fuel pressure ISUZU AXIOM 2002 Service User Guide

6A±10
ENGINE MECHANICAL (6VE1 3.5L)
Engine Lacks Power
ConditionPossible causeCorrection
Trouble in fuel systemFuel Pressure Control Valve not
working normallyReplace
Fuel injector cloggedClean or replace
Fuel pipe cloggedClean
Fuel filter clogged or fouledReplace
Fuel pump drive circuit not working
normallyCorrect or replace
Fuel tank not sufficiently breathing
due to clogged Evaporative
Emission Control System circuitClean or replace
Water in fuel systemClean
Inferior quality fuel in fuel systemUse fuel of specified octane rating
Powertrain Control Module supplied
poor voltageCorrect circuit
Throttle Position Sensor cable
broken or poor connectionsCorrect or replace
Throttle Position Sensor defectiveReplace
Mass Airflow Sensor not working
normallyReplace
Manifold Absolute Pressure Sensor
not working normallyReplace
Intake Air Temperature Sensor not
working normallyReplace
Engine Coolant Temperature Sensor
circuit open or shortedCorrect or replace
Engine Coolant Temperature Sensor
defectiveReplace
Powertrain Control Module defectiveReplace
Trouble in intake or exhaust systemAir Cleaner Filter cloggedReplace filter element
Air duct kinked or flattenedCorrect or replace
TWC defectiveRepair
Ignition failureÐÐÐÐRefer to Hard Start Troubleshooting
Guide
Heat range of spark plug inadequateInstall spark plugs of adequate heat
range
Ignition coil defectiveReplace

6A±14
ENGINE MECHANICAL (6VE1 3.5L)
Abnormal Combustion
ConditionPossible causeCorrection
Trouble in fuel systemFuel pressure control valve defectiveReplace
Fuel filter cloggedReplace
Fuel pump cloggedClean or replace
Fuel tank or fuel pipe cloggedClean or replace
Fuel injector cloggedClean or replace
Fuel pump relay defectiveReplace
Power supply cable for fuel pump
broken or poor connectionsReconnect, correct or replace
Mass Airflow (MAF) Sensor circuit
open or defectiveCorrect or replace
MAF Sensor defectiveReplace
Manifold Absolute Pressure Sensor
circuit open or shortedCorrect or replace
Manifold Absolute Pressure Sensor
defectiveReplace
Engine Coolant Temperature (ECT)
Sensor circuit open or shortedCorrect or replace
ECT Sensor defectiveReplace
Throttle Position Sensor adjustment
incorrectReadjust
Throttle Position Sensor defectiveReplace
Throttle Position Sensor connector
poor connectionsReconnect
Vehicle Speed Sensor cable poor
connections or defectiveCorrect or replace
Vehicle Speed Sensor loosely fixedFix tightly
Vehicle Speed Sensor in wrong
contact or defectiveReplace
Powertrain Control Module cable
poor connections or defectiveCorrect or replace
Trouble in emission control systemHeated Oxygen Sensor circuit openCorrect or replace
Heated Oxygen Sensor defectiveReplace
Signal vacuum hose loosely fitted or
defectiveCorrect or replace
EGR Valve circuit open or shortedCorrect or replace
Exhaust Gas Recirculation Valve
defectiveReplace
ECT Sensor circuit open or shortedCorrect or replace
Canister Purge Valve circuit open or
shortedCorrect or replace
Canister Purge Valve defectiveReplace
ECT Sensor defectiveReplace
Positive Crankcase Ventilation
(PCV) valve and hose cloggedCorrect or replace
Evaporator systemRefer to Section 6E
Trouble in ignition systemÐÐÐÐRefer to ªEngine Lacks Powerº

