON.
4. Listen for the operational sound of the transfer
pump.
5. Install the fuel filler cap.
6. If no sound was heard, check the voltage at the
transfer pump connector.
Terminal (wire) Voltage
A, C (WG) Approx. 12V
I, J (B) OV
86U04B-075
I C A
lb d
cp a • • •
J
76G04C-211
7. If the voltages are correct, replace the transfer
pump.
8. If not correct, disconnect the transfer pump con-
nector.
9. Check the voltage at the terminals below.
Terminal (wire) Voltage
A, C (WG) Approx. 12V
I, J (B) OV
10. If the voltages are correct, replace the transfer
pump.
4C—59

4C FUEL SYSTEM
BW B
11. If not correct, check the voltage at terminals of the
fuel pump control unit.
76G04C-109
76G04C-110
86U04A-101
Fuel pump
Fuel filter
Bracket
76G04C-111
Terminal (wire) Voltage
A(B) Approx. 12V
C (BW) OV
12. If the voltages are correct, replace the fuel pump
control unit.
13. If not correct, repair the power supply circuit or the
ground circuit for the fuel pump control unit.
REPLACEMENT
Caution
A)Before performing the following procedure,
release the fuel pressure from the fuel sys-
tem to reduce the possibility of injury or fire.
(Refer to page 4C—52.)
b)When servicing the fuel system, keep
sparks, cigarettes, and open flames away
from the fuel.
Fuel Pump
1. Remove the rear seat and disconnect the fuel
pump connector.
2. Remove the service hole cover.
3. Disconnect the fuel hoses.
4. Remove the fuel pump and fuel tank gauge as-
sembly.
5. Replace the fuel pump.
Caution
Secure the fuel pump terminals and fuel hoses
tightly.
6. Install in the reverse order of removal.
4C—60

FUEL SYSTEM 4C
76G04C-112
86U04B-083
76G04C-113
Transfer Pump
1. Remove the fuel tank. (Refer to page 4C—65.)
2. Disconnect the fuel hoses from the transfer pump.
3. Remove the transfer pump.
4. Install in the reverse order of removal.
Injector
1. Remove the engine hanger.
2. Remove the wiring harness bracket.
3. Disconnect the PCV valve and hose from the dy-
namic chamber.
76G04C-114
4C-61

4C FUEL SYSTEM
4. Disconnect the main fuel hose from the delivery
pipe assembly.
5. Disconnect the fuel return hose from the fuel re-
turn pipe.
6. Remove fuel return pipe mounting bolt.
76G04C-115
7. Remove the delivery pipe assembly mounting bolts
and insulators.
76G04C-116
Remove the grommets, injectors, and insulators.
Install in the reverse order of removal, referring to
the installation note.
Tightening torque:
Delivery pipe, dynamic chamber, and en-
gine hanger
19—25 N m (1.9—2.6 m-kg, 14—19 ft-lb)
76G04C-117
O-ring Injector / Correct
v L
Grommet Delivery pipe
Wrong
/
Dc^Li Wrong
Installation note
Injector
1. Use new O-rings.
2. Apply a small amount of engine oil to the O-rings
when installing.
86U04A-108
4C-62

FUEL SYSTEM 4C
3. Install the injectors and the injector insulators.
86U04A-109
O-ring
Grommet
Injector
Insulator
Bolt
,J| Delivery
XM P'pe
\1 \>_ - ( ^ ,r- Insulator
Insulator
Install the insulators between the intake manifold and
the delivery pipe.
76G04C-118
Delivery Pipe
1. Remove the injectors. (Refer to page 4C—61.)
2. Separate the fuel return pipe from the delivery pipe
assembly.
76G04C-119
3. Replace the delivery pipe.
4. Install in the reverse order of removal, referring to
the installation note.
Tightening torque:
Fuel return pipe 8—11 N-m
(0.8—1.1 m-kg, 69—95 in-lb)
76G04C-120
4C-63