2004 ISUZU TF SERIES tow

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-117
CIRCUIT DESCRIPTION
When the ignition switch is turned “ON," the Engine
Control Module (ECM) will turn “ON" the in-tank fuel
pump. The in-tank fuel pump will remain “ON" as long
as the engine is cranking or running and the ECM is
receiving 58X crankshaft position pulses. If there are no
58X crankshaft position pulses, the ECM will turn the
in-tank fuel pump “OFF" 2 seconds after the ignition
switch is turned “ON" or 2 seconds after the engine
stops running.
The in-tank fuel pump is an electric pump within an
integral reservoir. The in-tank fuel pump supplies fuel
through an in-line fuel filter to the fuel rail assembly. The
fuel pump is designed to provide fuel at a pressure
above the pressure needed by the fuel injectors. A fuel
pressure regulator, attached to the fuel rail, keeps the
fuel available to the fuel injectors at a regulated
pressure. Unused fuel is returned to the fuel tank by a
separate fuel return line.
TEST DESCRIPTION
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. Connect the fuel pressure gauge to the fuel feed line
as shown in the fuel system illustration. Wrap a shop
towel around the fuel pressure connection in order to
absorb any fuel leakage that may occur when
installing the fuel pressure gauge. With the ignition
switch “ON" and the fuel pump running, the fuel
pressure indicated by the fuel pressure gauge
should be 333-376 kPa (3.4-3.8 kg/cm
2 / 48-55 psi).
This pressure is controlled by the amount o
f
pressure the spring inside the fuel pressure regulator
can provide.
3. A fuel system that cannot maintain a constant fuel
pressure has a leak in one or more of the following
areas:
 The fuel pump check valve.
 The fuel pump flex line.
 The valve or valve seat within the fuel pressure
regulator.
 The fuel injector(s).
4. Fuel pressure that drops off during acceleration,
cruise, or hard cornering may case a lean condition.
A lean condition can cause a loss of power, surging,
or misfire. A lean condition can be diagnosed using
a Tech 1 Tech 2. If an extremely lean condition
occurs, the oxygen sensor(s) will stop toggling. The
oxygen sensor output voltage(s) will drop below 500
mV. Also, the fuel injector pulse width will increase.

Important: Make sure the fuel system is not operating
in the “Fuel Cut-Off Mode."
When the engine is at idle, the manifold pressure is
low (high vacuum). This low pressure (high vacuum)
is applied to the fuel pressure regulator diaphragm.
The low pressure (high vacuum) will offset the
pressure being applied to the fuel pressure regulato
r
diaphragm by the spring inside the fuel pressure
regulator. When this happens, the result is lower fuel
pressure. The fuel pressure at idle will vary slightly
as the barometric pressure changes, but the fuel
pressure at idle should always be less than the fuel
pressure noted in step 2 with the engine “OFF."
16.Check the spark plug associated with a particula
r
fuel injector for fouling or saturation in order to
determine if that particular fuel injector is leaking. I
f
checking the spark plug associated with a particular
fuel injector for fouling or saturation does no
t
determine that a particular fuel injector is leaking,
use the following procedure:
 Remove the fuel rail, but leave the fuel lines and
injectors connected to the fuel rail. Refer to Fue
l
Rail Assembly in On-Vehicle Service.
 Lift the fuel rail just enough to leave the fuel
injector nozzles in the fuel injector ports.
CAUTION: In order to reduce the risk of fire and
personal injury that may result from fuel spraying
on the engine, verify that the fuel rail is positioned
over the fuel injector ports and verify that the fuel
injector retaining clips are intact.
 Pressurize the fuel system by connecting a 10
amp fused jumper between B+ and the fuel pump
relay connector.

Visually and physically inspect the fuel injector
nozzles for leaks.
17. A rich condition may result from the fuel pressure
being above 376 kPa (55 psi). A rich condition may
cause a DTC P0132 or a DTC P0172 to set.
Driveability conditions associated with rich conditions
can include hard starting (followed by black smoke)
and a strong sulfur smell in the exhaust.
20.This test determines if the high fuel pressure is due
to a restricted fuel return line or if the high fuel
pressure is due to a faulty fuel pressure regulator.
21.A lean condition may result from fuel pressure belo
w
333 kPa (48 psi). A lean condition may cause a DTC
P0131 or a DTC P0171 to set. Driveability conditions
associated with lean conditions can include hard
starting (when the engine is cold ), hesitation, poo
r
driveability, lack of power, surging , and misfiring.

6E-118 3.5L ENGINE DRIVEABILITY AND EMISSIONS
22.Restricting the fuel return line causes the fuel
pressure to rise above the regulated fuel pressure.
Command the fuel pump “ON" with the Tech 2. The
fuel pressure should rise above 376 kPa (55 psi) as
the fuel return line becomes partially closed.
NOTE: Do not allow the fuel pressure to exceed 414
kPa (60 psi). Fuel pressure in excess of 414 kPa (60
psi) may damage the fuel pressure regulator.
CAUTION: To reduce the risk of fire and personal
injury:
 It is necessary to relieve fuel system pressure
before connecting a fuel pressure gauge. Refer to
Fuel Pressure Relief Procedure, below.
 A small amount of fuel may be released when
disconnecting the fuel lines. Cover fuel line
fittings with a shop towel before disconnecting,
to catch any fuel that may leak out. Place the
towel in an approved container when the
disconnect is completed.
FUEL PRESSURE RELIEF PROCEDURE
1. Remove the fuel cap.
2. Remove the fuel pump relay from the underhood
relay center.
3. Start the engine and allow it to stall.
4. Crank the engine for an additional 3 seconds.
FUEL GAUGE INSTALLATION
1. Remove the fuel pressure fitting cap.
2. Install fuel gauge 5-8840-0378-0 to the fuel supply
line located in front of and above the right side valve
cover.
3. Reinstall the fuel pump relay.

