1992 MAZDA PROTEGE fuel pump

F TROUBLESHOOTING GUIDE
STEP INSPECTION ACTION
5 Check for correct fuel line pressure at idle Yes Check if fuel line pressure decreases
w page F-129 when accelerating quickly
Fuel line pressure: + If it decreases, check for clogging
265-314 kPa (2.7-3.2 kg/cm’, 36-46 psi) between fuel pump and pressure
(Vacuum hose to pressure regulator dis- regulator
connected) * If not decrease, go to next step
INSTALL CLAMPS No Low pressure
Check fuel line pressure while pinching
fuel return hose
c3 If fuel line pressure quickly in-
creases, check pressure regulator w page F-129
c3 If fuel line pressure gradually in-
creases, check for clogging be-
tween fuel pump and pressure
regulator
If not clogged, check fuel pump
maximum pressure w page F-126
6 Check if cooling system is OK Yes Go to next step
w page E-13
No Repair or replace
l Thermostat w page E-9
l Electric cooling fan w page E-16 l Radiator w page E-6
7 Try known good ECU and check if condition Yes Replace ECU CT page F-149
improves
CT= page F-149 No
Change fuel to another brand or use
higher octane fuel
23lJOFX.0: .-._ ,
F-72

SELF-DIAGNOSIS FUNCTION F
TEP
6
7
8
9
IO
11 INSPECTION
Check for correct fuel line pressure at idle
IV page F-122
Fuel line pressure:
265-314 kPa (2.7-3.2 kg/cm’, 38-46 psi)
(Vacuum hose to pressure regulator
disconnected)
Check intake air system components for air
leakage
Check for misfire of dead cylinder from Step 5
inspection
Check for injector operating sound at idle of
dead cylinder from Step 5 inspection -
Replace injector at dead cylinder from Step 5 in-
spection
CI page F-131
Check if same Code No. is present following
performing after-repair procedure
CT page F-104
Try known good ECU and check if condition
Improves
CT page F-149 Yes
No
Yes If not clogged, check fuel pump
maximum pressure
Go to Step 11
No Replace
--
Yes Repair or replace ignition system
No
Yes
No
Yes
No
T L ACTION
Go to next step
Low pressure
Check fuel line pressure while pinching
fuel return hose
~3 If fuel line pressure quickly in-
creases, check pressure regulator
v page F-129
c3 If fuel line pressure gradually in-
creases, check for clogging be-
tween fuel pump and pressure
regulator
CT page F-126
Go to next step
Go to next step
Check for battery voltage at injector
connector terminal-wire (W/R)
L3 If Yes, replace injector c7 page F-131
+ If No, check wire harness for short
or open
Go to next step
Removed injector at fault
Circuit Diagram
ATX
OXYGENSENSOR
R/L
ECU
-------------- ---
BILG
23UOFX-07
F-10'

F FUEL SYSTEM
FUEL SYSTEM
DESCRIPTION
FUEL FILTER
(HIGH PRESSURE SIDE) . TANK
FUEL PUMP
PRESSURE SIDE)
OWOFX-12
This system supplies the necessary fuel for combustion at a constant pressure to the fuel injectors. Fuel is
metered and injected into the engine intake ports according to injection control signals from the engine con-
trol unit. The system consists of the fuel tank, the fuel pump, the fuel filters, the delivery pipe, the pressure
regulator, the fuel injectors, and the circuit opening relay. ._*
F-l 20

FUEL PUMP CONNECTOR
/
REAR SEAT C
FUEL SYSTEM F
PRECAUTION
Fuel Pressure Release and Servicing Fuel System
Fuel in the fuel system remains under high pressure even when
the engine is not running.
a) Before disconnecting any fuel line, release the fuel pres-
sure from the fuel system to reduce the possibility of injury
or fire.
1. Start the engine.
2. Push the rear seat cushion buttons and remove the
cushion.
3. Disconnect the fuel pump connector.
4. After the engine stalls, turn off the ignition switch.
5. Reconnect the fuel pump connector and install the rear
seat cushion.
b) Use a rag as protection from fuel spray when disconnect-
ing the hoses.
Plug the hoses after removal.
c) When inspecting the fuel system, use a suitable fuel pres-
sure gauge.
Caution
l Install hose clamps to secure the fuel pressure
gauge to the fuel filter and the fuel main hose to pre-
vent fuel leakage.
9MUOF2-122 OBUOFX-126
DlAGNOS&O,NNECTOR
03UOFX-12.
-
DISCONNECT CONNECTOR
/ TO RELEASE FUEL PRESSURE
03UOFX-12;
Priming Fuel System
After releasing the fuel pressure for repairs or inspection, the
system must be primed to avoid excessive cranking when first
starting the engine. Follow the steps below.
1. Connect the diagnosis connector terminals
F/P and GND
with a jumper wire.
2. Turn the ignition switch
ON for approx. 10 sec. and check
for fuel leaks.
3. Turn the ignition switch OFF and remove the jumper wire.
SYSTEM OPERATION
Fuel Pressure Hold Inspection
Warning
l Before performing the following operation, release
the fuel pressure from the fuel system to reduce the
possibility of injury or fire. (Refer to above.)
F-121

