2004 ISUZU TF SERIES heating

6A-14 ENGINE MECHANICAL (6VE1 3.5L)
Troubleshooting Procedure
The slapping sound stops when spark plug on bad
cylinder is shorted out.

Symptom Possible Cause Action
Timing belt noise Timing belt tension is incorrect Replace pusher or adjust the tension
pulley or replace timing belt
Tensioner bearing defective Replace
Timing belt defective Replace
Timing pulley defective Replace
Timing belt comes in contact with
timing cover Replace timing belt and timing cover
Valve noise Valve clearance incorrect Replace adjusting shim
Valve and valve guide seized Replace valve and valve guide
Valve spring broken or weakened Replace
Valve seat off–positioned Correct
Camshaft worn out Replace
Crankshaft noise Crankshaft end play excessive (noise
occurs when clutch is engaged) Replace thrust bearing
Engine knocking Preignition due to use of spark plugs
of inadequate heat range Install Spark Plugs of adequate heat
range
Carbon deposits in combustion
chambers Clean
Fuel too low in octane rating Replace fuel
Wide Open Throttle enrichment
system failure Refer to Section 6E
Selection of transmission gear
incorrect Caution operator of incorrect gear
selection
Engine overheating Refer to “Engine Lacks Power"
Others Water pump defective Replace
Drive belt slipping Replace auto tentioner or drive belt

6A-80 ENGINE MECHANICAL (6VE1 3.5L)
5. Remove oil strainer and O-ring (5).
6. Remove oil gallery (6).
7. Remove connecting rod cap with connecting rod
lower bearing (12).
8. Remove piston and connecting rod assembly (7).
NOTE: Before removing piston and connecting rod
assembly, measure thrust clearance.






015RS031
 Remove any ridge or carbon build up from the
top end of the cylinder.
9. Remove the piston rings (8) with a piston ring
expander. Arrange the removed piston rings in the
cylinder number order.

015RS022
10. Remove the piston pin (9) using 5
8840
0551
0
piston pin service set and piston support with a
press.
NOTE: Keep the parts removed from each cylinde
r
separate. All parts must be reinstalled in their original
positions. Heating the connecting rod will permit easy
removal of the piston pin.


015RX001
Legend
(1) Press Ram
(2) Piston
(3) Connecting Rod
(4) Piston Pin

11. Piston (10)
12. Connecting rod (11)
Inspection and Repair
Pistons (10)
Carefully clean away all the carbon adhering to the
piston head and the piston ring grooves.
NOTE: Never use a wire brush to clean the pistons.
Damage will result. Visually check each piston fo
r
cracking, scoring, and other signs of excessive wear. If
any of the above conditions are found, the piston must
be replaced.
Piston Diameter
1. Measure the piston outside diameter with
micrometer at the piston grading position and a
right angle to the piston pin.
Piston grading position (from piston head)
Piston grading position : 43.0 mm (1.6929 in)

ENGINE COOLING (6VE1 3.5L) 6B-5
Diagnosis
Engine Cooling Trouble
Symptom Possible Cause Action
Engine overheating Low Engine Coolant level Replenish
Thermo meter unit faulty Replace
Faulty thermostat Replace
Faulty Engine Coolant temperature
sensor Repair or replace
Clogged radiator Clean or replace
Faulty radiator cap Replace
Low engine oil level or use of
improper engine oil Replenish or change oil
Clogged exhaust system Clean exhaust system or replace
faulty parts
Faulty Throttle Position sensor Replace throttle valve assembly
Open or shorted Throttle Position
sensor circuit Repair or replace
Damaged cylinder head gasket Replace
Engine overcooling Faulty thermostat Replace
Engine slow to warm–up Faulty thermostat Replace
Thermo unit faulty Replace

6B-12 ENGINE COOLING (6VE1 3.5L)
Valve opening vacuum kPa (psi) 1.96




4.91 (0.28





0.71)


