engine coolant ISUZU TF SERIES 2004 Repair Manual

6A-6 ENGINE MECHANICAL (6VE1 3.5L)
Rough Engine Idling or Engine Stalling
Symptom Possible Cause Action
Trouble in fuel injection system Idle air control valve defective Replace
Throttle shutting off incomplete Replace
Throttle position sensor circuit open
or shorted Correct or replace
Fuel injector circuits open or shortedCorrect or replace
Fuel injectors damaged Replace
Fuel pump relay defective Replace
Mass Airflow Sensor circuit open or
poor connections Correct or replace
Mass Airflow Sensor defective Replace
Engine Coolant Temperature Sensor
circuit open or poor connections Correct or replace
Engine Coolant Temperature Sensor
defective Replace
Intake Air Temperature sensor circuit
open or poor connections Correct or replace
Intake Air Temperature sensor
defective Replace
Vehicle Speed Sensor circuit open or
shorted Correct or replace
Vehicle Speed Sensor defective Replace
Trouble in emission control system EGR valve defective Replace
EGR valve circuit open or poor
connection Correct or replace
Engine Control Module defective Replace
Canister purge valve circuit open or
poor connections Correct or replace
Canister purge valve defective Replace
Evaporative Emission Canister Purge
control valve defective Replace
Trouble in ignition system Refer to “Hard Start"
Others Engine lacks compression Refer to “Hard Start"
Valve incorrectly seated Lap valve
Air Cleaner Filter clogged Replace filter element
Valve timing incorrect Readjust
Idle air control valve broken Replace
Fast idle solenoid defective Replace
Positive Crankcase Ventilation valve
defective or clogged Replace

ENGINE MECHANICAL (6VE1 3.5L) 6A-7
Rough Engine Running
Symptom Possible Cause Action
Engine misfires periodically Ignition coil layer shorted Replace
Spark plugs fouling Clean or install hotter type plug
Spark plug(s) insulator nose leaking Replace
Fuel injector(s) defective Replace
Engine control module faulty Replace
Engine knocks periodically Spark plugs running too hot Install colder type spark plugs
Engine control module faulty Replace
Engine lacks power Spark plugs fouled Clean
Fuel injectors defective Replace
Mass Airflow Sensor or Intake Airflow
Sensor circuit defective Correct or replace
Engine Coolant Temperature Sensor
or Engine Coolant Temperature
Sensor circuit defective Correct or replace
Engine Control Module faulty Replace
Intake Air Temperature Sensor or
Intake Air Temperature Sensor circuit
defective Correct or replace
Throttle Position Sensor or Throttle
Position Sensor circuit defective Correct or replace

ENGINE MECHANICAL (6VE1 3.5L) 6A-9
Symptom Possible Cause Action
Hesitation at high speeds Engine Control Module defective Replace
Throttle Position Sensor cable broken
or poor connections Correct or replace
Throttle Position Sensor defective Replace
Engine Coolant Temperature Sensor
circuit open or shorted Correct or replace
Engine Coolant Temperature Sensor
defective Replace
Mass Airflow Sensor circuit open or
poor connections Correct or replace
Mass Airflow Sensor defective Replace
IAT Sensor circuit open or poor
connections Correct or replace
IAT Sensor defective Replace
Throttle valve not fully opened Check and correct or replace
Air Cleaner Filter clogged Replace filter element
Power supply voltage too low Check and correct or replace

6A-10 ENGINE MECHANICAL (6VE1 3.5L)
Engine Lacks Power
Symptom Possible Cause Action
Trouble in fuel system Fuel Pressure Control Valve not
working normally Replace
Fuel injector clogged Clean or replace
Fuel pipe clogged Clean
Fuel filter clogged or fouled Replace
Fuel pump drive circuit not working
normally Correct or replace
Fuel tank not sufficiently breathing
due to clogged Evaporative Emission
Control System circuit Clean or replace
Water in fuel system Clean
Inferior quality fuel in fuel system Use fuel of specified octane rating
Engine Control Module supplied poor
voltage Correct circuit
Throttle Position Sensor cable broken
or poor connections Correct or replace
Throttle Position Sensor defective Replace
Mass Airflow Sensor not working
normally Replace
Manifold Absolute Pressure Sensor
not working normally Replace
Intake Air Temperature Sensor not
working normally Replace
Engine Coolant Temperature Sensor
circuit open or shorted Correct or replace
Engine Coolant Temperature Sensor
defective Replace
Engine Control Module defective Replace
Trouble in intake or exhaust system Air Cleaner Filter clogged Replace filter element
Air duct kinked or flattened Correct or replace
Exhaust system clogged Correct or replace
Ignition failure ———— Refer to Hard Start Troubleshooting
Guide
Heat range of spark plug inadequateInstall spark plugs of adequate heat
range
Ignition coil defective Replace

