2004 ISUZU TF SERIES engine

6E–270 ENGINE DRIVEABILITY AND EMISSIONS
FUEL PRESSURE RELIEF
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 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 from the underhood
relay box .
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:
Use care when removing the fuel rail assembly in
order to prevent damage to the injector al connector
terminal and the injector spray tips.
Fitting should be capped and holes plugged during
servicing to prevent dirt and other contaminants from
entering open lines and passage.
Important: An eight-digit identification number is
stamped on side of the fuel injector. Refer to this
number when you service the fuel rail or when a
replacement part is required.
1. Disconnect 4 injector connectors.
2. Lift side-clip up on the fuel rail.
3. Disconnect fuel pressure regulator hose.
4. Disconnect wiring harness from the bands on the
fuel rail.
5. Remove the intake pipe.
6. Loosen flare nut.
A. Lift up the injectors carefully to separate them
from intake manifold.
B. Lift up the fuel rail with injectors as assembly.
Do not separate the fuel injectors from fuel rail.
C. If an injector become separated from fuel rail,
injector backup O-ring and injector retainer clip
must be replaced.
D. Drain residual fuel from fuel rail into an
approved container.
7. If removal of fuel pressure regulator is necessary,
Refer to Fuel Pressure Regulator Removal
Procedure.

ENGINE DRIVEABILITY AND EMISSIONS 6E–271
8. If removal of fuel injector is necessary, Refer to Fuel
Injectors Removal Procedure.
Installation Procedure
1. Install the fuel injectors if necessary. Refer to Fuel
Injector Installation Procedure.
2. Install the fuel pressure regulator if necessary. Refer
to Fuel Pressure Regulator Installation Procedure.
3. Place the fuel injector rail assembly on the manifold
and insert the injectors into each port by pushing
fuel rail.
4. Install two fuel rail retaining bolts. Tighten fuel rail
retaining bolt to 19 N·m (1.9kgf·m)
5. Place wiring harness in its place and secure it with
two nuts.
6. Connect all connector to each fuel injector.
7. Connect the fuel supply line securely. Do not over
tighten.8. Connect the fuel return line securely. Do not over
tighten.
9. Connect the negative battery cable.
10. Crank the engine until it starts. Cranking the engine
may take longer than usual due to trapped air in the
fuel system. Check for leak. If fuel leak is observed,
stop engine immediately. Before correcting fuel
leak, be sure to depressurize system again.

6E–272 ENGINE DRIVEABILITY AND EMISSIONS
FUEL INJECTOR
Removal Procedure
NOTE: If the fuel injectors are leaking, the engine oil
may be contaminated with fuel. Check the oil for signs
of contamination and change the oil and filter if
necessary.
NOTE: Use care in removing the fuel injector in order to
prevent damage to the fuel injector al connector pins or
fuel injector nozzles. The fuel injector is an al
component and should not be immersed in any type of
cleaner as this may damage the fuel injector.
Important: Fuel injectors are serviced as complete
assembly only.
1. Disconnect the negative battery cable.
2. Disconnect al connector from fuel injector.
3. Remove the fuel rail. Refer to Fuel Rail Removal
Procedure.
4. Remove the fuel injector retainer clip.
5. Remove the fuel injector assembly from fuel rail.
6. Remove O-ring from the fuel injector.
7. Remove O-ring backup from fuel injector.Inspection
1. Inspect O-ring for crack, damage or leaks.
2. Replace worn or damaged O-ring.
3. Lubricate the new O-rings with engine oil before
installation.
Installation Procedure
1. Lubricate the new O-ring with engine oil.
2. Install the O-ring backup on the fuel injector.
3. Install new O-ring on the fuel injector.
4. Install all four injector on the fuel rail.
5. Use new injector retainer clip to retain the injetor to
the fuel rail.
6. Coat the end of the fuel injector with engine oil.

ENGINE DRIVEABILITY AND EMISSIONS 6E–273
7. Install fuel rail assembly. Tighten the nuts to 19 N·m
(1.9 kgf·m). Refer to Fuel Rail Installation
Procedure.
Tighten the flare nut to 27 - 33 N·m (2.8 - 3.4 kgf·m).
8. Connect the negative battery cable.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 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.
NOTE: Compressed air must never be used to test or
clean a fuel pressure regulator, as damage to the fuel
pressure regulator may occur.
NOTE: To prevent damage to the fuel pressure
regulator, do not immerse the pressure regulator in
solvent.
Removal Procedure
1. Depressurize the fuel system. Refer to Fuel
Pressure Relief Procedure.
2. Disconnect the negative battery cable.
3. Remove the fuel pump relay.
4. Disconnect the vacuum line form fuel pressure
regulator.

