spark plugs replace ISUZU TROOPER 1998 Service Repair Manual

0BÐ2 MAINTENANCE AND LUBRICATION
MAINTENANCE SCHEDULE
GASOLINE ENGINE MODELI: Inspect and correct or replace as necessary A: Adjust
R: Replace or change T: Tighten to specified torque L: Lubricate
SERVICE INTERVAL: x 1,000 km
(Use odometer reading x 1,000 miles
or months whichever comes first) or months5
3
610
6
1215
9
1820
12
2425
15
3030
18
3635
21
4240
24
4845
27
5450
30
6055
33
6660
36
7265
39
7870
42
8475
45
9080
48
9685
51
10290
54
10895
57
114100
60
120
GASOLINE ENGINE
* Engine oil
* Engine oil filter
Oil leakage and contamination
* Timing belt
Spark plugs (For leaded fuel use)
Spark plugs (For unleaded fuel use)
Exhaust system
Radiator coolant concentration
Cooling system for water leakage
All hoses and pipes in engine compartment
for clog or damage
Fuel filter
Fuel leakage
Fuel tank
* Air cleaner element
Pre air cleaner
Engine drive belt
Valve clearance
O
2 Sensor (For leaded fuel use)
O
2 Sensor (For unleaded fuel use)-
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R
(Replace every 165,000 km or 100,000 miles)
(Replace every 165,000 km or 100,000 miles)
(Check and adjust if necessary every 100,000 km or 60,000 miles)
(Replace every 150,000 km or 90,000 miles)
CLUTCH
Clutch fluid
Clutch pedal travel and free play
TRANSMISSION OR TRANSMISSION WITH
TRANSFER CASE
* Manual transmission with transfer case oil
* Automatic transmission fluid leakage
*
(1)Automatic transmission fluid
* Transfer case oil
PROPELLER SHAFT
Loose connections
*
Universal joints and splines for wear
Universal joints and sliding sleeve (front and rear)
FRONT AND REAR AXLE
* Differential gear oil (Front and rear)
Shift on the fly system gear oil
Front axle shaft rubber boot for damage
Axle case for distortion or damage
Axle shafts for distortion or damage-
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ATATAT
STEERING
* Power steering fluid
Oil leakage
* Steering system for looseness or damage
Power steering hose
Steering wheel play
Steering function
Right and left turning radius
Wheel alignment
Joint ball for oil leakage or damage
Joint ball rubber boot for damage
SERVICE BRAKES
Brake fluid
Brake system for fluid leakage
Brake function
* Disc brake pads and discs wear
Brake pedal travel and free play
Pipes and hoses for loose connections or damage
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(1): Adjust or change automatic transmission fluid.
*Marks: Under severe driving conditions, additional maintenance is required.
Refer to “Maintenance schedule under severe driving conditions”.

6A±5
ENGINE MECHANICAL
4. Engine Lacks Compression
Condition
Possible causeCorrection
Engine lacks compressionSpark plug loosely fitted or spark
plug gasket defectiveTighten to specified torque or replace
gasket
Valve timing incorrectAdjust
Cylinder head gasket defectiveReplace gasket
Valve incorrectly seatedLap valve
Valve stem seizedReplace valve and valve guide
Valve spring weakened or brokenReplace
Cylinder or piston rings wornOverhaul engine
Piston ring seizedOverhaul engine.
Engine Compression Test Procedure
1. Start and run the engine until the engine reaches
normal operating temperature.
2. Turn the engine off.
3. Remove all the spark plugs.
4. Remove ignition coil fuse (15A) and disable the
ignition system.
5. Remove the fuel pump relay from the relay and fuse
box.
6. Engage the starter and check that the cranking speed
is approximately 300 rpm.7. Install cylinder compression gauge into spark plug
hole.
8. With the throttle valve opened fully, keep the starter
engaged until the compression gage needle reaches
the maximum level. Note the reading.
9. Repeat the test with each cylinder.
If the compression pressure obtained falls below the
limit, engine overhaul is necessary.
Limit; 1000 kPa (145 psi)