6A±17
ENGINE MECHANICAL (6VE1 3.5L)
Fuel Consumption Excessive
ConditionPossible causeCorrection
Trouble in fuel systemMixture too rich or too lean due to
trouble in fuel injection systemRefer to ªAbnormal Combustionº
Fuel cut function does not workRefer to ªAbnormal Combustionº
Trouble in ignition systemMisfiring or abnormal combustion
due to trouble in ignition systemRefer to ªHard Startº or ªAbnormal
Combustionº
OthersEngine idle speed too highReset Idle Air Control Valve
Fuel system leakageCorrect or replace
Clutch slippingCorrect
Brake dragCorrect
Selection of transmission gear
incorrectCaution operator of incorrect gear
selection
Excessive Exhaust Gas
Recirculation flow due to trouble in
Exhaust Gas Recirculation systemRefer to ªAbnormal Combustionº
Lubrication Problems
ConditionPossible causeCorrection
Oil pressure too lowWrong oil in useReplace with correct engine oil
Relief valve stickingReplace
Oil pump not operating properlyCorrect or replace
Oil pump strainer cloggedClean or replace strainer
Oil pump wornReplace
Oil pressure gauge defectiveCorrect or replace
Crankshaft bearing or connecting
rod bearing wornReplace
Oil contaminationWrong oil in useReplace with correct engine oil
Oil filter cloggedReplace oil filter
Cylinder head gasket damageReplace gasket
Burned gases leakingReplace piston and piston rings or
cylinder body assembly
Oil not reaching valve systemOil passage in cylinder head or
cylinder body cloggedClean or correct
Engine Oil Pressure Check
1. Check for dirt, gasoline or water in the engine oil.
a. Check the viscosity of the oil.
b. Check the viscosity of the oil.
c. Change the oil if the viscosity is outside the
specified standard.
d. Refer to the ªMaintenance and Lubricationº section
of this manual.
2. Check the engine oil level.
The level should fall somewhere between the ªADDº
and the ªFULLº marks on the oil level dipstick.
If the oil level does not reach the ªADDº mark on the
oil level dipstick, engine oil must be added.3. Remove the oil pressure unit.
4. Install an oil pressure gauge.
5. Start the engine and allow the engine to reach normal
operating temperature (About 80
C).
6. Measure the oil pressure.
Oil pressure should be:
392±550 kPa (56.9±80.4 psi) at 3000 rpm.
7. Stop the engine.
8. Remove the oil pressure gauge.
9. Install the oil pressure unit.
10. Start the engine and check for leaks.

6A±18
ENGINE MECHANICAL (6VE1 3.5L)
Malfunction Indicator Lamp
The instrument panel ªCHECK ENGINEº Malfunction In-
dicator Lamp (MIL) illuminates by self diagnostic system
when the system checks the starting of engine, or senses
malfunctions.
Condition
Possible causeCorrection
ªCHECK ENGINEº MIL does not
illuminate at the starting of engine
Bulb defectiveReplace
illuminate at the starting of engineMIL circuit openCorrect or replace
Command signal circuit to operate
self diagnostic system shortedCorrect or replace
Powertrain Control Module (PCM)
cable loosely connected,
disconnected or defectiveCorrect or replace
PCM defectiveReplace
ªCHECK ENGINEº MIL illuminates,
and stays onDeterioration of heated oxygen
sensor internal elementReplace
Heated oxygen sensor connector
terminal improper contactReconnect properly
Heated oxygen sensor lead wire
shortedCorrect
Heated oxygen sensor circuit openCorrect or replace
Deterioration of engine coolant
temperature sensor internal elementReplace
Engine coolant temperature sensor
connector terminal improper contactReconnect properly
Engine coolant temperature sensor
lead wire shortedCorrect
Engine coolant temperature sensor
circuit openCorrect or replace
Throttle position sensor open or
shorted circuitsCorrect or replace
Deterioration of crankshaft position
sensorReplace
Crankshaft position sensor circuit
open or shortedCorrect or replace
Vehicle speed sensor circuit openCorrect or replace
Manifold absolute pressure sensor
circuit open or shortedCorrect or replace
Intake air temperature sensor circuit
open or shortedCorrect or replace
Fuel injector circuit open or shortedCorrect or replace
PCM driver transistor defectiveReplace PCM
Malfunctioning of PCM RAM
(Random Access Memory) or ROM
(Read Only Memory)Replace PCM

6A±22
ENGINE MECHANICAL (6VE1 3.5L)
Common Chamber
Removal
1. Disconnect battery ground cable.
2. Remove air cleaner duct assembly.
013RY00001
Legend
(1) Positive Crankcase Ventilation Hose Connector
(2) Intake Air Temperature Sensor
(3) Air Cleaner Duct Assembly
(4) Air Flow Sensor
3. Disconnect vacuum booster hose from common
chamber.
4. Disconnect connector from manifold absolute
pressure sensor, Ion sensing module, throttle
position sensor, solenoid valve, electric vacuum
sensing valve, and EGR valve.
5. Disconnect vacuum hose on canister VSV and
positive crankcase ventilation hose, fuel rail
assembly with pressure control valve bracket.
6. Remove ventilation hose from throttle valve and
intake duct and remove water hose.
7. Remove the four throttle body fixing bolts.
8. Remove exhaust gas recirculation valve assembly
fixing bolt and nut on common chamber and remove
EGR valve assembly.9. Remove two bolts from common chamber rear side
to remove fuel hose bracket.
10. Remove common chamber four bolts and four nuts
then remove the common chamber.
025RY002
Legend
(1) Common Chamber
(2) Throttle Valve Assembly
(3) Bolt
Installation
1. Install common chamber and tighten bolts and nuts to
the specified torque.
Torque :
Bolt : 25 N´m (18 lb ft)
Nut : 25 N´m (18 lb ft)
2. Install fuel hose bracket and tighten bolts to specified
torque.
Torque : 10 N´m (87 lb in)
3. Install exhaust gas recirculation valve assembly and
tighten bolt and nut to the specified torque.
Torque : 25 N´m (18 lb ft)
4. Install throttle body and tighten bolts to the specified
torque.
Torque : 25 N´m (18 lb ft)
5. Install ventilating hose to throttle valve and intake
duct.
6. Connect vacuum hoses on canister VSV and positive
crankcase ventilation hose. Tighten bolts for fuel rail
assembly with pressure control valve bracket.
Torque : 25 N´m (18 lb ft)

