fuel ISUZU TF SERIES 2004 Workshop Manual

ENGINE FUEL (C24SE) 6C-3


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 "O" 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.

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.



Service Precaution
CAUTION:
Always use the correct fastener in the proper location.
When you replace a fastener, use ONLY the exact part
number for that application. ISUZU will call out those
fasteners that require a replacement after removal. ISUZU
will also call out the fasteners that require thread lockers
or thread sealant. UNLESS OTHERWISE SPECIFIED, do
not use supplemental coatings (Paints, greases, or othe
r
corrosion inhibitors) on threaded fasteners or fastene
r
joint interfaces. Generally, such coatings adversely affect
the fastener torque and the joint clamping force, and may
damage the fastener. When you install fasteners, use the
correct tightening sequence and specifications. Following
these instructions can help you avoid damage to parts
and systems.

6C-4 ENGINE FUEL (C24SE)

Fuel Metering
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 senso
r
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 o
f
fuel is metered depending on driving conditions.
Two interchangeable "O" rings are used on the injector tha
t
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 "Driveability and Emission" for more information
and diagnosis.

ENGINE FUEL (C24SE) 6C-5
Fuel Filter
Fuel Filter and Associated Parts







Removal
CAUTION: When repair to the fuel system has been
completed, start engine and check the fuel system fo
r
loose connections or leakage. For the fuel system
diagnosis, see Section "Driveability and Emissions".

(2.4L)
1. Disconnect battery ground cable.
2. Disconnect the quick connector from the fuel filter.
3. Pull off fuel filter from the holder to side member side.
4. Remove the fuel filter.

6C-6 ENGINE FUEL (C24SE)
Fuel Filter
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 o
r
sediment.
Installation
1. Install the filter to holder from side member side.
NOTE: Attend direction of fuel filter. (1) to engine side
(2) to fuel tank side.
NOTE: Verify to hang holder hook to fuel filter.


NOTE: Verify to hang holder hook to fuel filter.




RTW36CSH000301
2. Connect the quick connector from the fuel tube to
the fuel filter.
NOTE: Pull of the left checker into the fuel pipe.
NOTE: Refer to “Fuel Tube/Quick Connector Fittings” in
this section when performing any repairs.
3. Tighten fuel filler cap until at least one click are
heard.
4. 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 selfcleaning type, no
t
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.

ENGINE FUEL (C24SE) 6C-7
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 o
f
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 (2) with a
jumper wire (1) as shown and start the fuel pump
to measure delivery.




RTW36CSH000201
CAUTION: Never generate sparks when connecting
a jumper wire.

Delivery Delivery
15 seconds 0.38 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
“Fuel Control System".

6C-8 ENGINE FUEL (C24SE)
Fuel Pump
Fuel Pump and Associated Parts



RTW46FMF000401
Legend (6) Fuel Tube/Quick Connector
(1) Fuel Feed Port (7) Retainer Ring (Fuel Pump Lock)
(2) Fuel Return Port (8) Seal; Fuel Pump
(3) Fuel Emission Port (9) Fuel Tank Assembly
(4) Fuel Pump and Sender Assembly (10) Evapo Tube/Quick Connector
(5) Connector; Fuel Feed Pump & Sender

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 “Driveability and Emission".
1. Remove fuel tank assembly (9). Refer to “Fuel
Tank Removal" in this section.
2. Disconnect the quick connector (6) into the fuel
tube from fuel pump.
3. Disconnect the quick connector (10) into the evapo
tube from fuel pump.

ENGINE FUEL (C24SE) 6C-9
3. Remove the retainer ring (7) from the fuel tank
with the removal tool 5-8840-2602-0.




140R100035
4. Remove slowly the fuel pump (4) from the fuel
tank as no bend float arm.
NOTE: Cover opening for the fuel pump on fuel tank to
prevent any dust enthering.
5. Discard fuel pump seal (8) because it cannot be
reusable.
Installation
1. Clean the seal surface of the fuel tank and the fuel
pump.
NOTE: If there is dust on the seal surface, it becomes
cause of fuel leak.
2. Install the new fuel pump seal (8) to opening of the
fuel tank as along the groove.
3. Install slowly the fuel pump (4) into the fuel tank as
no bend float arm.
4. Set flange of the fuel pump on fuel pump seal as
mating convexity of the fuel pump and reentrant o
f
the fuel tank.
5. Lock slowly the retainer ring (7) to the fuel tank
with the remover tool 5-8840-2602-0.
6. Connector the quick conector (10) into the evapo
tube to fuel pump.
7. Connect the quick connector (6) into the fuel tube
to fuel pump.
NOTE: Pull off the left ckecker into the fuel pipe.
NOTE: Refer to “Fuel Tube/Quick Connector Fittings” in
this section when performing any repairs.

