2004 ISUZU TF SERIES engine overheat

TROUBLESHOOTING 6 – 1


SECTION 6
TROUBLESHOOTING


TABLE OF CONTENTS
PAGE PAGE
BASIC INSPECTION PROCEDURE ... 6– 2

1. HARD STARTING ........................... 6– 3

1-1.Starter Motor Inoperative ......... 6– 3

1-2. Starter Motor Operates But
Engine Does Not Turn Over .......... 6– 3

1-3. Engine Turns Over But Does
Not Start Engine ............................. 6– 4

2. UNSTABLE IDLING ........................ 6– 5

3. INSUFFICIENT POWER ................. 6– 6

4. EXCESSIVE FUEL
CONSUMPTION ................................. 6– 7

5. EXCESSIVE OIL CONSUMPTION.. 6– 8

6. OVERHEATING............................... 6– 9

7. WHITE EXHAUST SMOKE ............. 6– 9

8. DARK EXHAUST SMOKE .............. 6– 10

9. OIL PRESSURE DOES NOT RISE . 6– 11

10. ABNORMAL ENGINE NOISE ....... 6– 12

10-1. Engine Knocking.................... 6– 12

10-2. Gas Leakage Noise ................ 6– 12

10-3. Continuous Noise .................. 6– 13

10-4. Slapping Noise ....................... 6– 13

10-5. Excessive Turbocharger
Noise ............................................... 6– 14
11. ROTATING PART WEAR OF
TURBOCHARGER ............................. 6– 14

12. OIL LEAKAGE FROM
TURBOCHRGER ............................... 6– 15

13. INSUFFICIENT ACCELERATION
AND/OR LACK OF POWER DUE
TO TURBOCHARGER ....................... 6– 15

14. BATTERY CHARGING AND
NOISE PROBLEM.............................. 6– 16

14-1. Battery No Charging .............. 6– 16

14-2. Battery Overcharging ............ 6– 16

14-3. Battery Under Charging......... 6– 17

14-4. Battery Unstable Charging
Current ............................................ 6– 17

14-5. Charging System Noise ......... 6– 18

15. STARTER MOTOR PROBLEM..... 6– 19

15-1. Starter Motor Pinion Engages
to Ring Gear But Engine Does
Not Turn Over ................................. 6– 19

15-2. Incorrect Pinion And Ring
Gear Engagement .......................... 6– 19

15-3. Starter Motor Continues To
Run After The Starter Switch Is
Turned Off ....................................... 6– 20

15-4. Excessive Commutator
Sparking .......................................... 6– 20

TROUBLESHOOTING 6 – 9
6. Overheating
Step Action Value(s) Yes No
1 Was the engine coolant level OK? —
Go to Step 2 Replenish the
coolant
2 Was the water leakage or the radiator restriction
found? (Include radiator cap) — Repair or
replace the
leakage part. Go to Step 3
3 Was the fan belt slippage found? — Tension or
replace the fan
belt. Go to Step 4
4 Was the fan clutch working completely? —
Go to Step 5 Replace the
fan clutch
assembly.
5 Was the oil leakage found from fan clutch? — Replace the
fan clutch
assembly Go to Step 6
6 Was the thermostat working normally? —
Go to Step 7 Replace the
thermostat.
7 Was the water pump working OK? —
Go to Step 8 Replace the
water pump
assembly.
8 Was the restriction by the foreign materials in the
cooling system found? For example, clog the water
hose between the cylinder body and radiator etc.. — Clean or
replace the
clog part. Go to Step 9
9 Was the water leakage found from the sealing cap
on the cylinder body? — Replace the
sealing cap or
replace the
cylinder body. Go to Step 10
10 Are any DTC stored? — Go to indicated
DTC. Solved

7. White Exhaust Smoke
Step Action Value(s) Yes No
1 Was the compression pressure OK? 3.0 MPa
(31.0 kg/cm2,
441 psi) at
200 rpm
Go to Step 2 Readjust the
valve clearance
or replace the
cylinder head
gasket or
cylinder liner or
piston or piston
ring or valve
and relation
parts.
2 Was the PCV (Positive Crankcase Ventilation) valve
working completely? —
Go to Step 3 Repair or
replace the
PCV valve.
3 Was the turbocharger working completely? —
Go to Step 4 Replace the
turbocharger.
4 Are any DTC stored? — Go to indicated
DTC Solved

ENGINE COOLING 6B – 7
DIAGNOSIS
Engine Cooling Trouble
Symptom Possible Cause Action
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
Engine overheating
Damaged cylinder head gasket Replace
Engine overcooling Faulty thermostat Replace
Faulty thermostat Replace Engine slow to warm–up
Thermo unit faulty Replace

ENGINE COOLING 6B – 17
Inspection and Repair
Make the necessary adjustments, repairs, and part
replacements if excessive wear or damage is discovered
during 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) 93.3





122.7 (13.5





17.8)
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.





110RS006

Valve opening vacuum kPa (psi) 1.96




4.91 (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 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

6E–80 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
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:

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–303
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.
Was the DTC P1173 (Symptom Code 3) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Check the engine overheat condition.
Was the problem found?
—Repair the
cause of
overheat and
verify repair Go to Step 5
5 1. Using the Tech 2, ignition “On” and engine “On”.
2. Monitor the “Coolant Temperature” in the data
display.
Does the Tech 2 indicate correct “Coolant
Temperature” depending on warm up time?—Go to Step 9Go to Step 6
6 Using the DVM and check the ECT sensor.
1. Ignition “Off”, engine “Off”.
2. Disconnect ECT sensor connector.
3. Measure the resistance of ECT sensor.
Does the tester indicate standard resistance as shown
in the following table?
Standard
resistance Go to Step 9Go to Step 7
7 Substitute a known good ECT sensor assembly and
recheck.
Was the problem solved?—Go to Step 8Go to Step 9
8 Replace the ECT sensor.
Is the action complete?—Verify repair—
9 Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?—Verify repair Go to Step 10 Step Action Value(s) Yes No
Temperature (°C) Re sista nce (
) (Appro xima te ly )
-20 16100
0 5760
20 2370
40 1080
60 537
80 290
100 161
120 95
1 2
ECT Sensor
1 2

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

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