6A±46
ENGINE MECHANICAL (6VE1 3.5L)
Engine Assembly
Removal
035R200001
1. Disconnect battery ground and positive cable.
2. Remove battery.
3. Make alignment mark on the engine hood and hinges
before removal in order to return the hood to original
position exactly.
4. Remove engine hood.
5. Drain radiator coolant.
6. Disconnect Ion sensing module harness connectors,
and manifold absolute pressure sensor harness
connectors from sensor on common chamber.
7. Disconnect throttle position sensor harness
connectors from throttle body.
8. Disconnect air duct with air cleaner cover.
9. Remove air cleaner assembly.
10. Disconnect canister vacuum hose.
11. Disconnect vacuum booster hose.
12. Disconnect three engine harness connectors.
13. Disconnect harness connector to transmission (left
front side of engine compartment), disconnect shift
on the fly harness connector from front side of front
axle and remove transmission harness bracket from
engine left side.
14. Disconnect ground cable between engine and frame.
15. Disconnect bonding cable connector on the back of
right dash panel.
16. Disconnect bonding cable terminal on the left bank.
17. Disconnect starter harness connector from starter.
18. Disconnect generator harness connector from
generator.
19. Disconnect coolant reserve tank hose from radiator.
20. Remove radiator upper and lower hoses.21. Remove upper fan shroud.
22. Remove cooling fan assembly four fixing nuts, then
the cooling fan assembly.
23. Move drive belt tensioner to loose side using wrench
then remove drive belt.
24. Remove power steering pump fixing bolts, then
power steering pump. Place the power steering pump
along with piping on the body side.
25. Remove air conditioning compressor fixing bolts from
bracket and place the compressor along with piping
on the body side.
26. Remove four O
2 sensor harness connectors (two
each bank) from exhaust front pipe.
27. Remove three exhaust pipe fixing nuts from each
bank.
28. Remove two exhaust pipe fixing nuts from each
exhaust pipe, then move exhaust pipe to rear side of
vehicle.
29. Remove flywheel dust covers.
30. Disconnect two heater hoses from engine.
31. Disconnect fuel hoses from right side of transmission.
CAUTION: Plug fuel pipes on engine side and fuel
hoses from fuel tank.
32. Remove transmission assembly. Refer to
Transmission section in this manual.
33. Support the engine by engine hoist.
34. Remove two left side engine mount fixing bolts from
engine mount on chassis side.
35. Remove two right side engine mount fixing bolts from
engine mount on chassis side.
36. Remove engine assembly.

6C±2
ENGINE FUEL (6VE1 3.5L)
General Description
140R200004
Legend
(1) Fuel Filler Cap
(2) Fuel Tank
(3) Rollover Valve
(4) Fuel Pump and Sender Assembly
(5) Fuel Filter
(6) Fuel Rail Right
(7) Right Bank
(8) Fuel Rail Left
(9) Left Bank(10) Fuel Pressure Control Valve
(11) Common Chamber
(12) Duty Solenoid Valve
(13) Throttle Valve
(14) Canister
(15) Vent Hose
(16) Vent Solenoid Valve
(17) Separator
(18) Shut off Valve (With Over Pressure Relief
Valve)

6C±3 ENGINE FUEL (6VE1 3.5L)
When working on the fuel system, there are several
things to keep in mind:

Any time the fuel system is being worked on,
disconnect the battery ground cable except for those
tests where battery voltage is required.

Always keep a dry chemical (Class B) fire
extinguisher near the work area.

Replace all pipes with the same pipe and fittings that
were removed.

Clean and inspect ªOº rings. Replace if required.

Always relieve the line pressure before servicing any
fuel system components.

Do not attempt repairs on the fuel system until you
have read the instructions and checked the pictures
relating to that repair.

