fuel MAZDA 626 1987 Workshop Manual

4B FUEL SYSTEM
Operating time Fuel line pressure kPa
(kg/cm2, psi)
After starting: for 120
sec.
235-275
(2.4—2.8, 34—40)
After 120 sec, 186-226 (1.9-2.3, 27-33)
6. Restart the engine.
7. Check the fuel line pressure and operating times
as shown in the chart.
76G04B-127
Solenoid Valve (Pressure Regulator Control)
Inspection
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.
86U04A-098
Air filter
Apply 12V
Port (J)
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 the vacuum
hose A.
7. Check that air flows from the valve air filter.
86U04A-099
4B-56

FUEL SYSTEM 4B
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 4B—45).
b)When servicing the fuel system, keep
sparks, cigarettes, and open flames away
from the fuel.
76G04B-077
86U04A-101
M Fuel pump
Fuel filter
Bracket
86U04A-102
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
securely.
6. Install in the reverse order of removal.
4B—57

4B FUEL SYSTEM
76G04B-078
76G04B-079
Insulator
Injector
Grommet
Delivery
pipe
Pressure regulator
76G04B-080
Injector O-ring Correct
1 #J
Grommet Delivery pipe
Wrong
£a
/
^ Wrong IF
Injector
1. Disconnect the air pipe from the throttle body.
2. Disconnect the air hose from the throttle body.
3. Disconnect the delivery pipe from the intake
manifold.
4. Lift the delivery pipe along with the pressure regu-
lator and pulsation damper.
5. Remove the grommets, injectors, and insulators.
6. Install in the reverse order of removal, referring to
installation note.
Tightening torque:
Delivery pipe 19—25 N-m
(1.9—2.6 m-kg, 14—19 ft-lb)
Installation note
Injector
1. Use new O-rings.
2. Apply a small amount of engine oil to the O-rings
when installing.
86U04A-108
4B-58

FUEL SYSTEM 4B
3. Install the injectors and the injector insulators.
86U04A-109
Delivery Pipe
1. Remove the pulsation damper and pressure regu-
lator from the delivery pipe.
2. Remove the injectors (Refer to page 4B—58).
76G04B-081
Replace the delivery pipe.
Install in the reverse order of removal, referring to
installation note.
Tightening torque:
Pressure regulator
8—11 Nm (0.8—1.1 m-kg, 69—95 in-lb)
Delivery pipe
19—25
N
m (1.9—2.6 m-kg, 14—19 ft-lb)
76G04B-082
Installation note
Injector
Refer to page 4B—58.
4B—59

4B FUEL SYSTEM
Pressure Regulator
1. Disconnect the vacuum hose and fuel return hose.
2. Remove the pressure regulator.
3. Install in the reverse order of removal.
Tightening torque:
8—11 N-m (0.8—1.1 m-kg, 69—95 in-lb)
76G04B-084
Pulsation Damper
1. Loosen the pulsation damper and remove it.
2. Install in the reverse order of removal.
76G04B-085
^-Fuel hose
ML*? ^-Fuel pump
^silntank filter
ti* e
76G04B-086
h
tS

Is o
Sjfbj
Fuel Filter
Low pressure side
Refer to page 4B—57.
86U04A-116
High pressure side
The fuel filter must be replaced at the intervals out-
lined in the maintenance schedule.
Warning
Always work away from sparks or open
flames.
1. Disconnect the fuel hoses from the fuel filter.
2. Remove the fuel filter and the bracket.
3. Install a new filter and the bracket.
4. Connect the fuel hoses.
Note
When installing the filter, push the fuel hoses
fully onto the fuel filter and secure the hoses
with spring clamps.
4B-60

FUEL SYSTEM 4B
FUEL TANK
Removal
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 4B—45)
b) When removing the fuel tank, keep sparks, cigarettes, and open flames away from the
fuel tank.
Remove in the sequence shown in the figure.
76G04B-087
Note
Drain the fuel from the fuel tank before removing the tank.
1. Fuel pump connectors 5. Breather hose
2. Fuel hoses 6. Fuel tank strap
3. Evaporative hoses 7. Fuel tank
4. Fuel filler hose
4B—61

4B FUEL SYSTEM
Inspection
1. Check the fuel tank for cracks and corrosion.
2. If any defect is found, repair or replace the tank.
Warning
Before repairing, clean the fuel tank thorough-
ly with steam to sufficiently remove all explo-
sive gas.
86U04A-118
Installation
Install in the reverse order of removal, referring to the installation note.
Torque Specifications
22—30 N-m (2.2—3.1 m-kg, 16—22 ft-lb)
4B—62
86U04A-119

FUEL SYSTEM 4B
Fuel filler hose: Push in at least 35 mm (1.4 in)
Others: At least 25 mm (1.0 in)
Installation note
1. Push the hose ends of the main fuel hose, fuel re-
turn hose and evaporation hoses onto the fuel tank
fittings at least 25 mm (1.0 in).
2. Push the fuel filler hose ends onto the fuel tank pipe
and filler pipe at least 35 mm (1.4 in).
86u04a-120
4B-63

4B DECELERATION CONTROL SYSTEM
DECELERATION CONTROL SYSTEM
This system consists of the dashpot and fuel cut system. The dashpot is to prevent after-burn so that
the throttle valve gradually closes during deceleration.
The control unit detects engine deceleration judging from the engine speed and the idle switch, and
signals a fuel cut operation to match the engines need, based on the coolant temperature and the
driving condition.
4B—64

DECELERATION CONTROL SYSTEM 4B
COMPONENT DESCRIPTIONS
Component Function Remarks
Brake light switch Detects braking operation (deceleration);
sends signal to engine control unit
Clutch switch Detects in-gear condition;
sends signal to engine control unit Switch ON when clutch pedal released
Dashpot (MTX) Prevents sudden closing of throttle valve during deceleration or shifting Adjustment speed: 1,900—2,100 rpm
Engine control unit Detects signals from input sensors and switches; cuts fuel injection
Idle switch Detects when throttle valve fully closed; sends signal to engine control unit Installed in throttle sensor
Ignition coil (-) terminal Detects engine speed; sends signal to engine control unit
Neutral switch Detects in-gear condition; sends signal to engine control unit Switch ON when in-gear
Water thermo sensor Detects coolant temperature; sends signal to engine control unit
Water thermo switch Detects radiator coolant temperature; sends signal to engine control unit ON: above 17°C (63°F)
76G04B-089
4B—65