fuel pump ISUZU TF SERIES 2004 Workshop Manual

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-119
Fuel System Diagnosis

Step Action Value(s) YES NO
1
Was the “On-Board Diagnostic (OBD) System Check"
performed? — Go to Step 2 Go to OBD
System Check
2
1. Turn the ignition “OFF."
2. Turn the air conditioning system “OFF."
3. Relieve fuel system pressure and install the fuel
pressure gauge.
Refer to 6E-118 FUEL GAUGE INSTALLATION
4. Turn the ignition “ON."
NOTE: The fuel pump will run for approximately 2
seconds. Use the Tech 2 to command the fuel
pump “ON".
5. Observe the fuel pressure indicated by the fuel
pressure gauge with the fuel pump running.
Is the fuel pressure within the specified limits? 290-376 kPa
(42-55 psi) Go to Step 3 Go to Step 17
3
The fuel pressure will drop when the fuel pump stops
running, then it should stabilize and remain constant.
Does the fuel pressure indicated by the fuel pressure
gauge remain constant? — Go to Step 4 Go to Step 12
4
1. When the vehicle is at normal operation
temperature, turn the ignition “ON" to build fuel
pressure and observe the measurement on the
gauge.
2. Start the engine and observe the fuel pressure
gauge.
Did the reading drop by the amount specified after the
engine was started? 21-105 kPa
(3-15 psi) Go to Step 5 Go to Step 9
5
Is fuel pressure dropping off during acceleration,
cruise, or hard cornering? — Go to Step 6 Check for
improper fuel
6 Visually and physically inspect the following items for
a restriction:
 The in-line fuel filter.
 The fuel feed line.
Was a restriction found? — Verify repair Go to Step 7
7 Remove the fuel tank and visually and physically
inspect the following items:
 The fuel pump strainer for a restriction.
 The fuel line for a leak.
 Verify that the correct fuel pump is in the vehicle.
Was a problem found in any of these areas? — Verify repair Go to Step 8

6E-120 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value(s) YES NO
8 Replace the fuel pump.
Is the action complete? — Verify repair —
9
1. Disconnect the vacuum hose from the fuel
pressure regulator.
2. With the engine idling, apply 12-14 inches of
vacuum to the fuel pressure regulator.
Does the fuel pressure indicated by the fuel pressure
gauge drop by the amount specified? 21-105 kPa
(3-15 psi) Go to Step 10 Go to Step 11
10 Locate and repair the loss of vacuum to the fuel
pressure regulator.
Is the action complete? — Verify repair —
11 Replace the fuel pressure regulator.
Is the action complete? — Verify repair —
12
1. Run the fuel pump with the Tech 2.
2. After pressure has built up, turn off the pump and
clamp the supply hose shut with suitable locking
pliers.
Does the fuel pressure indicated by the fuel pressure
gauge remain constant? — Go to Step 13 Go to Step 15
13 Visually inspect the fuel supply line and repair any
leaks.
Was a problem found? — Verify repair Go to Step 14
14 Remove the fuel tank and inspect for leaky hose or
in-tank fuel line.
Was a problem found? — Verify repair Go to Step 8
15
1. If the pliers are still clamped to the fuel supply
hose, remove the locking pliers.
2. With suitable locking pliers, clamp the fuel return
line to prevent fuel from returning to the fuel tank.
3. Run the fuel pump with the Tech 2.
4. After pressure has built up, remove power to the
pump.
Does the fuel pressure indicated by the fuel pressure
gauge remain constant? — Go to Step 11 Go to Step 16
16 Locate and replace any leaking fuel injector(s).
Is the action complete? — Verify repair —
17
Is the fuel pressure indicated by the fuel pressure
gauge above the specified limit? 376 kPa (55
psi) Go to Step 18 Go to Step 21