Adhere to all Notices and Cautions.
All gasoline engines are designed to use only unleaded
gasoline. Unleaded gasoline must be used for proper
emission control system operation.
Its use will also minimize spark plug fouling and extend
engine oil life. Using leaded gasoline can damage the
emission control system and could result in loss of
emission warranty coverage.
The vapor pressure sensor and vent solenoid valve for
vapor pressure sensor are used to detect abnormalities in
the evaporative emission control system.
The PCM decides whether there is an abnormality in the
evaporative emission control system based on vapor
pressure sensor signal.Fuel Metering
The Powertrain Control Module (PCM) is in complete
control of this fuel delivery system during normal driving
conditions.
The intake manifold function, like that of a diesel, is used
only to let air into the engine. The fuel is injected by
separate injectors that are mounted over the intake
manifold.
The Manifold Absolute Pressure (MAP) sensor measures
the changes in the intake manifold pressure which result
from engine load and speed changes, which the MAP
sensor converts to a voltage output.
This sensor generates the voltage to change
corresponding to the flow of the air drawn into the engine.
The changing voltage is transformed into an electric
signal and provided to the PCM.
With receipt of the signals sent from the MAP sensor,
Intake Air Temperature sensor and others, the PCM
determines an appropriate fuel injection pulse width
feeding such information to the fuel injector valves to
affect an appropriate air/fuel ratio.
The Multiport Fuel Injection system utilizes an injection
system where the injectors turn on at every crankshaft
revolution. The PCM controls the injector on time so that
the correct amount of fuel is metered depending on
driving conditions.
Two interchangeable ªOº rings are used on the injector
that must be replaced when the injectors are removed.
The fuel rail is attached to the top of the intake manifold
and supplies fuel to all the injectors.
Fuel is recirculated through the rail continually while the
engine is running. This removes air and vapors from the
fuel as well as keeping the fuel cool during hot weather
operation.
The fuel pressure control valve that is mounted on the fuel
rail maintains a pressure differential across the injectors
under all operating conditions. It is accomplished by
controlling the amount of fuel that is recirculated back to
the fuel tank based on engine demand.
See Section ªDriveability and Emissionº for more
information and diagnosis.

6C±5 ENGINE FUEL (6VE1 3.5L)
Installation
1. Install the fuel filter in the proper direction.
2. Install fuel filter holder fixing bolt.
3. Connect fuel hoses on engine side(1) and fuel tank
side(2).
041RW001
4. Install fuel filler cap
5. Connect the battery ground cable.
Inspection
After installation, start engine and check for fuel leakage.
In±Tank Fuel Filter
The filter is located on the lower end of fuel pickup tube in
the fuel tank. The fuel filter prevents dirt and water the fuel
system not unless the filter is submerged in water. The
fuel filter is maintenance free, that requires no
maintenance. Excess water and sediment in the tank
restricts fuel supply to the engine, resulting in engine stall.
If this happens, the fuel tank would need to be cleaned
thoroughly.
Fuel Pump Flow Test
If reduction of fuel supply is suspected, perform the
following checks.
1. Make sure that there is fuel in the tank.
2. With the engine running, check the fuel feed pipe and
hose from fuel tank to injector for evidence of
leakage. Retighten, if pipe or hose connection is
loose. Also, inspect bent or kink fuel pipes and hoses.
3. Insert the hose from fuel feed pipe into a clean
container, and check for fuel pump flow rate.
4. Connect the pump relay terminals with a jumper
wire(1) as shown and start the fuel pump to measure
delivery.
140R200003
CAUTION: Never generate sparks when connecting
a jumper wire.
Delivery Times
Delivery
15 seconds0.38 liters minimum
If the measure value is out of standard, conduct the
pressure test.
Pressure test
For the pressure test to the fuel system, see Section 6E
ªFuel Control Systemº.

6C±6
ENGINE FUEL (6VE1 3.5L)
Fuel Pump
Fuel Pump and Associated Parts
140R200008
Legend
(1) Fuel Feed Port
(2) Fuel Tube/Quick Connector
(3) Fuel Return Port
(4) Fuel Pump and Sender (FPS) Assembly(5) Connector; Fuel Feed Pump
(6) Connector; Fuel Tank Pressure Sensor
(7) Retainer (Fuel Pump Lock)
(8) Fuel Tank Assembly
(9) Seal; Fuel Pump
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 ªDriveability and Emissionº.
1. Remove fuel tank assembly(8). Refer to ªFuel Tank
Removalº in this section.
2. Remove Fuel Tube/Quick Connector (2).
NOTE: Refer to ªFuel Tube/Quick Connector Fittingsº in
this section when performing any repairs.