2004 ISUZU TF SERIES fuel cap

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.

6C-14 ENGINE FUEL (C24SE)
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. Disconnect battery ground cable.
2. Loosen slowly the fuel filler cap.
NOTE: To prevent spouting out fuel to change the
pressure in the fuel tank.
NOTE: Cover opening of the filler neck to prevent any
dust entering.
3. Jack up the vehicle.
4. Support underneath of the fuel tank with a lifter.
5. Remove the inner liner of the wheel house on rea
r
left side.
6. Remove fasten bolt to the filler neck from the
body.
7. Disconnect the quick connector (8) into the fuel
tube from the fuel pipe and the evapo tube from
evapo joint connector.
NOTE: Cover the quick connector to prevent any dus
t
entering and fuel leaking.
NOTE: Refer to “Fuel Tube/Quick Connector Fittings” in
this section when performing any repairs.
8. Remove fasten bolt (1) to the tank band and the
tank band (2).
9. Disconnect the pump and sender connector on the
fuel pump and remove the harness from weld clip
on the fuel tank.
10. Lower the fuel tank (6).
NOTE: When the fuel tank is lowered from the vehicle,
don’t scratch each hose and tube by around other pars.


Installation
1. Rise the fuel tank into position.
NOTE: Ensure hoses and tubes do not foul on othe
r
component.
2. Connect the pump and sender connector to the
fuel pump and install harness to into the plastic clip
welded to the top of the fuel tank..
NOTE: The connector must be certainly connected
against stopper.
Ensure tank band anchor mates with guide hole on
frame.
3. Install the tank band to fasten bolt.
Torque: 68 N




m (6.9kg




m/50 lb ft)
NOTE: The anchor of the tank band must be certainly
installed to guide hole on frame.
4. Connect the quick connector from the fuel tube to
the fuel pipe and the evapo tube from evapo join
t
connector.
NOTE: Pull off the left checker into the fuel pipe.
NOTE: Refer to “Fuel Tube/Quick Connector Fittings” in
this section when performing any repairs.
5. Install the filler neck to the body by bolt.
6. Install the inner liner of the wheel house on rea
r
side.
7. Remove lifter to support underneath of the fuel
tank.
8. Put back the vehicle.
9. Tigten the filler cap until at least three clicks are
heard.
10. Connect the battery ground cable.

6C-16 ENGINE FUEL (C24SE)
Fuel Filler Cap
General Description
A vacuum valve and pressure valve are built into the
fuel filler cap which adjusts the fuel pressure in the fuel
tank to prevent fuel tank damage.



RTW36CSH000401
Legend
(1) Pressure Valve
(2) Vacuum Valve
(3) Seal Ring

Inspection
The fuel filler cap must be inspected for seal condition.
The fuel filler cap must be replaced if found defective
CAUTION: A replacement fuel filler cap must be the
same as the original. The fuel filler cap valve was
designed primarily for this application and must be
replaced with the same type or decreased engine
performance may occur.

ENGINE DRIVEABILITY AND EMISSIONS 6E–57
GENERAL DESCRIPTION FOR
EVAPORATIVE EMISSION SYSTEM
EVAP Emission Control System Purpose
The basic evaporative emission control system used on
the charcoal canister storage method. The method
transfers fuel vapor from the fuel tank to an activated
carbon (charcoal) storage devise to hold the vapors
when the vehicle is not operating.
The canister is located on the rear ax le housing by the
frame cross-member.
When the engine is running, the fuel vapor is purged
from the carbon element by intake air flow and
consumed in the normal combustion process.
EVAP Emission Control System Operation
The EVAP canister purge is controlled by a solenoid
valve that allows the manifold vacuum to purge the
canister. The engine control module (ECM) supplies a
ground to energize the solenoid valve (purge on). The
EVAP purge solenoid control is pulse-width modulated
(PWM) (turned on and off several times a second). The
duty cycle (pulse width) is determined by engine
operating conditions including load, throttle position,
coolant temperature and ambient temperature. The duty
cycle is calculated by the ECM. the output is
commanded when the appropriate conditions have
been met. These conditions are:
The engine is fully warmed up.
The engine has been running for a specified time.
The IAT reading is above 10°C (50°F).
Purge/Vacuum Hoses. Made of rubber compounds,
these hoses route the gasoline fumes from their
sources to the canister and from the canister to the
intake air flow.
EVAP Canister. Mounted on a bracket ahead of the
fuel tank, the canister stores fuel vapors until the
ECM determined that engine conditions are right for
them to be removed and burned.
Poor idle, stalling and Poor driveability can be caused
by:
A malfunctioning purge solenoid.
A damaged canister.
Hoses that are split, cracked, or not connected
properly.
System Fault Detection
The EVAP leak detection strategy is based on applying
vacuum to the EVAP system and monitoring vacuum
decay. At an appropriate time, the EVAP purge solenoid
is turned “ON,” allowing the engine vacuum to draw a
small vacuum on the entire evaporative emission
system.
After the desired vacuum level has been achieved, the
EVAP purge solenoid is turned “OFF,” sealing the
system. A leak is detected by monitoring for a decrease
in vacuum level over a given time period, all other
variables remaining constant.
If the desired vacuum level cannot be achieved in the
test described above, a large leak or a faulty EVAP
purge control solenoid valve is indicated.
Leaks can be caused by the following conditions:
Missing or faulty fuel cap
Disconnected, damaged, pinched, or blocked EVAP
purge line
Disconnected, damaged, pinched, or blocked fuel
tank vapor line
Disconnected or faulty EVAP purge control solenoid
valve
Open ignition feed circuit to the purge solenoid (1) Purge Solenoid Valve
(2) From Canistor to Purge Solenoid
(3) From Purge Solenoid to Intake
(1) Canistor
(2) Air Separator
132
12