110RS006
Radiator Core
1. A bent fin may result in reduced ventilation and
overheating may occur. All bent fins must be
straightened. Pay close attention to the base of the
fin when it is being straightened.
2. Remove all dust, bugs and other foreign material.
Flushing the Radiator
Thoroughly wash the inside of the radiator and the
engine coolant passages with cold water and mild
detergent. Remove all signs of scale and rust.
Cooling System Leakage Check
Use a radiator cap tester to force air into the radiator
through the filler neck at the specified pressure of 196
kPa (28.5 psi) with a cap tester:
 Leakage from the radiator
 Leakage from the coolant pump
 Leakage from the water hoses
 Check the rubber hoses for swelling.

Cap tester: 5–8840–0277–0
Adapter: 5–8840–2603–0


110RS005
Installation
1. Install radiator assembly (9) with hose, taking care
not to damage the radiator core with a fan blade.
2. Support the radiator upper tank with the bracket (5)
and secure the radiator.
3. Connect reserve tank hose (6).
4. Install lower fan guide (3).
5. Connect radiator inlet hose and outlet hose (1) to
the engine.

ENGINE COOLING (6VE1 3.5L) 6B-13
6. Connect oil cooler hose to automatic transmission.




RTW36BSH000101
7. Connect battery ground cable.
8. Pour engine coolant up to filler neck of radiator, and
up to MAX mark of reserve tank.




RTW36BSH000101
Important operation (in case of 100% engine
coolant change) procedure for filling with engine
coolant.

Engine coolant change
1. To change engine coolant, make sure that the
engine is cool.
WARNING: When the coolant is heated to a high
temperature, be sure not to loosen or remove the
radiator cap. Otherwise you might get scalded by
hot vapor or boiling water. To open the radiato
r
cap, put a piece of thick cloth on the cap and
loosen the cap slowly to reduce the pressure when
the coolant has become cooler.
2. Open radiator cap and drain the cooling system by
loosening the drain valve on the radiator and on the
cylinder body.
NOTE: For best result it is suggested that the engine
cooling system be flushed at least once a year. It is
advisable to flash the interior of the cooling system
including the radiator before using anti-freeze
(ethylene-glycol based).
Replace damaged rubber hoses as the engine
anti-freeze coolant is liable to leak out even mino
r
cracks.
Isuzu recommends to use Isuzu genuine anti-freeze
(ethylen-glycol based) or equivalent, for the cooling
system and not add any inhibitors or additives.
CAUTION: A failure to correctly fill the engine
cooling system in changing or topping up coolant
may sometimes cause the coolant to overflow from
the filler neck even before the engine and radiato
r
are completely full.
If the engine runs under this condition, shortage o
f
coolant may possibly result in engine overheating.
To avoid such trouble, the following precautions
should be taken in filling the system.
3. To refill engine coolant, pour coolant up to filler neck
using a filling hose which is smaller in outside
diameter of the filler neck. Otherwise air between
the filler neck and the filling hose will block entry,
preventing the system from completely filling up.
4. Keep a filling rate of 9 liter/min. or less. Filling ove
r
this maximum rate may force air inside the engine
and radiator.
And also, the coolant overflow will increase, making
it difficult to determine whether or not the system is
completely full.
5.
After filling the system to the full, pull out the filling
hose and check to see if air trapped in the system is
disclodged and the coolant level goes down. Should
the coolant level go down, repeat topping-up until
there is no more drop in the coolant level.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-67
What you should do
Step 1: Acquire information
A thorough and comprehensive customer check sheet
is critical to intermittent problem diagnosis. You should
require this, since it will dictate the diagnostic starting
point. The vehicle service history file is another
source for accumulating information about the
complaint.

Step 2: Analyze the intermittent problem
Analyze the customer check sheet and service history
file to determine conditions relevant to the suspect
system(s).
Using service manual information, you must identify,
trace and locate all electrical circuits related to the
malfunctioning system(s). If there is more than one
system failure, you should identify, trace and locate
areas of commonality shared by the suspect circuits.