ENGINE MECHANICAL (6VE1 3.5L) 6A-11
Symptom Possible Cause Action
Engine overheating Level of Engine Coolant too low Replenish
Fan clutch defective Replace
Thermostat defective Replace
Engine Coolant pump defective Correct or replace
Radiator clogged Clean or replace
Radiator filler cap defective Replace
Level of oil in engine crankcase too
low or wrong engine oil Change or replenish
Resistance in exhaust system
increased Clean exhaust system or replace
defective parts
Throttle Position Sensor adjustment
incorrect Replace with Throttle Valve ASM
Throttle Position Sensor circuit open
or shorted Correct or replace
Cylinder head gasket damaged Replace
Engine overcooling Thermostat defective Replace (Use a thermostat set to
open at 82
C (180
F))
Engine lacks compression ———— Refer to Hard Start
Others Tire inflation pressure abnormal Adjust to recommended pressures
Brake drag Adjust
Clutch slipping Adjust or replace
Level of oil in engine crankcase too
high Correct level of engine oil
EGR valve defective Replace

ENGINE MECHANICAL (6VE1 3.5L) 6A-15
Abnormal Combustion
Symptom Possible Cause Action
Trouble in fuel system Fuel pressure control valve defectiveReplace
Fuel filter clogged Replace
Fuel pump clogged Clean or replace
Fuel tank or fuel pipe clogged Clean or replace
Fuel injector clogged Clean or replace
Fuel pump relay defective Replace
Power supply cable for fuel pump
broken or poor connections Reconnect, correct or replace
Mass Airflow (MAF) Sensor circuit
open or defective Correct or replace
MAF Sensor defective Replace
Engine Coolant Temperature (ECT)
Sensor circuit open or shorted Correct or replace
ECT Sensor defective Replace
Throttle Position Sensor adjustment
incorrect Readjust
Throttle Position Sensor defective Replace
Throttle Position Sensor connector
poor connections Reconnect
Vehicle Speed Sensor cable poor
connections or defective Correct or replace
Vehicle Speed Sensor loosely fixed Fix tightly
Vehicle Speed Sensor in wrong
contact or defective Replace
Engine Control Module cable poor
connections or defective Correct or replace

6A-20 ENGINE MECHANICAL (6VE1 3.5L)
Malfunction Indicator Lamp
The instrument panel “CHECK ENGINE" Malfunction
Indicator Lamp (MIL) illuminates by self diagnostic
system when the system checks the starting of engine,
or senses malfunctions. ”CHECK ENGINE" MIL does
not illuminate at the starting of engine

Symptom Possible Cause Action
“CHECK ENGINE" MIL does not
illuminate at the starting of engine Bulb defective Replace
MIL circuit open Correct or replace
Command signal circuit to operate
self diagnostic system shorted Correct or replace
Engine Control Module (ECM) cable
loosely connected, disconnected or
defective Correct or replace
ECM defective Replace
“CHECK ENGINE" MIL illuminates,
and stays on Deterioration of heated oxygen
sensor internal element Replace
Heated oxygen sensor connector
terminal improper contact Reconnect properly
Heated oxygen sensor lead wire
shorted Correct
Heated oxygen sensor circuit open Correct or replace
Deterioration of engine coolant
temperature sensor internal element Replace
Engine coolant temperature sensor
connector terminal improper contact Reconnect properly
Engine coolant temperature sensor
lead wire shorted Correct
Engine coolant temperature sensor
circuit open Correct or replace
Throttle position sensor open or
shorted circuits Correct or replace
Deterioration of crankshaft position
sensor Replace
Crankshaft position sensor circuit
open or shorted Correct or replace
Vehicle speed sensor circuit open Correct or replace
Intake air temperature sensor circuit
open or shorted Correct or replace
Fuel injector circuit open or shorted Correct or replace
ECM driver transistor defective Replace ECM
Malfunctioning of ECM RAM
(Random Access Memory) or ROM
(Read Only Memory) Replace ECM

ENGINE MECHANICAL (6VE1 3.5L) 6A-37
Cylinder Head
Removal
1. Remove engine hood.
2. Disconnect battery ground cable.
3. Drain radiator coolant.
4. Drain engine oil.
5. Remove crankshaft pulley.

