engine ISUZU TROOPER 1998 Service Repair Manual

6C±2
ENGINE FUEL
General Description
140RW030
Legend
(1) Fuel Filler Cap
(2) Fuel Tank
(3) Rollover Valve
(4) Fuel Pump
(5) Fuel Filter
(6) Fuel Rail Right
(7) Right Bank(8) Fuel Rail Left
(9) Left Bank
(10) Fuel Pressure Control Valve
(11) Common Chamber
(12) Duty Solenoid Valve
(13) Throttle Valve
(14) Canister
When working on the fuel system, there are several
things to keep in mind:

Any time the fuel system is being worked on,
disconnect the negative battery cable except for
those tests where battery voltage is required.

Always keep a dry chemical (Class B) fire
extinguisher near the work area.
Replace all pipes with the same pipe and fittings that
were removed.

Clean and inspect ªOº rings. Replace if required.

Always relieve the line pressure before servicing any
fuel system components.

Do not attempt repairs on the fuel system until you
have read the instructions and checked the pictures
relating to that repair.

6C±3
ENGINE FUEL

Adhere to all Notices and Cautions.
All gasoline engines are designed to use only unleaded
gasoline. Unleaded gasoline must be used for proper
emission control system operation.
Its use will also minimize spark plug fouling and extend
engine oil life. Using leaded gasoline can damage the
emission control system and could result in loss of
emission warranty coverage.
All cars are equipped with an Evaporative Emission
Control System. The purpose of the system is to minimize
the escape of fuel vapors to the atmosphere.
Fuel Metering
The Engine Control Module (ECM) is in complete control
of this fuel delivery system during normal driving
conditions.
The intake manifold function, like that of a diesel, is used
only to let air into the engine. The fuel is injected by
separate injectors that are mounted over the intake
manifold.
The Manifold Absolute Pressure (MAP) sensor measures
the changes in the intake manifold pressure which result
from engine load and speed changes, which the MAP
sensor converts to a voltage output.
This sensor generates the voltage to change
corresponding to the flow of the air drawn into the engine.
The changing voltage is transformed into an electric
signal and provided to the ECM.
With receipt of the signals sent from the MAP sensor,
Intake Air Temperature sensor and others, the ECM
determines an appropriate fuel injection pulse width
feeding such information to the fuel injector valves to
effect an appropriate air/fuel ratio.
The Multiport Fuel Injection system utilizes an injection
system where the injectors turn on at every crankshaft
revolution. The ECM controls the injector on time so that
the correct amount of fuel is metered depending on
driving conditions.
Two interchangeable ªOº rings are used on the injector
that must be replaced when the injectors are removed.
The fuel rail is attached to the top of the intake manifold
and supplies fuel to all the injectors.
Fuel is recirculated through the rail continually while the
engine is running. This removes air and vapors from the
fuel as well as keeping the fuel cool during hot weather
operation.
The fuel pressure control valve that is mounted on the fuel
rail maintains a pressure differential across the injectors
under all operating conditions. It is accomplished by
controlling the amount of fuel that is recirculated back to
the fuel tank based on engine demand.
See Section ªDriveability and Emissionº for more
information and diagnosis.

6C±4
ENGINE FUEL
Fuel Filter
Fuel Filter and Associated Parts
041RW014
Legend
(1) Fuel Filler Cap
(2) Fuel Hose(3) Fuel Filter Fixing Bolt
(4) Fuel Filter
Removal
CAUTION: When repair to the fuel system has been
completed, start engine and check the fuel system
for loose connection or leakage. For the fuel system
diagnosis, see Section ªDriveability and Emissionº.
1. Disconnect battery ground cable.
2. Remove Fuel filler cap(1).
3. Disconnect fuel hoses(2) from fuel filter on both
engine side and fuel tank side.
4. Fuel filter fixing bolt(3).

Remove the fuel filter fixing bolt(3) on fuel filter
holder.
5. Remove fuel filter(4).
Inspection
1. Replace the fuel filter if the fuel leaks from fuel filter
body or if the fuel filter body itself is damaged.
2. Replace the filter if it is clogged with dirt or sediment.
3. Check the drain of receive rubber and if it is clogged
with dust, clean it up with air.