Step 3: Simulate the symptom and isolate the
problem
Simulate the symptom and isolate the system by
reproducing all possible conditions suggested in Step 1
while monitoring suspected circuits/components
/
systems to isolate the problem symptom. Begin with the
most logical circuit/component.
Isolate the circuit by dividing the suspect system into
simpler circuits. Next, confine the problem into a smalle
r
area of the system. Begin at the most logical point (or
point of easiest access) and thoroughly check the
isolated circuit for the fault, using basic circuit tests.

Hints
You can isolate a circuit by:

Unplugging connectors or removing a fuse to
separate one part of the circuit from another

If only component fails to operate, begin testing
the component

If a number of components do not operate, begin
test at areas of commonality (such as powe
r
sources, ground circuits, switches, main
connectors or major components)

Substitute a known good part from the parts
department or the vehicle system

Try the suspect part in a known good vehicle See
Symptom Simulation Tests on the next page fo
r
problem simulation procedures. Refer to service
manual sections 6E and 8A for information abou
t
intermittent diagnosis. Follow procedures for basic
circuit testing in service manual section 8A.
What resources you should use
Whenever appropriate, you should use the following
resources to assist in the diagnostic process:

Service manual

Bulletins

Digital multimeter (with a MIN/MAX feature)

Tech 2 and Tech 2 upload function

Circuit testing tools (including connecto
r
kits/harnesses and jumper wires)

Experience

Intermittent problem solving simulation methods

Customer complaint check sheet
Symptom Simulation Tests
1. Vibration
This method is useful when the customer complain
t
analysis indicates that the problem occurs when the
vehicle/system undergoes some form of vibration.
For connectors and wire harness, slightly shake
vertically and horizontally. Inspect the connector join
t
and body for damage. Also, tapping lightly along a
suspected circuit may be helpful.
For parts and sensors, apply slight vibration to the par
t
with a light tap of the finger while monitoring the system
for a malfunction.
2. Heat
This method is important when the complaint suggests
that the problem occurs in a heated environment. Apply
moderate heat to the component with a hair drier o
r
similar tool while monitoring the system for a
malfunction.
CAUTION: Care must be take to avoid overheating
the component.
3. Water and Moisture
This method may be used when the complaint suggests
that the malfunction occurs on a rainy day or unde
r
conditions of high humidity. In this case, apply water in
a light spray on the vehicle to duplicate the problem.
CAUTION: Care must be take to avoid directly
exposing electrical connections to water.
4. Electrical loads
This method involves turning systems ON (such as the
blower, lights or rear window defogger) to create a load
on the vehicle electrical system at the same time you
are monitoring the suspect circuit/component.

6E-70 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Fuel Quality
Fuel quality is not a new issue for the automotive
industry, but its potential for turning on the MIL (“Check
Engine" lamp) with OBD systems is new.
Fuel additives such as “dry gas" and “octane
enhancers" may affect the performance of the fuel. The
Reed Vapor Pressure of the fuel can also create
problems in the fuel system, especially during the spring
and fall months when severe ambient temperature
swings occur. A high Reed Vapor Pressure could sho
w
up as a Fuel Trim DTC due to excessive canister
loading. High vapor pressures generated in the fuel
tank can also affect the Evaporative Emission
diagnostic as well.
Using fuel with the wrong octane rating for your vehicle
may cause driveability problems. Many of the majo
r
fuel companies advertise that using “premium" gasoline
will improve the performance of your vehicle. Mos
t
premium fuels use alcohol to increase the octane rating
of the fuel. Although alcohol-enhanced fuels may raise
the octane rating, the fuel's ability to turn into vapor in
cold temperatures deteriorates. This may affect the
starting ability and cold driveability of the engine.
Low fuel levels can lead to fuel starvation, lean engine
operation, and eventually engine misfire.
Non-OEM Parts
All of the OBD diagnostics have been calibrated to run
with OEM parts.
Aftermarket electronics, such as cellular phones,
stereos, and anti-theft devices, may radiate EMI into the
control system if they are improperly installed. This may
cause a false sensor reading and turn on the MIL
(“Check Engine" lamp).
Environment
Temporary environmental conditions, such as localized
flooding, will have an effect on the vehicle ignition
system. If the ignition system is rain-soaked, it can
temporarily cause engine misfire and turn on the MIL
(“Check Engine" lamp).
Vehicle Marshaling
The transportation of new vehicles from the assembly
plant to the dealership can involve as many as 60 key
cycles within 5Km miles of driving. This type o
f
operation contributes to the fuel fouling of the spark
plugs and will turn on the MIL (“Check Engine" lamp).