F FUEL SYSTEM
OSUOFX-129
DIAGNOSIS.\CO.NNECTOR j
/, I 23UOFX-104
DISCONNECT CONNECTOR
TO RELEASE FlJsL PRESSURE
L 23UOFX-105
INSTALL CLAMPS
DIAGNOSI$kO)lNECTOfl
I
23UOFX-ll
F-l 22
1. Disconnect the negative battery terminal.
2. Install a fuel pressure gauge between the fuel pipe and the
fuel main hose. (Install clamps as shown.)
3. Connect the negative battery terminal. J
4. Connect the diagnosis connector terminals
F/P and GND
with a jumper wire.
5. Turn the ignition switch ON for
10 sec. to operate the fuel
pump.
6. Turn the ignition switch OFF and disconnect the jumper wire.
7. Observe the fuel pressure
after 5 min..
Fuel pressure:
More than 147 kPa (1.5 kg/cm2, 21 psi)
8. If not as specified, perform the following inspections.
l Fuel pump hold pressure. (Refer to page F-125.)
l Pressure regulator hold pressure.
(Refer to page F-129.)
l Injector fuel leakage. (Refer to page F-132.)
Fuel Line Pressure Inspection
Warning
l Before performing the following operation, release
the fuel pressure from the fuel system to reduce the
possibility of injury or fire. (Refer to page F-121.) __,
1. Disconnect the negative battery cable.
2. Install a fuel pressure gauge between the filter and the fuel
main hose. (Install clamps as shown.)
3. Connect the negative battery cable.
4. Connect diagnosis connector terminals
F/P and GND with
a jumper wire.
5. Turn the ignition switch ON.
6. Measure the fuel line pressure.
Fuel line pressure:
265-314 kPa (2.7-3.2 kg/cm2, 38-46 psi)
Pressure low - Measure fuel pump maximum pressure.
(Refer to page F-126.) If as specified,
fuel line or fuel filter might be clogged or
restricted.
Pressure high - Replace pressure regulator.
(Refer to page F-130.)

FUEL SYSTEM F
FUEL TANK
Removal / Inspection / Installation
Warning
l Before performing the following operation, release the fuel pressure from the fuel system to
reduce the possibility of injury or fire. (Refer to page F-121 .)
l When removing the fuel tank, keep sparks, cigarettes, and open flames away from it.
l Before repair the fuel tank, clean it throughly with steam to remove all explosive gas.
1. Remove in the order shown in the figure.
2. Inspect the fuel tank components visually and repair or replace if necessary.
3. Install in the reverse order of removal, referring to
Installation Note.
7.8-l 1 N.m (80-l 10 cm-kg,
7.8-i 1 N-m (80-I 10 cm-kg, 89-95 in-lb) 69-95 in-lb)
N.m (m-kg, ft-lb]
23UOFX-107
Note
l Drain the fuel from the fuel tank before removing the tank.
1. Fuel pump cover 7. Fuel tank
2. Fuel pump connector Inspect for cracks and corrosion
3. Fuel hoses 8. Separator
Installation Note . ..., I .I,,,,I,I,.,.I.,,. page F-l 24 Inspect for cracks and corrosion
4. Evaporative hoses 9. Check valve (Two-way)
Installation Note ,..,..,................. page F-l 24 Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page F-140
5. Insulator 10. Check-and-cut valve
6. Fuel tank straps Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . page F-141
F--l 23

FUEL SYSTEM F
DIAGNOSI&ONNECTOR
03UOFX-138
I I 23UOFX-110
,
DISCONNECT CONNECTOR
REAR SEAT C
23UOFX-11
03UOFX-11

OBUOFX-11
FUEL PUMP
Inspection
Fuel pump operation
1, Connect the diagnosis connector terminals F/P and GND
with a jumper wire.
2. Remove the fuel filler cap.
3. Turn the ignition switch ON.
4. Listen for operational sound of the fuel pump at the filler inlet.
5. Install the fuel filler cap.
6. If no sound was heard, measure the voltage between the
fuel pump connector wire B/P to ground.
Specification: Battery voltage
7. If not correct, check the circuit opening relay and its cir-
cuits (Refer to page F-129.)
8. If the voltage is normal, check for continuity between fuel
pump connector B/P and B.
9. If there is continuity, replace the fuel pump.
IO. If there is no continuity, repair the ground circuit.
Hold pressure
Perform this inspection if the fuel pressure hold inspection is
not as specified. (Refer to page F-121 .)
Warning
l Before performing the following operation, release
the fuel pressure from the fuel system to reduce the
possibility of injury or fire. (Refer to page F-121 .)
1. Disconnect the negative battery terminal.
2. Connect a fuel pressure gauge to the fuel main pipe and
plug the outlet of the fuel pressure gauge as shown. (Install
clamps as shown.)
3. Connect the negative battery terminal.
4. Connect diagnosis connector terminals
F/P and GND with
a jumper wire.
5. Turn the ignition switch ON
for 10 sec. to operate the fuel
w-w.
6. Turn the ignition switch OFF and disconnect the jumper wire.
7. Observe the fuel pressure
after 5 min..
Fuel pressure:
More than 343 kPa (3.5 kg/cm’, 50 psi)
8. If not as specified, replace the fuel pump.
F-l 25

FUEL SYSTEM
Fuel pump maximum pressure
DISCONNECT CONNECTOR
TO RELEASE FUCL PRESSURE
Warning
23UOFX-11
OBUOFX-144 l
Before performing the following operation, release
the fuel pressure from the fuel system to reduce the
possibility of injury or fire. (Refer to page F-121 .) 4
1
2
23UOFX-15 7
1. Disconnect the negative battery terminal.
2. Connect a fuel pressure gauge to the fuel main pipe and
plug the outlet of the fuel pressure gauge as shown. (Install
clamps as shown.)
3. Connect the negative battery terminal.
4. Connect diagnosis connector terminals
F/P and GND with
a jumper wire.
5. Turn the ignition switch ON to operate the fuel pump.
6. Measure the pump maximum pressure.
Fuel pump maximum pressure:
441-637 kPa (4.5-6.5 kg/cm2, 64-92 psi) .--
7. Turn the ignition switch OFF and disconnect the jumper wire.
8. If not as specified, replace the fuel pump.
F-l 26