6A±7
ENGINE MECHANICAL
Condition CorrectionPossible cause
OthersEngine lacks compressionRefer to ªHard Startº
Valve incorrectly seatedLap valve
Air Cleaner Filter cloggedReplace filter element
Valve timing incorrectReadjust
Idle air control valve brokenReplace
Fast idle solenoid defectiveReplace
Positive Crankcase Ventilation valve
defective or cloggedReplace
Rough Engine Running
ConditionPossible causeCorrection
Engine misfires periodicallyIgnition coil layer shortedReplace
Spark plugs foulingClean or install hotter type plug
Spark plug(s) insulator nose leakingReplace
Fuel injector(s) defectiveReplace
Powertrain control module faultyReplace
Engine knocks periodicallySpark plugs running too hotInstall colder type spark plugs
Powertrain control module faultyReplace
Engine lacks powerSpark plugs fouledClean
Fuel injectors defectiveReplace
Mass Airflow Sensor or Intake
Airflow Sensor circuit defectiveCorrect or replace
Manifold Absolute Pressure (MAP)
Sensor or Manifold Absolute
Pressure Sensor circuit defectiveCorrect or replace
Engine Coolant Temperature Sensor
or Engine Coolant Temperature
Sensor circuit defectiveCorrect or replace
Powertrain Control Module faultyReplace
Intake Air Temperature Sensor or
Intake Air Temperature Sensor
circuit defectiveCorrect or replace
Throttle Position Sensor or Throttle
Position Sensor circuit defectiveCorrect or replace
Knock Sensor or Knock Sensor
circuits defectiveCorrect or replace
Knock Sensor Module or Knock
Sensor Module circuits defectiveCorrect or replace

6A±10
ENGINE MECHANICAL
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
Ignition failureÐÐÐÐRefer to Hard Start Troubleshooting
Guide
Heat range of spark plug inadequateInstall spark plugs of adequate heat
range
Ignition coil defectiveReplace

6A±13
ENGINE MECHANICAL
Condition CorrectionPossible cause
Engine knockingPreignition due to use of spark plugs
of inadequate heat rangeInstall Spark Plugs of adequate heat
range
Carbon deposits in combustion
chambersClean
Fuel too low in octane ratingReplace fuel
Wide Open Throttle enrichment
system failureRefer to Section 6E
Selection of transmission gear
incorrectCaution operator of incorrect gear
selection
Engine overheatingRefer to ªEngine Lacks Powerº
OthersWater pump defectiveReplace
Drive belt slippingReplace auto tentioner or drive belt
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

6A±53
ENGINE MECHANICAL
2. Remove camshaft bracket fixing bolt (5), camshaft
bracket (6), then camshaft exhaust (7), and intake
side (8).
3. Remove tappet with shim (11).
4. Use the 5±8840±2446±0 valve spring compressor
and 5±8840±2547±0 valve spring compressor
adapter to remove the split collar (12), valve spring
with upper seat (13) and valve (14).
014RW042
5. Remove spark plug (1).
CAUTION: Do not remove the spark plugs when the
head and plugs are hot. Clean dirt and debris from
spark plug recess areas before removal.
Clean
Cylinder head
Carefully remove all varnish, soot and carbon from the
bare metal. Do not use a motorized wire brush on any
gasket sealing surface.
Inspection and Repair
1. Cylinder head gasket and mating surfaces for leaks,
corrosion and blow±by. If the gasket has failed,
determine the cause.
± Insufficient torque on head bolts.
± Improper installation
± Loose or warped cylinder head
± Missing dowel pins
± Warped case surface
2. Cylinder head for cracks, especially between valve
seats and in the exhaust ports.3. Cylinder head deck for corrosion, sand particles in
head and porosity.
CAUTION:

Do not attempt to weld the cylinder head. Replace
it.

Do not reuse cylinder head bolts.
4. Cylinder head deck, common chamber and exhaust
manifold mating surfaces for flatness. These
surfaces may be reconditioned by milling. If the
surfaces are ªout of flatº by more than specification,
the surface should be ground to within specifications.
Replace the head if it requires machining beyond the
repairable limit.
Head surface and manifold surface
Standard: 0.05 mm (0.002 in) or less
Warpage limit: 0.2 mm (0.0079 in)
Maximum Repairable limit: 0.2 mm (0.0079 in)
Head height
Standard height : 133.2 mm (5.2441 in)
Warpage limit : 0.2 mm (0.0079 in)
Maximum Repairable limit : 133.0 mm (5.2362 in)011RW019
5. Water jacket sealing plugs seating surfaces.
Reassembly
1. Install Spark plug and tighten all the spark plugs to
specified torque.
Torque: 18 N´m (1.8 Kg´m/13 lb ft)
2. Tighten sub gear setting bolt.
1. Use 5±8840±2443±0 gear spring lever to turn sub
gear to right direction until the M5 bolt aligns with
the hole between camshaft driven gear and sub
gear.

6D2±4
IGNITION SYSTEM
Spark Plug
Removal
1. Remove spark plugs.
Inspection and Repair
The spark plug affects entire engine performance and
therefore its inspection is very important.

Check electrode and insulator for presence of cracks,
and replace if any.

Check electrode for wear, and replace if necessary.

Check gasket for damage, and replace if necessary.

Measure insulation resistance with an ohmmeter, and
replace if faulty.

Adjust spark plug gap to 1.0 mm (0.04 in) ~ 1.1 mm
(0.043 in).