8. Check leak.
Methed of leak check.
(1) Plug end of quick connector and breather hose
(Pull off the breather hose from fuel tank) and
tighten fuel filler cap until at least one click are
heard.
(2) Apply water soap around the fuel pump seal
area.
(3) Pressure air into the fuel tank from end o
f
breather pipe at 5psi (34.3 kPa/2.8kgf/cm2)
over 15 seconds.
(4) Verify no bubbles around the fuel pump seal
area.
8. Install the fuel tank assembly (9).
NOTE: Refer to “Install the fuel tank” in this section.

6C-10 ENGINE FUEL (C24SE)
Fuel Tube / Quick – Connector Fittings
Precautions
 Do not light a match or create a flame.
 Keep flames away from your work area to preven
t
flammable materials from catching fire.
 Disconnect battery ground cable to preven
t
electrical shorts.
 Pre-treat piping system or associated parts from
thermal damage or from spattering when welding
or similar heat-generating work.
Cautions During Work




140R100032
Legend
(1) O-ring
(2) Port
(3) Connector
(4) Plastic Tube

Do not expose the assembly to battery electrolyte or do
not wipe the assembly with a cloth used to wipe off spil
t
battery electorolyte.
Piping that has been splattered with battery electrolyte
or battery electrolyte soaked cloth that was wiped on the
piping cannot be used.
Removal
1. Open the fuel cap to relieve the fuel pressure in the
tank.
Use compressed air to remove any dirt on the fuel
quick connect fittings prior to disconnecting the
fittings.




141R100002
When disconnecting the fuel pipe, cover the area
with a cloth to prevent fuel from splashing as the
fuel pipe may still have some pressure in it.
2. For removal of the quick connector, hold the quick
connector in one hand, and pull out the connento
r
with the other hand while pressing the square
relieve button of the connector, as illustrated.






140R100037
NOTE: Do not use tools of any kind. Only use bare
hands when disconnecting the connector. Use a
lubricant (light oil) and/or push and pull the connecto
r
until the pipe is disconnected.
Cover the connectors that was removed with a
plastic bag, to prevent dust or rain water from
entering.

ENGINE FUEL (C24SE) 6C-11




140R100028
Reuse of Quick–Connector
 Replace the port and connector if scratch, dent or
crack is found.
 Remove any dirt build up on the port when installing
the connector. Replace the connector, if there is any
forms of rust, dent, scratch.

After cleaning the port, insert it straight into the
connector until it clicks. After it clicks, try pulling a
t
49N (5kgf) it out to make sure that it is not drawn
and is securely locked.




140R100036

Assembling Advice
By applying engine oil or light oil to the pipe, port makes
pipe assembly easier. The pipe assembly should take
place immediately after applying oil (to prevent dus
t
from sticking to the pipe surface –which may
decrease sealing ability).
Test/Inspection After Assembling
1. Reconnect the battery negative cable.
2. Turn the ignition key to the “ON" position and listen
for pump start-up sound. Inspect for leaks, the
fuel pressure will increase as the fuel pump is
actuated.
3. Perform leak inspection (step 2) several times.
4. Start the engine and observe the engine idle speed.
The presence of dirt in the fuel system may affec
t
the fuel injection system.

6C-12 ENGINE FUEL (C24SE)
Fuel Pump Relay
General Description
In order to control the fuel pump and sender assembly
(FPAS) operation, the FPAS relay is provided. When
the starter switch is turned to “ON" position, the FPAS
relay operates the FPAS for 2 seconds.
When it is turned to “START" position, the Engine
Control Module receives the reference pulse from the
Ignition Control Module and it operates the relay, again
causing the FPAS to feed fuel.