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

6-12 ENGINE DIAGNOSIS (C24SE)
Engine Oil Consumption Excessive
Condition Possible cause Correction
Oil leaking Oil pan drain plug loose Retighten or replace gasket
Oil pan setting bolds loosened Retighten
Oil pan gasket broken Replace gasket
Front cover retaining bolts loose
or gasket broken Retighten or replace gasket
Head cover retaining bolts loose
or gasket broken Retighten or replace gasket
Oil filter adapter cracked Replace
Oil filter attaching bolt loose or
rubber gasket broken Retighten or replace oil filter
Crankshaft front or rear oil seal
defective Replace oil seal
Oil pressure unit loose or broken Retighten or replace
Blow-by gas hose broken Replace hose
Engine/Transmission coupling
area Replace oil seal
Oil leaking into combustion
chambers due to poor seal in
valve system Valve stem oil seal defective Replace
Valve stem or valve guide worn Replace valve and valve guide
Oil leaking into combustion
chambers due to poor seal in
cylinder parts Cylinders and pistons worn
excessively Rebore cylinder and replace
pistons and others
Piston ring gaps incorrectly
positioned Correct
Piston rings set with wrong side
up Correct
Piston rings sticking Rebore cylinder and replace
pistons and others
Piston ring and ring groove worn Replace pistons and others
Return ports in oil rings clogged Clean piston and replace rings
Crank case ventilation, Positive
Crankcase Ventilation System
malfunctioning Positive Crankcase Ventilation
Hose clogged Clean
Others Improper oil viscosity Use oil of recommended S.A.E.
viscosity
Continuous high speed driving
and or severe usage such as
trailer towing Continuous high speed operation
and or severe usage will normally
cause increased oil consumption

6A-12 ENGINE MECHANICAL (C24SE)
Engine - General C24SE
Fuel system Electronically controlled Multi Port Fuel Injection System
Fuel pump type Electric
Fuel pressure kg/cm2 (psi/Pa) 3.4 (48.4/334)
Fuel filter type Cartridge paper element
Air cleaner type Dry paper element
Battery Type/V-Ax No. of units 34B19L/50D20L
Alternator
Capacity V-A(W) 12-90 (1080), 12-100 (1200)
Starter
Output V-kW 1.4
Exhaust system CO Adjustment (1) Applicable to Open Loop System (Not equipped H2OS)
(2) Not applicable to Closed Loop System (Equipped H2OS)
Compression Ratio (with Tolerance) 9.6:10.25
Cylinder Head Material Aluminum Alloy (gravity cast)
Cylinder Block Material Cast Iron
No. of Mounting Points (including trans.) 3
Engine Installation Angles
-Longitudinal4 60'
-Lateral 7 50' (towards exhaust side)
Overall Dimensions (L




W




H):
- TF (2.4Litre/2WD) 610
564
708mm
- TF (2.4Litre/4WD) 610
564
746mm
Engine Weight
Engine Weight
- TF (2.4Liter/Man)140kg
Camshaft Type SOHC
No. of Valves per Cylinder
- Inlet1
- Exhaust 1
Spark Plug Location Side
Port Arrangement Cross Flow
Working Principle Spark Ignition 4-stroke

ENGINE MECHANICAL (C24SE) 6A-41


Installation
1. Install the cylinder head gasket.
Mark "OBEN/TOP" on top and turn it towards timing side
of engine.
2. Place cylinder head on cylinder block.

1
2
3


Installation
1. Insert the hydraulic valve lifters (3), thrust pieces (2) and
cam followers (1) with MoS2 paste.
Note allocation.
2. Apply a bead of Sealing Compound TB1207C to sealing
surface of cylinder head.
3. Install the camshaft housing on cylinder head.



Torque-Angle Method
Cylinder head and camshaft housing with new cylinder head
bolts to cylinder block.

Cylinder head bolts in sequence shown.



Installation
1. Install the rear toothed belt cover to camshaft housing.
2. Install the camshaft pulley to camshaft.
3. Install the camshaft housing cover to housing.




Installation
1. Install the toothed belt on camshaft pulley.
See operation "Timing Adjust".
2. Install the front toothed belt cover.

6A-72 ENGINE MECHANICAL (C24SE)
FUEL INJECTOR



Removal
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 fuel 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 fitting with a shop 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. Depressurize the fuel system.
2. Disconnect the fuel inlet.
3. Disconnect the fuel return line.
4. Remove the fuel rail from the intake manifold.
5. Remove the fuel injector from the fuel rail by disengaging
claws.

Installation
1. Install the fuel injector to the fuel rail by engaging claws.
2. Install the fuel rail to the intake manifold.
3. Connect the fuel return line firmly.
4. Connect the fuel supply line firmly.





Knock sensor
Removal
1. Remove fixing bolts.
2. Disconnect the connector at the other side.


Tighten (Torque)
Oxygen sensor in exhaust pipe - 30N

m (3.2 kgf

m)
When re-using, insert oxygen sensor.