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-121
Step Action Value(s) YES NO
18
1. Relieve the fuel pressure. Refer to the Fuel
Pressure Relief.
2. Disconnect the fuel return line from the fuel rail.
3. Attach a length of flexible hose to the fuel rail
return outlet passage.
4. Place the open end of the flexible hose into an
approved gasoline container.
5. Run the fuel pump with the Tech 2.
6. Observe the fuel pressure indicated by the fuel
pressure gauge with the fuel pump running.
Is the fuel pressure within the specified limits? 290-376 kPa
(42-55 psi) Go to Step 19 Go to Step 20
19 Locate and correct the restriction in the fuel return
line.
Is the action complete? — Verify repair —
20 Visually and physically inspect the fuel rail outlet
passages for a restriction.
Was a restriction found? — Verify repair Go to Step 11
21
Is the fuel pressure indicated by the fuel pressure
gauge above the specified value? 0 kPa (0 psi) Go to Step 22 Go to Step 23
22
1. Command the fuel pump “ON" with the Tech 2.
2. Using suitable pliers which will not damage the fuel
hose, gradually apply pressure with the pliers to
pinch the flexible fuel return hose closed.
CAUTION: Do not let the fuel pressure exceed the
second specified value.
Does the fuel pressure indicated by the fuel pressure
gauge rise above the first specified value? 376 kPa (55
psi). 414 kPa
(60 psi). Go to Step 11 Go to Step 7
23
1. Command the fuel pump “ON" with the Tech 2.
2. Remove the fuel filler cap and listen for the sound
of the fuel pump running.
3. Turn the pump off.
Was the fuel pump running? — Go to Step 7 Go to Fuel
System
Electrical Test
Chart

6E-210 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
7
Repair the open or short to ground circuit between the
fuel pump relay and O2 sensor heater for the affected
cylinder.
Was the problem found?
- Verify repair Go to Step 8
8
Repair the open circuit between the O2 sensor heater
and engine ground for the affected cylinder.
Was the problem found?
- Verify repair Go to Step 9
9
Using the DVM and check the O2 sensor heater circuit
for the affected bank.
1. Ignition "Off", engine "Off".
2. Disconnect the O2 sensor connector for the
affected bank.
3. Check the circuit for short circuit.
Was the tester indicated specified value?
O2 Sensor BANK1/BANK2







Approximatly
16.5 at 20

Go to Step 12
Approximataly
0: Go to Step
10
No continuitly: Go
to Step 11
10
Repair the short circuit between the O2 sensor heater
power supply and ground circuit.
Is the action complete?
- Verify repair -
11
Replace the O2 sensor for the affected bank.
Was the problem solved?
- Verify repair Go to Step 12
12
Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the "SPS (Service Programming System)".
Was the problem solved?
- Verify repair Go to Step 13
13
Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual. Following
ECM programming, the immobilizer system (if
equipped) must be linked to the ECM. Refer to section
11 “Immobilizer System-ECM replacement” for the
ECM/Immobilizer linking procedure.
- Verify repair -

6E-222 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P1171 D Fuel Supply System
Lean During Power
Enrichment (Bank 1) 44

P1172 D Fuel Supply System
Lean During Power
Enrichment (Bank 2) 1. No DTC relating to MAF sensor, IAT sensor, ECT sensor,
TPS, CMP sensor, CKP sensor, VSS, injector control
circuit, ignition control circuit, O2 sensor circuit low voltage
& high voltage (bank 1 & 2) and O2 sensor circuit no
activity (bank 1 & 2).
2. Engine speed is between 1000rpm and 6000rpm.
3. Intake air temperature is below 70
C.
4. Engine coolant temperature is between 30
C and 120
C.
5. Engine load is between 150 and 255.
6. Throttle position output is more than 2.22V and fluctuation
is below 0.28V.
7. Except fuel cut operation.
8. O2 sensor output voltage below 250mV for 10 seconds. No fail-safe function.


CIRCUIT DESCRIPTION
The engine control module (ECM) internal circuitry can
identify if the vehicle fuel system is capable of supplying
adequate amounts of fuel during heavy acceleration
(power enrichment). The ECM monitors the voltage o
f
the oxygen sensor during power enrichment. When a
power enrichment mode of operation is requested
during “closed loop" operation (by heavy acceleration),
the ECM will provide more fuel to the engine. Unde
r
these conditions the ECM should detect a “rich"
condition (high oxygen sensor voltage). If this “rich"
exhaust is not detected at this time, a DTC P1171 o
r
P1172 will set. A plugged fuel filter, restricted fuel line,
restricted in-tank filter or defective fuel pump can
prevent adequate amouts of fuel from being supplied
during power enrichment mode.

