engine ISUZU KB P190 2007 Workshop Repair Manual

Fuel System – V6 Page 6C – 7

Fuel Flow
Fuel (A) is drawn into the modular fuel pump and sender
assembly reservoir from the fuel tank, through the primary
umbrella valve (5) and into the fuel pump impeller, via the
internal strainer (4) at the fuel pump (1) inlet. At the impeller,
vapour (C) is separated from the fuel. The vapour is ejected
from the fuel pump into the reservoir via a port next to the
fuel pump inlet.
High-pressure fuel then flows through the end cap, the lower
connector and the flexible line. From the flexible line, fuel
exits the modular fuel pump and sender assembly through
the fuel feed port and flows on to the externally-mounted
fuel filter and the engine.
A fuel pressure regulator is located in the modular fuel pump
and sender assembly; fuel not used by the engine (B) is
returned to the modular fuel pump and sender assembly via
the fuel return line and the fuel return port in the modular
fuel pump and sender assembly cover. The return fuel
enters the jet pump standpipe (3) of the reservoir via the
return fuel tube.
Vehicle fuel line pressure is maintained by a pressure
regulator (2) located within the modular fuel pump and
sender assembly.
W hen the engine is switched off, the reservoir remains full of
fuel, due to the action of the primary umbrella valve. At high
fuel levels, fuel tank overflow enters the reservoir over the
top of the reservoir. Fuel level in the reservoir is also
maintained by returned engine fuel.
Electrical power is supplied to the fuel pump by a connector
secured to the modular fuel pump and sender assembly
cover. An internal harness (not shown) assembly completes
the connection to the pump.
Figure 6C – 3


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Fuel System – V6 Page 6C – 8

3 System Checks
3.1 Fuel Pump Flow Test
If a reduction of the fuel supply is suspected, perform the following checks.
1 Ensure there is sufficient fuel in the tank.
2 W ith the engine running, check the fuel lines from the fuel tank to the injectors for evidence of leakage.
Retighten, if the lines or the connections are loose.
Also, check the fuel lines for restrictions such as
squashed or clogged fuel line.
3 Depressurize the fuel system, refer to 3.4 Fuel System Depressurisation.
4 Disconnect the fuel line at the fuel rail.
5 Connect a hose from the fuel line and place the open end into a clean container.
6 Connect the fuel pump relay terminals (2) with a jumper wire (1) as shown, then turn the ignition to the
ON position to operate the fuel pump, then check the
fuel pump flow rate.

Do not generate any sparks when connecting
the jumper wire.
Fuel delivery test time ....................................... 15.0 Sec
Fuel delivery rate .....................................0.38 Litres Min
NOTE
If the fuel flow rate is below the minimum value,
conduct a fuel pressure test, refer to 3.2
Fuel Pressure Test.
Figure 6C – 4

3.2 Fuel Pressure Test

To reduce the risk of fire or personal injury,
depressurise the fuel system before servicing
any fuel system components, refer to 3.4
Fuel System Depressurisation.
Gauge Installation
1 Turn the ignition switch off.
2 Depressurise the fuel system, refer to 3.4 Fuel System Depressurisation.

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Fuel System – V6 Page 6C – 9


A small amount of fuel may be released when
connecting the fuel pressure gauge to the fuel
pressure test point. Cover the fittings with a
shop towel to absorb any fuel spillage before
connecting the fuel pressure gauge. After the
fuel pressure test procedure, place the soiled
towel in an approved container for disposal.
3 At the fuel pressure test point, remove the Schrader valve sealing cap.
4 Connect the fuel pressure gauge (1) (tool No. J 34730–1A) to the fuel gauge Schrader fitting
adapter (2) (tool No. AU453), then install to the fuel
pressure test port (3). W rap a shop towel around the
fitting while connecting the fuel pressure gauge to
avoid and/or capture any fuel spillage.
5 Route the bleed hose of the fuel gauge into an approved fuel container.


