overheating ISUZU TF SERIES 2004 User Guide

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

6F-2 ENGINE EXHAUST (6VE1 3.5L)
General Description



RTW46FLF000101
Legend (3) Three Way Catalytic Converter
(1) Front Exhaust Pipe LH (4) Center Exhaust Pipe
(2) Front Exhaust Pipe RH (5) Exhaust Silencer & Tail Pipe


When inspecting or replacing exhaust system
components, make sure there is adequate clearance
from all points on the underbody to prevent overheating
the floor pan and possible damage to the passenge
r
compartment insulation and trim materials.
Check complete exhaust system and nearby body
areas and rear compartment lid for broken, damaged,
missing or mispositioned parts, open seams, holes,
loose connections or other deterioration which could
permit exhaust fumes to seep into the rea
r
compartment or passenger compartment. Dust or water
in the rear compartment may be an indication of a
problem in one of these areas. Any faulty areas should
be corrected immediately.

Hangers
Various types of hangers are used to support exhaust
system(s). These include conventional rubber straps,
rubber rings, and rubber blocks.
The installation of exhaust system supports is very
important, as improperly installed supports can cause
annoying vibrations which can be difficult to diagnose.
Three Way Catalytic Converter
The three way catalytic converter is an emission control
device added to the exhaust system to reduce
pollutants from the exhaust gas stream.

6-8 ENGINE DIAGNOSIS (C24SE)
Condition Possible cause Correction
Engine overheating Level of Engine Coolant too low Replenish
Thermo switch or fan motor
defective Replace
Thermostat defective Replace
Engine Coolant pump defective Correct or replace
Radiator clogged Clean or replace
Radiator filter cap defective Replace
Level of oil in engine crankcase
too low or wrong oil in engine Change or replenish
Resistance in exhaust system
increased Clean exhaust system or replace
defective parts
Throttle Position Sensor
adjustment incorrect Adjust Wide Open Throttle switch
setting
Throttle Position Sensor circuit
open or shorted Correct or replace
Cylinder head gasket damaged Replace
Cooling Fan clutch defective Replace
Fan belt slipping Adjust tension of V-belt or replace
V-belt
Engine overcooling Thermostat defective Replace (Use a thermostat set to
open at 92
C (197.6
F))
Engine lacks compression - Refer to Hard Start
Others Tire inflation pressure abnormal Adjust to recommend pressures
Brake drag Adjust
Clutch slipping Adjust or replace
Level of oil in engine crankcase
too high Correct level of engine oil

Engine Noisy
Abnormal engine noise often consists of various
noises originating in rotating parts, sliding parts and
other moving parts of the engine. It is, therefore,
advisable to locate the source of noise systematically.

Condition Possible cause Correction
Noise from crank journals or from
crank bearings
(Faulty crank journals and crank
bearings usually make dull noise
that becomes more evident when
accelerating) Oil clearance increased due to
worn crank journals or crank
bearings Replace crank bearings and
crankshaft or regrind crankshaft
and install the over size bearing
Crankshaft out of round Replace crank bearings and
crankshaft or regrind crankshaft
and install the over size bearing
Crank bearing seized Replace crank bearings and
crankshaft or regrind crankshaft
and install the over size bearing

6-10 ENGINE DIAGNOSIS (C24SE)
Troubleshooting Procedure

Condition Possible cause Correction
Piston pin noise
(Piston makes noise each time it
goes up and down) Piston pin or piston pin hole worn Replace piston, piston pin and
connecting rod assy

Troubleshooting Procedure
The slapping sound stops when spark plug on bad
cylinder is shorted out.

Condition Possible cause Correction
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 wheels defective Replace
Timing belt comes in contact with
timing cover Replace timing belt and timing
cover
Valve noise Valve and valve guide seized Replace valve and valve guide
Valve spring broken Replace
Valve seat off-positioned Correct
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
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 or incorrect gear
selection
Engine overheating Refer to "Engine Lacks Power"
Others Water pump defective Replace
V-belt slipping Adjust tension of V-belt or replace
V-belt