DIAGNOSTIC AIDS
 A restricted fuel filter or fuel line, restricted in-tank
filter, or a defective fuel pomp may supply adequate
amounts of fuel at idle, but may not be able to supply
enough fuel during heavy acceleration.
 Water or alcohol in the fuel may cause low HO2S
voltage during acceleration.
 Check for faulty or plugged fuel injector(s).
 Check for low fuel.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-331
ENGINE CRANKS BUT WILL NOT RUN
DEFINITIONS: Engine cranks, but will not run. (The
engine never start.)
NOTE: The replacement ECM must be programmed.
Refer to section of the Service Programming
System (SPS) in this manual. Following ECM
programming, the immobilizer system (if equipped)
must be linked to the ECM. Refer to section 11
"Immobilizer System-ECM replacement" for the
ECM/Immobilizer linking procedure.
Should Tech2 display "SPS Procedure was not
successful", engine will not start, but no DTCs are
present, low battery voltage or poor electrical
connections should be the primary
suspects.Perform the SPS procedure again after
rectifying the fault/s.
NOTE: The vehicle with immobilizer system, this
system may be activated. Check the immobilizer
system diagnosis.


Step Action Value (s) Yes No
1
Was the "On-Board Diagnostic (OBD) System Check"
performed?
- Go to Step 2 Go to On Board
Diagnostic (OBD)
System Check
2
1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
- Verify repair Go to Step 3
3
Was a visually/physical check performed?
- Go to Step 4 Go to Visual /
physical Check
4
Check the "Meter" fuse (15A), "Engine" fuse (15A),
"IGN Coil" fuse (15A) and "Fuel Pump" fuse (20A). If
the fuse is burnt out, repair as necessary.
Was the problem found?
- Verify repair Go to Step 5
5
Check the ECM grounds to verify that they are clean
and tight. Refer to the ECM wiring diagrams.
Was a problem found?
- Verify repair Go to Step 6
6
Check the fuel quality.
Is the customer using proper fuel?
- Go to Step 7
Replace fuel
7
Visually/physically inspect for the following conditions:

Restrict air intake system. Check for a restricted air
filter element, or foreign objects blocking the air
intake system.

Check for objects blocking the IAC passage or
throttle bore, excessive deposits in the throttle bore
and on the throttle plate.

Check for a condition that causes a large vacuum
leak, such as an incorrectly installed or faulty
crankcase ventilation hose/brake booster hose.
Was a problem found?
- Verify repair Go to Step 8

6E-374 3.5L ENGINE DRIVEABILITY AND EMISSIONS
FUEL PRESSURE RELIEF
Caution:
To reduce the risk of the fire and personal injury, it
is necessary to relive the fuel system pressure
before servicing the fuel system components.
Caution:
After relieving the fuel system pressure, a small
amount of fuel may be released when servicing fuel
lines or connections. Reduce the chance o
f
personal injury by covering the fuel line fitting with
a short towel before disconnecting the fittings. The
towel will absorb any fuel that may leak out. When
the disconnect is completed, place the towel in an
approved container.

1. Remove the fuel filler cap.
2. Remove the fuel pump relay.
3. Start the engine and allow it to stall.
4. Crank the engine for about 30 seconds.
5. Disconnect the negative battery cable.



FUEL RAIL ASSEMBLY

Removal Procedure
NOTE:
 Do not attempt to remove the fuel inlet fitting on
the fuel rail. It is staked in place. Removing the
fuel inlet fitting will result in damage to the fuel
rail or the internal O-ring seal.
 Use care when removing the fuel rail assembly in
order to prevent damage to the injector electrical
connector terminals and the injector spray tips.
 Fittings should be capped and holes plugged
during servicing to prevent dirt and othe
r
contaminants from entering open lines and
passages.
Important: Before removal, the fuel rail assembly may
be cleaned with a spray type engine cleaner. Follow the
spray package instructions. Do not immerse the fuel
rails in liquid cleaning solvent.
1. Depressurize the fuel system. Refer to Fuel
Pressure Relief Procedure in this Section.
2. Disconnect the negative battery cable.
3. Remove the engine cover.
4. Disconnect the accelerator pedal cable from throttle
body and cable bracket.

5. Disconnect the connectors from, solenoid valve,
sensing valve.
6. Disconnect the vacuum hose on canister solenoid
and positive crankcase ventilation hose.
7. Remove the common chamber Refer to the
common chamber in Engine Mechanical.
1. Lift up carefully on the fuel injectors. Do no
t
separate the fuel injectors from the fuel rail.
2. If an injector becomes separated from the fuel
rail, the infector O-ring seals and the retaine
r
clip must be replaced.
3. Drain residual fuel into an approved container.




060RW044
8. If removal of the fuel pressure regulator is
necessary, refer to Fuel Pressure Regulator.
9. If removal of the fuel injectors is necessary, refer to
Fuel Injectors.