Poor Vehicle Maintenance
The sensitivity of OBD diagnostics will cause the MIL
(“Check Engine" lamp) to turn on if the vehicle is no
t
maintained properly. Restricted air filters, fuel filters,
and crankcase deposits due to lack of oil changes o
r
improper oil viscosity can trigger actual vehicle faults
that were not previously monitored prior to OBD. Poo
r
vehicle maintenance can not be classified as a
“non-vehicle fault", but with the sensitivity of OBD
diagnostics, vehicle maintenance schedules must be
more closely followed.
Severe Vibration
The Misfire diagnostic measures small changes in the
rotational speed of the crankshaft. Severe driveline
vibrations in the vehicle, such as caused by an
excessive amount of mud on the wheels, can have the
same effect on crankshaft speed as misfire.
Related System Faults
Many of the OBD system diagnostics will not run if the
ECM detects a fault on a related system or component.
One example would be that if the ECM detected a
Misfire fault, the diagnostics on the catalytic converte
r
would be suspended until Misfire fault was repaired. If
the Misfire fault was severe enough, the catalytic
converter could be damaged due to overheating and
would never set a Catalyst DTC until the Misfire faul
t
was repaired and the Catalyst diagnostic was allowed to
run to completion. If this happens, the customer may
have to make two trips to the dealership in order to
repair the vehicle.
Maintenance Schedule
Refer to the Maintenance Schedule.
Visual/Physical Engine Compartment
Inspection
Perform a careful visual and physical engine
compartment inspection when performing any
diagnostic procedure or diagnosing the cause of an
emission test failure. This can often lead to repairing a
problem without further steps. Use the following
guidelines when performing a visual/physical inspection:

Inspect all vacuum hoses for punches, cuts,
disconnects, and correct routing.

Inspect hoses that are difficult to see behind othe
r
components.

Inspect all wires in the engine compartment fo
r
proper connections, burned or chafed spots, pinched
wires, contact with sharp edges or contact with ho
t
exhaust manifolds or pipes.

6E-356 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DETONATION/SPARK KNOCK SYMPTOM
DEFINITIONS: A mild to sever ping, usually worse
under acceleration. The engine makes a shape metallic
knocking sound that changes with throttle opening.
Prolonged detonation may lead to complete engine
failure.



Step Action Value (s) Yes No
1
Was the "On-Board Diagnostic (OBD) System Check"
performed?
- Go to Step 2 Go to On Board
Diagnostic (OBD)
System Check
2
1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
- Verify repair Go to Step 3
3
Was a visually/physical check performed?
- Go to Step 4 Go to Visual /
physical Check.
4
1. If Tech 2 readings are normal (refer to Typical Scan
Data Values) and there are no engine mechanical
faults, fill the fuel tank with a known quality
gasoline.
2. Re-evaluate the vehicle performance.
Is detonation present?
- Go to Step 5
Verify repair
5
Check for obvious overheating problems:

Low engine coolant.

Restricted air flow to radiator.

Incorrect coolant solution.
If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 6
6
1. Using a Tech 2, display the ECT sensor and IAT
sensor value.
2. Check the specified value or wire.
Was the problem found?
- Verify repair Go to Step 7