6E–274 ENGINE DRIVEABILITY AND EMISSIONS
5. Remove the fuel pressure regulator retaining screw.
6. Remove the fuel pressure regulator from fuel rail.
Installation Procedure
1. Insert the fuel pressure regulator into the fuel rail.2. Install the fuel pressure regulator retaining bracket
and tighten with a screw.
3. Connect vacuum line onto the fuel pressure
regulator.
4. Install the fuel pump relay.
5. Connect the negative battery cable.
6. Crank the engine until it starts. Cranking the engine
may take longer than usual due to trapped air in the
fuel line.
7. Tighten the flare nut to 27 - 33 N·m (2.8 - 3.4 kgf·m).

ENGINE DRIVEABILITY AND EMISSIONS 6E–275
IGNITION COIL
Location
Back of the engine right-hand side.
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the ignition coil connector.
3. Disconnect four spark plug cables from the ignition
coil.
4. Loosen three bolts and remove ignition coil from the
bracket.
Installation Procedure
1. Tighten the ignition coil by three bolts.
2. Connect four spark plug cables to the ignition coil.
3. Connect a ignition coil connector to the ignition coil.
4. Connect the negative battery cable.
NOTE: Verify any DTCs (diagnosis Trouble Code) are
not stored after replacement.
Verify proper connection of spark plug cables for each
cylinders.
SPARK PLUGS
Location
Installed on the left-hand side of cylinder head.
Removal Procedure
1. Disconnect the negative battery cable
2. Remove the spark plug cable.
3. Remove the spark plug.
Inspection
1. Check the insulator for cracks. Replace the spark
plug if cracks are present.
2. Check the electrode condition and replace the spark
plug if necessary.
If the spark plug electrodes and insulators are fouled
with carbon or oil, the engine will not operate efficiently.
There are a number of possible causes:
Fuel mix ture is too rich.

6E–276 ENGINE DRIVEABILITY AND EMISSIONS
Oil in the combustion chamber.
The spark plug gap is not set correctly.
If spark plug fouling is ex cessive, check the fuel and al
system for possible causes of trouble. If fuel and al
system are normal, install spark plugs of a higher heat
range which have the same physical dimensions as the
original equipment spark plugs.
The following symptoms are characteristics of spark
plugs that are running too hot:
Fuel mixture is too lean.
Heat range is incorrect.
If vehicle usage does not conform to normal driving
conditions, a more suitable spark plug may be
substituted.
If fuel and al system are normal, in most cases of this
sort, the problem can be corrected by using a colder
type spark plug with the same physical dimensions as
the original equipment spark plug.
3. Check the gaskets for damage and replace if
necessary.
4. Measure the spark plug gap. The specification is 1.0
to 1.1mm (0.039 to 0.043").
5. Adjust the spark gap by bending the grounded
electrode.Installation
1. Tighten the spark plug to the 25N·m (2.5kgf·m).
2. Push the spark plug cable in until it snaps in.
Installation Procedure
1. Install the spark plug to the cylinder head.
2. Tighten the spark plug with specified tightening
torque.
Tightening Torque
Bolt: 25N·m (2.5kgf·m)
3. Connect the spark plug cable to the spark plug.
4. Connect the negative battery cable.
NOTE: Verify any DTCs (diagnosis Trouble Code) are
not stored after replacement.
Verify proper connection of spark plug cables for each
cylinders.

ENGINE DRIVEABILITY AND EMISSIONS 6E–277
SPARK PLUG CABLES
The cable contains a synthetic conductor which is easily
damaged. Never stretch or kink the cable. Disconnect
the cable from spark plug and the ignition coil.
The original equipment cables and the ignition coil are
marked to show correct location of the cables. If spark
plug cables or the ignition coil are replaced previously,
before cables are removed from the ignition coil, mark
the cables and the coil so they can be reconnected in
the same position.
Inspection
NOTE: Never puncture the spark plug cable’s insulation
with a needle or the pointed end of a probe into the
cable. An increase in resistance would be created which
would cause the cable to become defective.
1. If the cable has broken or cracked insulation, it must
be replaced.
2. If the terminals are corroded or loose, the cable
must be replaced.
3. Check that the cable resistance does not ex ceed
specified value.
#1 cylinder: 3.50k
- 5.24k

#2 cylinder: 2.89k
- 4.33k

#3 cylinder: 2.49k
- 3.73k

#4 cylinder: 2.22k
- 3.32k

EMISSION CONTROL ;




CO ADJUSTER (W/
O CATALYSTIC CONVERTER)
CO : Carbon monox ide
Location
Under the leht-hand side of the front sheet.
Removal Procedure
1. Remove the left-hand side of the front sheet. Refer
to Sec.10 CAB “Front Sheet”.
2. Disconnect the CO adjuster connector.
3. Remove the CO adjuster.
Installation Procedure
1. Connect the CO adjuster connector.
2. Install the left-hand side of the front sheet. Refer to
Sec.10 CAB “Front Sheet”.
3. Check and adjust CO concentration.
Checking procedure
1. Operate the engine at normal temperature.
2. Turn all accessories switch OFF.
3. Place the select lever in the “N” range.
4. Start the engine at idle.