Installation Procedure
1. If the fuel injectors were removed, install them.
Refer to Fuel Injectors.
2. If the fuel pressure regulator was removed, install
it. Refer to Fuel Pressure Regulator.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-377
FUEL PRESSURE REGULATOR

Removal Procedure
CAUTION: To reduce the risk of fire and personal
injury, it is necessary to relieve the fuel system
pressure before servicing the fuel system
components.
CAUTION: After relieving the system pressure, a
small amount of fuel may be released when
servicing fuel lines or connections. Reduce the
chance of personal injury by covering the fuel line
fittings with a shop towel before disconnecting the
fittings. The towels will absorb any fuel that may
leak out. When the disconnect is completed, place
the towel in an approved container.
NOTE: Compressed air must never be used to test
or clean a fuel pressure regulator, as damage to the
fuel pressure regulator may result.
NOTE: To prevent damage to the fuel pressure
regulator, do not immerse the pressure regulator in
solvent.
1. Depressurize the fuel system. Refer to Fue
l
Pressure Relief Procedure.
2. Disconnect the negative battery cable.
3. Remove the fuel pump relay. Refer to Fuel Pump
Relay.
4. Remove the pressure regulator hose from the fuel
pressure regulator.
5. Remove the two bolts from the protector tha
t
secures the common chamber.



060RW066

6. Remove the fuel pressure regulator attaching
screw.




060RW116
7. Remove the fuel pressure regulator from the fuel
rail.

Disassembly Procedure
1. Remove the O-ring from the fuel pressure regulator.
2. Remove the fuel return line from the fuel pressure
regulator.
3. Remove the O-ring from the fuel return line.
 The O-ring may be left inside the fuel pressure
regulator instead of on the fuel return line.




060RW116

6E-378 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Assembly Procedure
1. Install a new O-ring on the fuel return line.
2. Install the fuel return line on the fuel pressure
regulator.
Do not over-tighten the swivel nut on the fuel pressure
regulator. The fuel pressure regulator can be damaged
and fuel may leak if the swivel nut is over-tightened.
3. Tighten the swivel nut.
4. Install a new O-ring on the fuel pressure regulator.

Installation Procedure
1. Install the fuel pressure regulator attaching screw.
Tighten
 Tighten the fuel pressure regulator attaching scre
w
to 3 Nm (0.3 kgm/26 lb in.).




060RW116
2. Install the fuel pressure regulator on the fuel rail.

3. Install the two bolts to the protector that secures
the common chamber.



060RW066
4. Install the pressure regulator hose to the fuel
pressure regulator.
5. Install the fuel pump relay. Refer to Fuel Pump
Relay.
6. Connect the negative battery cable.
7. Crank the engine until it starts. Cranking the engine
may take longer than usual due to trapped air in the
fuel lines.

ENGINE DIAGNOSIS (C24SE) 6-3
3.Trouble in Fuel System
Condition Possible cause Correction
Starting motor turns over and
spark occurs but engine does not
start. Fuel tank empty Fill
Water in fuel system Clean
Fuel filter clogged Replace filter
Fuel pipe clogged Clean or replace
Fuel pump defective Replace
Fuel pump circuit open Correct or replace
Evaporative Emission Control
system circuit clogged Correct or replace
Multiport Fuel Injection System
faulty Refer to "Electronic Fuel Injection"
section
4.Engine Lacks Compression
Condition Possible cause Correction
Engine lacks compression Spark plug loosely fitted or spark
plug gasket defective Tighten to specified torque or
replace gasket
Spark plug wire incorrect Connect properly or replace
Valve timing incorrect Adjust
Cylinder head gasket defective Replace gasket
Valve incorrectly seated Lap valve
Valve stem seized Replace valve and valve guide
Valve spring weakened Replace
Cylinder or piston rings worn Overhaul engine
Piston ring seized Overhaul engine.

Engine Compression Test Procedure
1. Start and run the engine until the engine
reaches normal operating temperature.
2. Turn the engine off.
3. Remove all the spark plugs.
4. Remove ignition coil fuse (15A) and disable the
ignition system.
5. Remove the fuel pump relay from the relay and
fuse box. 6. Engage the starter and check that the cranking
speed is approximately 300 rpm.
7. Install cylinder compression gauge into spark
plug hole.
8. With the throttle valve opened fully, keep the
starter engaged until the compression gauge
needle reaches the maximum level. Note the
reading.
9. Repeat the test with each cylinder.
The pressure difference between the individual
cylinders should not exceed 100kPa (14.5 psi).