6C±5
ENGINE FUEL
Installation
1. Install the fuel filter in the proper direction.
2. Install fuel filter holder fixing bolt.
3. Connect fuel hoses on engine side(1) and fuel tank
side(2).
041RW001
4. Install fuel filler cap
5. Connect the battery ground cable.
Inspection
After installation, start engine and check for fuel leakage.
In±Tank Fuel Filter
The filter is located on the lower end of fuel pickup tube in
the fuel tank. It prevents dirt from entering the fuel pipe
and also stops water unless the filter is completely
submerged in the water. It is a self cleaning type, not
requiring scheduled maintenance. Excess water and
sediment in the tank restricts fuel supply to the engine,
resulting in engine stoppage. In such a case, the tank
must be cleaned thoroughly.
Fuel Pump Flow Test
If reduction of fuel supply is suspected, perform the
following checks:
1. Make sure that there is fuel in the tank.
2. With the engine running, check the fuel feed pipe and
hose from fuel tank to injector for evidence of
leakage. Retighten, if pipe or hose connection is
loose. Also, check pipes and hoses for squashing or
clogging.
3. Insert the hose from fuel feed pipe into a clean
container, and check for fuel pump flow rate.4. Connect the pump relay terminals with a jumper
wire(1) as shown and start the fuel pump to measure
delivery.
140RW002
CAUTION: Never generate sparks when connecting
a jumper wire.
Delivery
Delivery
15 seconds0.38 liters minimum
If the measure value is out of standard, conduct the
pressure test.
Pressure test
For the pressure test to the fuel system, see Section 6E
ªFuel Control Systemº.

6C±6
ENGINE FUEL
Fuel Pump
Fuel Pump and Associated Parts
035RW047
Removal
CAUTION: When repair to the fuel system has been
completed, start engine and check the fuel system
for loose connection or leakage. For the fuel system
diagnosis, see Section ªDriveability and Emissionº.
1. Disconnect battery ground cable.
2. Loosen fuel filler cap.
3. Drain fuel.
Tighten drain plug to the specified torque after
draining fuel.
Torque: 20 N´m (2.0 Kg´m/14 lb ft) Ð M8
4. Remove fuel tank assembly(1). Refer to ªFuel Tank
Removalº in this section.
5. Remove fuel pump (FP) assembly(2) fixing screws
and remove the FP assembly.
NOTE: After removing FP, cover fuel tank to prevent any
dust entering.
Installation
1. Install FP assembly(2).
2. Install fuel tank assembly(1). Refer to ªFuel Tank
Installationº.
3. Fill the tank with fuel and tighten fuel filler cap.
4. Connect battery ground cable.

6C±7
ENGINE FUEL
Fuel Pump Relay
General Description
In order to control the FP operation, the FP relay is
provided. When the starter switch is turned to ªONº
position, the FP relay operates the FP for 2 seconds.When it is turned to ªSTARTº position, the Power Train
Control Module (PCM) receives the reference pulse from
the Ignition Control Module and it operates the relay,
again causing the FP to feed fuel.
Fuel Tank
Fuel Tank and Associated Parts
035RW048
Legend
(1) Fender Liner
(2) Fuel Filler Hose and Air Breather Hose and
Evapo Hose
(3) Undercover(4) Fuel Tank Wiring Connector
(5) Evapo Fuel Hose
(6) Fuel Feed Tube and Fuel Return
Tube/Quick±Connect Fittings
(7) Fuel Tank
Removal
CAUTION: When repair to the fuel system has been
completed, start engine and check the fuel system
for loose connection or leakage. For the fuel system
diagnosis, see Section ªDriveability and Emissionº.
1. Disconnect battery ground cable.
2. Loosen fuel filler cap.3. Drain fuel.
Tighten drain plug to the specified torque after
draining fuel.
Torque: 20 N´m (2.0 Kg´m/14 lb ft) Ð M8
4. Remove fender liner (1) of wheel well on rear right
side.
5. Fuel filler hose, air breather hose and evapo hose (2).
6. Remove undercover fixing bolts on both sides and
remove under cover(3).

6C±8
ENGINE FUEL
7. Disconnect two fuel tank wiring connectors(4) on
front right side of tank.
8. Disconnect evapo fuel hose(5).
9. Disconnect fuel feed tube and fuel return tube(6).
NOTE: Handling of the fuel tube, be sure to refer ªFuel
Tube/Quick±Connect Fittingsº in this section.
10. Remove fuel tank fixing bolts on both sides and
remove fuel tank(7).
Installation
1. Install fuel tank(7).

Place a flange on right side of tank on the bracket.
Install a flange on left side on the bracket from the
bottom, and tighten bolts to the specified torque.
Torque: 36 N´m (3.7 Kg´m/27 lb ft)
2. Connect fuel feed tube and fuel return tube(6).
3. Connect evapo fuel hose(5).
4. Connect fuel tank wiring connector(4).
5. Install undercover(3).
6. Connect fuel filler hose, air breather hose and evapo
hose(2).
7. Install fender liner(1).

Mount fender liner to the wheel well.

Fill the tank with fuel and tighten fuel filler cap.

Connect battery ground cable.
Fuel Tube / Quick ± Connect Fittings
Precautions

Lighting of Fires Prohibited.