Figure 6C – 5

After connecting the fuel pressure gauge and
pressurising the fuel system, inspect for fuel
leaks at the fuel pressure gauge and the fuel
pressure test point.
6 Either: Using Tech 2, enable the fuel pump to pressurise the fuel system, refer to 0C Tech 2. Inspect for fuel leaks at the
fuel pressure gauge and fuel pressure test point, then bleed the air from the fuel pressure gauge.
or: Reinstall the fuel pump relay and fuel pump fuse, then open the fuel gauge bleed valve (4) to bleed the air from the
fuel pressure gauge, refer to Figure 6C – 5.
7 Remove and place the soiled shop towel in an approved container.
Test
1 Start the engine and record the fuel pressure.
2 Turn the ignition switch off.
3 If required, perform any tests and/or diagnostic procedures:
• For the fuel system leak test, refer to 3.3 Fuel Leak Test.
• For the fuel injector leak-down test (for vehicles fitted with a V6 engine, refer to 6C1-3 Engine Management –
V6 – Service Operations.
4 Depressurise the fuel system, refer to 3.4 Fuel System Depressurisation.
Removal
1 Turn the ignition switch off.
2 Depressurise the fuel system, refer to 3.4 Fuel System Depressurisation.

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Fuel System – V6 Page 6C – 10


After relieving the fuel system pressure, a
small amount of fuel may be released when
servicing the fuel lines or connections. Cover
the fittings with a shop towel before
disconnecting. This catches any leaking fuel.
Place the soiled towel in an approved
container when disconnection is completed.
3 W rap a shop towel around the fuel pressure test point to absorb any fuel spillage.
4 Remove the fuel pressure gauge and drain any fuel remaining in the fuel pressure gauge into an approved fuel container.
5 Remove the soiled shop towel and place in an approved container.
6 Repressurise the fuel system, refer to 3.4 Fuel System Depressurisation.
7 Road-test the vehicle and check for correct operation.
3.3 Fuel Leak Test

After installing any fuel system component
and before starting the engine, check the fuel
system for leaks.
NOTE
For the fuel injector leak-down test (for vehicles
fitted with a V6 engine), refer to 6C1-3 Engine
Management – V6 – Service Operations.
1 Turn the ignition switch on for two seconds.
2 Turn the ignition switch off for 10 seconds.
3 Turn the ignition switch on.
4 Check for fuel leaks, particularly at points marked z (that is, quick-connect fittings, fuel rails, fuel injectors,
Schrader valve and evaporative emission control canister purge solenoid, refer to Figure 6C – 6.

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Fuel System – V6 Page 6C – 11


Figure 6C – 6
5 Replace any faulty components and repeat step 2 to step 5 inclusive.
6 Replace all engine components removed to perform the fuel leak test, refer to 6C1-3 Engine Management – V6 – Service Operations.
3.4 Fuel System Depressurisation

To reduce the risk of fire or personal injury,
depressurise the fuel system before servicing
any fuel system components.
1 Turn the ignition switch off.
2 Remove the fuel pump fuse and fuel pump relay, refer to 8A Electrical Body and Chassis.
3 Loosen the fuel filler cap to relieve the fuel tank vapour pressure.
4 W ith the throttle closed, crank the engine.
NOTE
The engine may start and operate until the fuel
remaining in the fuel delivery system depletes.
5 W hen the engine stops, crank the engine for another 10 seconds to ensure the fuel feed line pressure has been fully relieved.
6 Clean the area around the fuel pressure test point.

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Fuel System – V6 Page 6C – 12


A small amount of fuel may be released when
pressing on the Schrader valve. Cover the
fitting with a shop towel to absorb any fuel
spillage before removing the Schrader valve
sealing cap. Place the soiled towel in an
approved container for disposal.
7 At the fuel pressure test point (2), remove the Schrader valve sealing cap (1), refer to Figure 6C – 7.

Figure 6C – 7
Legend
1 Schrader Valve Sealing Cap
2 Pressure Test Point 3 Schrader Valve

Wear safety glasses when performing the fuel
pressure relief procedure.
8 Place a shop towel around the Schrader valve to soak up the expelled petrol.
9 Use a small screwdriver to press the Schrader valve down (3).
10 Remove the soiled shop towel and place in an approved container.
Repressurise
1 Reinstall the fuel pump relay and fuel pump fuse.
2 Perform the following procedure to inspect for leaks at the fuel pressure test point: a Turn the ignition switch on for two seconds.
b Turn the ignition switch off for 10 seconds.
c Turn the ignition switch on.
d Check for leaks at the fuel pressure test point.
3 Tighten the fuel filler cap.
4 Start the engine and recheck for leaks.
5 Reinstall the Schrader valve sealing cap.