ENGINE COOLING 6B-5
Diagnosis
Engine Cooling Trouble
Condition Possible cause Correction
Engine overheating Low Engine Coolant level Replenish
Thermo mater 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
Loosen V-belt tension Adjust belt tension or replace.
Collapsed hoses Replace
Faulty Fan clutch Replace
Engine overcooling Faulty thermostat Replace
Engine slow to warm-up Faulty thermostat Replace
Thermo unit faulty Replace

6B-12 ENGINE COOLING


Inspection
Radiator Cap
Measure the valve opening pressure of the pressurizing valve
with a radiator filler cap tester.
Replace the cap if the valve opening pressure is outside the
standard range.
Valve opening pressure kPa (psi) 88.3 – 103.0
(13.5 – 15.7)
Cap tester: 5-8840-0277-0
Adapter: 5-8840-2603-0
Check the condition of the vacuum valve in the center of the
valve seat side of the cap. If considerable rust or dirt is found,
or if the valve seat cannot be moved by hand, clean or replace
the cap.
Valve opening vacuum kPa (psi) 1.9 - 4.9
(0.28 - 0.71)



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 sign 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

ENGINE DRIVEABILITY AND EMISSIONS 6E–65
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. Nex t, confine the problem into a smaller
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 power 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 nex t page for
problem simulation procedures. Refer to service manual
sections 6E and 8A for information about 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 II and Tech II upload function
Circuit testing tools (including connector kits/
harnesses and jumper wires)
Ex perience
Intermittent problem solving simulation methods
Customer complaint check sheet
Symptom Simulation Tests
1. Vibration
This method is useful when the customer complaint
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 joint
and body for damage. Also, tapping lightly along a
suspected circuit may be helpful.For parts and sensors, apply slight vibration to the part
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 or
similar tool while monitoring the system for a
malfunction.
CA UTION: 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 under
conditions of high humidity. In this case, apply water in a
light spray on the vehicle to duplicate the problem.
CA UTION: 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.
5e. Vehicle Operates as Designed
This condition refers to instances where a system
operating as designed is perceived to be unsatisfactory
or undesirable. In general, this is due to:
A lack of understanding by the customer
A conflict between customer ex pectations and
vehicle design intent
A system performance that is unacceptable to the
customer
What you should do
You can verify that a system is operating as designed
by:
Reviewing service manual functional/diagnostic
checks
Ex amining bulletins and other service information for
supplementary information
Compare system operation to an identical vehicle
If the condition is due to a customer misunderstanding
or a conflict between customer ex pectation and system
operation, you should ex plain the system operation to
the customer.
If the complaint is due to a case of unsatisfactory
system performance, you should contact Technical
Assistance for the latest information.
What resources you should use
Whenever possible, you should use the following
resources to facilitate the diagnostic process:

6E–254 ENGINE DRIVEABILITY AND EMISSIONS
DETONATION/SPARK KNOCK SYMPTOM
DEFINITIONS: A mild to severe ping, usually worse under acceleration. The engine makes a sharp metallic knocking
sound that changes with throttle opening. Prolonged detonation may lead to complete engine tailure.
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?—Go to Step 2Go to 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 visual/physical check performed?
—Go to Step 4Go 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 5Verify repair
5 1. Check for obvious overheating problems:
Low engine coolant
Restricted air flow to radiator
Incorrect coolant solution
2. If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 6
6 Check the fuel pressure. Refer to 6E-108 page “Fuel
System Diagnosis” .
Was a problem found?—Verify repair Go to Step 7
7 1. Using a Tech 2, display the MAP sensor value in
comparison with atmosphere temperature.
2. Check for a faulty, plugged, or incorrectly installed
MAP sensor.
Was the problem found?—Verify repair Go to Step 8
8 1. Using a Tech 2, display the ECT sensor and IAT
sensor value and warm up condition compared
with the typical data.
2. Check the specified value or wire.
Was the problem found?—Verify repair Go to Step 9
9 Observe the throttle position display on the Tech 2
while slowly increasing throttle pedal.
Does the throttle position increase steady with
increasing smoothly?
—Go to Step 10Refer to
Diagnostic
Trouble Code
P0123 for
further
diagnosis
10 Check the knock sensor wire, shield wire, or
installation condition.
Was a problem found?—Verify repair Go to Step 11
11 Check items that can cause the engine to run lean.
Refer to DTC P1171 “Fuel Supply System Lean
During Power Enrichment”.
Was a problem found?—Verify repair Go to Step 12