Keep flames away from your work area to prevent the
inflammable from catching fire.

Disconnect the battery negative cable to prevent
shorting during work.

When welding or conducting other heat-generating
work on other parts, be sure to provide pretreatment
to protect the piping system from thermal damage or
spattering.
Cautions During Work
Do not expose the assembly to battery electrolyte or do
not wipe the assembly with a cloth used to wipe off spilt
battery electorolyte.
The piping wet with battery electrolyte cannot be used.
Be careful not to give a bending or twisting force to the
piping during the work. If deformed, replace with a new
piping.
Removal
1. Open the fuel cap to relieve the fuel pressure in the
tank.
If the fuel quick-connect fittings are dusty, clean with
an air blower, etc. and then remove it.
141RW016As some pressure may remain in the piping, cover the
connector with a cloth, etc. to prevent the splashing
of fuel in the first disconnection of the piping.

6C±9
ENGINE FUEL
2. For removal of the delivery pipe (feeding fuel to the
engine), hold the connector in one hand, and hold the
retainer tab with the other hand and pull out the
connector, as illustrated. The pipe can be removed
with the retainer attached.
141RW019
3. For removal of the return pipe (returning fuel to the
tank), hold the pipe in one hand, and pull out the
connentor with the other hand while pressing the
square relieve button of the retainer, as illustrated.
141RW020
NOTE: This work should be done by hands. Do not use
any tools. Should the pipe can hardly be removed from
the connector, use a lubricant (light oil) and/or push and
pull the connector longitudinally until the pipe is removed.
141RW021When reusing the delivery pipe retainer, reuse
without removing the retainer from the pipe. If the
retainer is damaged or deformed, however, replace
with a new retainer.
Cover the connectors removed with a plastic bag, etc.
to prevent the entry of dust or rain water.
141RW022

6C±10
ENGINE FUEL
Reuse of Quick±Connector
(Delivery Pipe)

Replace the pipe and connector if scratch, dent or
crack is found.

Remove mud and dust from the pipe and make sure
that the end including spool is free of defects, such as
scratch, rust, and dent, which may cause poor
sealability. If defective, replace with a new pipe.

If the retainer removed according to the removal step
above is attached to the pipe, clean and insert it
straight into the quick-connector till it clicks. After it
clicks, try pulling it out to make sure that it is not drawn
and is securely locked.
NOTE: The retainer, once removed from the pipe, cannot
be reused. Just replace with a new retainer. Insert the
new retainer into the connector side until it clicks, and
connect the pipe as inserting it into the retainer until it
clicks.
141RW018
(Return Pipe)

Replace the pipe and connector if scratch, dent or
crack is found.

Remove mud or dust from the pipe and make sure
that the end including spool is free from defects, such
as scratch, rust, and dent, which may cause poor
sealability. If defective, replace with a new pipe.

After cleaning the pipe, insert it straight into the
connector until it clicks. After it clicks, try pulling it out
to make sure that it is not drawn and is securely
locked.
141RW017
Assembling Advice
Application of engine oil or light oil to the pipe facilitates
connecting work. The work should be started immediately
after lubrication, since dust may stick to the pipe surface
to cause poor sealability if a long time passes after
lubrication.
Test/Inspection After Assembling
1. Reconnect the battery negative cable.
2. Turn the ignition key to the ªONº position and check
pump startup sound. As the pump is actuated to raise
fuel pressure, check and see fuel leak from the piping
system.
3. Make sure of no fuel leakage by conducting the above
fuel leak check a few times.
4. Start the engine and make sure of stable idling speed
and normal vehicle run.The entry of dust during the
work may sometimes affect the fuel injection system.

6C±11
ENGINE FUEL
Fuel Gauge Unit
Fuel Gauge Unit and Associated Parts
140RS004
Legend
(1) Wiring Connector
(2) Fuel Gauge Unit
Removal
CAUTION: When repair to the fuel system has been
completed, start engine and check the fuel system
for loose connection or leakage. For the fuel system
diagnosis, see Section ªDriveability and Emissionº.
1. Disconnect battery ground cable.
2. Loosen fuel filler cap.
3. Drain fuel.
Tighten drain plug to the specified torque after
draining fuel.
Torque: 20 N´m (2.0 Kg´m/14 lb ft) Ð M8
4. Wiring connector

Disconnect wiring connector(1) from the unit.
5. Fuel gauge unit

Remove the fixing screws, then the fuel gauge
unit(2).
NOTE: After removing fuel gauge unit, cover fuel tank to
prevent any dust entering
Installation
1. Fuel gauge unit(2).
2. Wiring connector(1).

Connect the wiring connector to the fuel gauge unit.

Fill the tank with fuel and tighten fuel filler cap.

Connect battery ground cable.