Refer to removal procedure for Crankshaf
t
Pulley in this manual.
6. Remove timing belt.

Refer to removal procedure for Timing Belt in
this manual.
7. Remove cylinder head cover LH.

Refer to removal procedure for Cylinder Head
Cover LH in this manual.
8. Remove cylinder head cover RH.

Refer to removal procedure for Cylinder Head
Cover RH in this manual.
9. Remove common chamber.

Refer to removal procedure for Common
Chamber in this manual.
10. Remove cylinder head assembly.
1. Loosen eights bolts for tight cylinder head.
2. Remove cylinder head assembly.



014RW028
Legend
(1) Cylinder Head
(2) Cylinder Head Bolt
(3) Camshaft


Installation
1. Install cylinder head assembly to cylinder block.
1. Put cylinder head gasket on the cylinder block.
NOTE: There is discrimination mark “R" for righ
t
bank and “L" for left bank on the cylinder head
gasket as shown in the illustration.
Do not reuse cylinder head gasket.


011RW005
2. Align dowel pin hole to dowel pin on the
cylinder block.
3. Tighten two bolts temporarily by hand to
prevent the cylinder head assembly from
moving.
4. Using 9851142090 cylinder head bol
t
wrench, tighten bolts in numerical order as
shown in the illustration to the specified torque.

ENGINE MECHANICAL (6VE1 3.5L) 6A-39
Valve Stem Oil Controller, Valve Spring and Valve Guide
Removal
1. Disconnect battery ground cable.

Drain engine oil.
2. Drain engine coolant.
3. Remove cylinder head assembly.

Refer to removal procedure for Cylinder Head
in this manual.
4. Remove camshaft.

Refer to removal procedure for Camshaft in this
manual.
5. Remove tappets with shim.
NOTE: Do not damage shim surface.
6. Remove valve springs using 5884024460
valve spring compressor and 5884025470
valve spring compressor adapter then remove
upper valve spring seat and lower seat.



014RW042
7. Remove oil controller using 5884006230 oil
controller remover, remove each valve stem oil
controller.
8. Remove valve guide using 5884025490 valve
guide replacer.

Installation
1. Install valve guide using 5884024420 valve
guide installer.
2. Install oil controller using 5884006240 oil
controller installer.
3. Install lower valve spring seat, valve spring and
upper valve spring seat then put split collars on the
upper spring seat, using 5884024420 valve
spring compressor and 5884006240 valve
spring compressor adapter to install the spli
t
collars.



014RW042
4. Install tappet with shim.
5. Install camshaft assembly.

Refer to installation procedure for Camshaft in
this manual.
6. Install cylinder head assembly.

Refer to installation procedure for Cylinde
r
Head in this manual.
7. Fill engine oil until full level.
8. Fill engine coolant.

ENGINE MECHANICAL (6VE1 3.5L) 6A-49
Engine Assembly
Removal

P1010068
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 accelerator cable and automatic cruise
control cable from throttle valve on common
chamber.
7. Remove the ECM.

Disconnect the two connectors from the ECM.

. Remove fixing bolts on the common chamber.

Remove fixing bolts for ground cable.
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 (lef
t
front side of engine compartment), disconnect shift
on the fly harness connector from front side o
f
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 lef
t
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 O2 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 hose from right side o
f
transmission.
CAUTION: Plug fuel pipe on engine side and fuel
hose 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.
Installation
CAUTION: When assembling the engine and
transmission, confirm that dowels have been
mounted in the specified positions at the engine
side. Also take care that dowel positions are
different between the manual transmission and the
automatic transmission. Otherweise, the
transmission may be damaged.