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Fuel System – V6 Page 6C – 13

4 Service Operations
4.1 Fuel Lines And Quick Connect Fittings
Description
The fuel line connector fittings contain the following
components:
1 O-rings
2 Fuel line port
3 Connector
4 Plastic fuel line tube

Figure 6C – 8

Leak Test and Inspection
1. Turn the ignition key to the ON position and ensure the fuel pump runs for a short time by listening for the pump start up sound. The fuel pressure will increase when the fuel pump is actuated.
2 Perform a preliminary check of the system by inspecting the system for any leaks around the connections and fittings.
3 Perform steps 1 and 2 several times.
4 If the preliminary check of the system produces no leaks, start the engine and check the system again for any sign of leaks around the connections and lines.

Ensure all service precautions have been
observed prior to removing any connector
fittings.


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Fuel System – V6 Page 6C – 15

Reinstall
1 Apply a small amount of engine oil or light oil to the
fuel line to assist in the assembly of the connector.


NOTE
Assembly of the fuel line and quick connectors
should take place immediately after applying the
oil to prevent any dust from sticking to the
surface, which may cause the connector to leak.
Figure 6C – 12
4.2 Fuel Filter
Removal
1 Depressurize the fuel system, refer to 3.4 Fuel
System Depressurisation.
2 Disconnect the battery ground cable.

A small amount of fuel will flow out of the
fuel lines and filter when disconnected.
3 Locate the fuel filter attached to the front of the fuel tank, place a drain tray below the fuel filter and
remove the fuel line quick connectors from the inlet
(2) and the outlet (1) of the fuel filter, refer to 4.1 Fuel
Lines And Quick Connect Fittings.
Figure 6C – 13

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Fuel System – V6 Page 6C – 23

4.5 Modular Fuel Pump and Sender
Assembly
NOTE
If the modular fuel pump and sender assembly
develops a fault it must be replaced as a
complete unit. The only serviced parts are the
retainer locking ring and the O-ring seal.
Remove

• A depressurised fuel system contains fuel
in the fuel filter and fuel lines that can be
spilled during service operations.
• Fuel vapour remains in the fuel tank even
when completely empty. Seal all openings
in the fuel tank using suitable material or a
plastic plug. Ensure no naked flames or
other ignition sources are nearby. Ensure
all cellular phones (and transmission
devices that may cause any metal objects
to become unintentional receiving
antennas) are switched off.
• Place a dry chemical (Class B) fire
extinguisher nearby before performing any
on-vehicle service procedures. Failure to
follow these precautions may result in
personal injury.
• Wear safety glasses when using
compressed air. Do not blow compressed
air directly onto any body part.
1 Remove the fuel pump relay, refer to 8A Engine Body and Chassis.
2 Remove the fuel tank assembly from the vehicle, refer to 4.4 Fuel Tank.

Before proceeding, clean all traces of dirt and
other foreign material from the top of the fuel
tank, near the modular fuel pump and sender
assembly.
3 Use compressed air to ensure all dirt and foreign materials are removed from all fuel connections before disconnecting the parts.

Fuel can spill from the disconnected modular
fuel pump and sender assembly.

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Fuel System – V6 Page 6C – 36

Bell Housing Fuel Lines
1 Remove the bolt (1) securing the fuel line bracket to
the upper left-hand side of the bell housing, refer to
7B1 Transmission.

NOTE
The left-hand front exhaust pipe may need to be
moved aside to gain access to the fuel line
retaining bracket bolt (1), refer to 6F Exhaust
System – V6.
Fuel line bracket bolt
torque specification ...................................8.0 – 12.0 Nm
Figure 6C – 40

Engine Bay Fuel Lines
1 Remove the nut (5) from the fuel line bracket (4).
2 Unclip the fuel lines from the engine, refer to 4.1 Fuel
Lines And Quick Connect Fittings.
Figure 6C – 41

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