1987 MAZDA 626 Workshop Manual

4C FUEL SYSTEM
^ Pulsation
damper
76G04C-121
Pulsation damper
—
Delivery pipe
76G04C-122
Fuel hose
,Fuel pump
-Intank filter
76G04C-123
Insulator
f f r—
/ 0 DM

•
II r
O - ring
Grommet
Manifold
Delivery pipe
Pressure Regulator
1. Remove the engine hanger.
2. Disconnect the vacuum hose and fuel return hose.
3. Remove the pressure regulator.
4. Install in the reverse order of removal.
Tightening torque:
8—11 Nm (0.8—1.1 m-kg, 69—95 in-lb)
Pulsation Damper
1. Remove the delivery pipe assembly. (Refer to page
4C-63.)
2. Remove the pulsation damper.
3. Install in the reverse order of removal.
Tightening torque:
25—34 N m (2.5—3.5 m-kg, 18—25 ft-lb)
Fuel Filter
Low pressure side (In-tank filter)
Refer to page 4C—60.
76G04C-124
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 them with
spring clamps.
4C-64

FUEL SYSTEM 4C
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 4C—52.)
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.
76G04C-125
Note
Drain the fuel from the fuel tank before removing the tank.
1. Remove fuel filler cap.
2. Fuel pump connectors
3. Fuel hoses
4. Steering angle transfer shaft (4-wheel
steering)
(Refer to section 10)
5. Cross member (4-wheel steering)
6. Evaporative hoses
7. Fuel filler hose
8. Breather hose
9. Parking cable bracket
10. Fuel tank strap
11. Fuel tank
4C-65

4C 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 remove all explosive fuel and
fumes.
Installation
Install in the reverse order of removal, referring to the installation note.
Torque Specifications
4C-66
76G04C-126

FUEL SYSTEM 4C
Installation note
Hoses
1. Push the ends of the main fuel hose, fuel return
hose, and evaporation hoses onto the fuel tank fit-
tings at least 25 mm (1.0 in).
2. Push the fuel filler hose onto the fuel tank pipe and
filler pipe at least 35 mm (1.4 in).
Steering angle transfer shaft
(4-wheel steering)
Refer to section 10
4C—67

4C PRC SYSTEM
PRESSURE REGULATOR CONTROL
(PRC)
SYSTEM
Distributor (Ne signal)
I Fuel
(To fuel tank)
76G04C-128
To prevent percolation of the fuel during idle after the engine is restarted, vacuum is cut to the pres-
sure regulator, increasing the fuel pressure.
Specified time: Approx. 120 sec.
Operating condition: Coolant temperature — above 70°C (158°F)
Intake air temperature — above 30°C (86°F)....Unleaded fuel
above 50°C (122°F)....Leaded fuel
4C-68

PRC SYSTEM 4C
COMPONENT DESCRIPTION
Component Function Remark
Engine control unit Detects signals from input sensors and switches; con-trols solenoid valve (Pressure regulator control)
Ignition switch
(ST position)
Sends engine cranking signal to engine control unit
Intake air thermo sensor Detects intake air temperature; sends signal to engine control unit
Ne signal pick-up Detects crank angle at 180° intervals; sends signal to engine control unit Installed in distributor
Pressure regulator Adjusts fuel pressure supplied to injectors
Solenoid valve (Pres-
sure regulator control)
Controls vacuum to pressure regulator Cuts vacuum when hot
Water thermo sensor Detects coolant temperature; sends signal to engine control unit
Idle switch Detects when throttle valve closed; sends signal to engine control unit ON at idle
76G04C-129
TROUBLESHOOTING
Check the condition of the wiring harness and connections before checking the sensors or switches.
Note
Make the system inspection first. If no problem is found, continue with inspection of the
next system of the Troubleshooting Guide. (Refer to pages 4C—10 and 11.)
Possible
\ cause
\ Page
Solenoid valve (Pres-sure regula-tor control)
Water thermo
sensor
Intake air
thermo
sensor
Engine con-trol unit terminal
System inspection Solenoid valve (Pres-sure regula-tor control) 2K
Symplon 4C—70 4C—107 4C-110 4C—98 4C—70
Engine stalls or runs rough after hot starting 2 3 4 5 1
76G04C-130
4C-69

4C PRC SYSTEM
System Inspection
1. Connect the SST to the engine. (Refer to page
4C-53.)
2. Start the engine.
76G04C-131
Hi?
Jpll ssil
Water thermo sensor ^^^Tta^e air thermo sensor
76G04C-132
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)
3. Warm up the engine to normal operating temper-
ature and stop the engine.
Warning
Be careful when disconnecting the water ther-
mo sensor connector because the surround-
ing area is very hot.
4. Disconnect the water thermo sensor connector.
Connect a resistor (200 fl) to the sensor connector.
5. Heat the intake air thermo sensor to above specifi-
cation.
Specification: 30°C (86°F)....unleaded fuel
50°C (122°F)....leaded fuel
6. Restart the engine.
7. Check the fuel line pressure and operating times
as shown in the chart.
76G04C-133
Solenoid Valve (Pressure Regulator Control)
Inspection
1. Disconnect the vacuum hose from the vacuum
pipe.
2. Blow through the solenoid valve from vacuum hose
A.
3. Check that air flows from port B.
76G04C-134
4C—70

PRC SYSTEM 4C
Apply 12V
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
4C-71