ENGINE DRIVEABILITY AND EMISSIONS 6E–59
POSITIVE CRANKCASE VENTILATION
(PCV) SYSTEM
Crankcase Ventilation System Purpose
The crankcase ventilation system is used to consume
crankcase vapors in the combustion process instead of
venting them to the atmosphere. Fresh air from the
throttle body is supplied to the crankcase and mixed
with blow-by gases. This mix ture is then passed through
the positive crankcase ventilation (PCV) port into the
intake manifold.
While the engine is running, ex haust gases and small
amounts of the fuel/air mix ture escape past the piston
rings and enter the crankcase. these gases are mixed
with clean air entering through a tube from the air intake
duct.
During normal, part-throttle operation, the system is
designed to allow crankcase gases to flow through the
PCV hose into the intake manifold to be consumed by
normal combustion.
A plugged positive crankcase ventilation port or PCV
hose may cause the following conditions:
Rough idle.
Stalling or slow idle speed.
Oil leaks.
Sludge in the engine.
A leaking PCV hose would cause:
Rough idle.
Stalling.
High idle speed.

6E–104 ENGINE DRIVEABILITY AND EMISSIONS
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 alow it to stall.
4. Crank the engine for an additional 3 seconds.
Fuel Pressure Gauge Installation
1. Remove the fuel pressure fitting cap.
2. Install fuel pressure gauge 5-8840-0378-0 to the
fuel feed line located in front of and above the right
side valve cover.
3. Reinstall the fuel pump relay.
Fuel System Electrical Test
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go to On Board
Diagnostic
(OBD) System
Check
2 1. Using the Tech 2, ignition “On” and engine “On”.
2. Select the “Miscellaneous Test” and perform the
“Fuel Pump Relay” in the “Relays”.
3. Operate the Tech 2 in accordance with procedure.
Was the fuel pump operated, when the Tech 2 is
operated?—Go to Fuel
System
DiagnosisGo to Step 3
3 Check the “Fuel Pump” fuse (20A).
If the fuse is burnt out, repair as necessary.
Was the problem found?—Verify repair Go to Step 4
4 Check for poor/faulty connection at the fuel pump, fuel
pump relay or ECM connector. If a poor/faulty
connection is found, repair as necessary.
Was the problem found?
—Verify repair Go to Step 5
5 Using the DVM and check the fuel pump relay.
1. Ignition “Off”, engine “Off”.
2. Remove the fuel pump relay from the relay box .
3. Check the relay coil.
Was the DVM indicated specified value?
120 - 150
Go to Step 6Replace fuel
pump relay and
verify repair
11C56(J2)
F2 X2
Fuel Pump Relay

 




ENGINE DRIVEABILITY AND EMISSIONS 6E–109
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 2 Scan Tool.
Following are applicable to the vehicle with
closed Loop System:
If an ex tremely lean condition occurs, the ox ygen
sensor(s) will stop toggling. The ox ygen 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 regulator
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 particular
fuel injector for fouling or saturation in order to
determine if that particular fuel injector is leaking. If
checking the spark plug associated with a particular
fuel injector for fouling or saturation does not
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 Fuel
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 20
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 45 to set. Driveability conditions associatedwith rich conditions can include hard starting
(followed by black smoke) and a strong sulfur smell
in the ex haust.
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 below
333 kPa (48 psi). A lean condition may cause a 44 to
set. Driveability conditions associated with lean
conditions can include hard starting (when the
engine is cold), hesitation, poor driveability, lack of
power, surging, and misfiring.
22.Restricting the fuel return line causes the fuel
pressure to rise above the regulated fuel pressure.
Command the fuel pump ON with the scan tool. 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. Located on the intake manifold which is at the top
right part of the engine.
3. Start the engine and allow it to stall.
4. Crank the engine for an additional 3 seconds.
Fuel Pressure Gauge Installation
1. Remove the fuel pressure fitting cap.
2. Install fuel pressure gauge 5-8840-0378-0 to the
fuel feed line located on the upper right side of the
engine.
3. Reinstall the fuel pump relay.