Check fuel and electrical systems if spark plug is
extremely dirty.

Use spark plugs having low heat value (hot type plug)
if fuel and electrical systems are normal.

Use spark plugs having high heat value (cold type
plug) if insulator and electrode are extremely burned.
Sooty Spark Plugs
Much deposit of carbon or oil on the electrode and
insulator of spark plug reduces the engine performance.
Possible causes:

Too rich mixture

Presence of oil in combustion chamber

Incorrectly adjusted spark plug gap
Burning Electrodes
This fault is characterized by scorched or heavily oxidized
electrode or blistered insulator nose.
Possible causes:

Too lean mixture

Improper heat value
Measuring Insulation Resistance

Measure insulation resistance using a 500 volt
megaohm meter.

Replace spark plugs if measured value is out of
standard.
Insulation resistance: 50 M
or more
011RS010
Cleaning Spark Plugs

Clean spark plugs with a spark plug cleaner.

Raise the ground electrode to an angle of 45 to 60
degrees. If electrode is wet, dry it before cleaning.

After spark plug is thoroughly cleaned, check
insulator for presence of cracks.

Clean threads and metal body with a wire brush.

File the electrode tip if electrode is extremely worn.

Bend the ground electrode to adjust the spark plug
gap.
011RS011
Installation
1. Spark plugs

Tighten spark plugs to the specified torque.
Torque: 18 N´m (1.8 Kg´m/13 lb ft)

6E±82
ENGINE DRIVEABILITY AND EMISSIONS
Engine Cranks But Will Not Run

 
StepNo Ye s Value(s) Action
131. Remove any ignition coil and install a spark tester at
the spark plug end of the coil.
2. Observe the tester while the engine is cranking.
Was a crisp, blue spark observed? Only one or two
sparks followed by no result is considered the same as
ªNo Spark.º
ÐGo to Step 15Go to Step 14
14Replace the ignition coil, and return to Step 13 to test
the remaining coils.
Is the action complete?
ÐVerify repairÐ
15Repeat Step 13 for each coil. Remove only one coil at a
time, and reinstall each coil on its spark plug after
testing, but do not refasten coils with screws at this
time.
After all coils have passed the spark test, does the
engine start?
Ð
Refasten all
coils with
their screws
Go to Step 16
161. Remove the spark plugs from all cylinders.
2. Visually inspect the spark plug electrodes.
3. Replace any spark plugs with loose or missing
electrodes or cracked insulators.
Did your inspection reveal any spark plugs exhibiting
excessive fouling?
Ð
Correct the
fouling
condition
Go to Step 17
17Refer to Engine Mechanical Diagnosis to diagnose the
following conditions:

Faulty or incorrect camshaft drive belts

Leaking or sticky valves or rings

Excessive valve deposits

Loose or worn rocker arms

Weak valve springs

Incorrect valve timing

Leaking head gasket
Is the action complete?
ÐVerify repairGo to Step 19
18Observe the ªEngine Speedº data display on the scan
tool while cranking the engine.
Is the engine RPM indicated? (If the scan tool is
normally powered from the cigarette lighter socket, and
if the scan tool display goes blank while cranking the
engine, it will be necessary to power the scan tool
directly from the vehicle battery.)
ÐGo to Step 19Go to Step 28
191. Disconnect the 7-pin gray connector at the rear of
the air filter beneath the point where the air duct
attaches to the MAF sensor.
2. Ignition ªON.º
3. Using a test light connected to ground, probe the
ignition terminal at the PCM (female) side of the
7-pin connector.
Is the test light ªON?º
ÐGo to Step 20Go to Step 26

6E±264
ENGINE DRIVEABILITY AND EMISSIONS
Hard Start Symptom

 
StepNo Ye s Value(s) Action
121. Remove spark plugs. Check for wet plugs, cracks,
wear, improper gap, burned electrodes, or heavy
deposits. Refer to
Electronic Ignition System.
NOTE: If spark plugs are gas or oil fouled, the cause of
the fouling must be determined before replacing the
spark plugs.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 13
131. Check for a loose ignition coil ground.
Refer to
Electronic Ignition System.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 14
141. Remove the ignition coils and check the ignition
coils for cracks or carbon tracking.
2. If a problem is found, replace affected coil(s) as
necessary.
Was a problem found?
ÐVerify repairGo to Step 15
151. Check IAC operation. Perform the procedure in the
DTC P0506, Step 6 diagnostic table.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 16
161. Check for the following engine mechanical
problems (refer to
Engine Mechanical):

Low compression

Leaking cylinder head gaskets

Worn or incorrect camshaft

Camshaft drive belt slipped or stripped
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 17
171. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:

Visual/physical inspection

Tech 2 data

Freeze Frame data/Failure Records buffer

All electrical connections within a suspected
circuit and/or system.
3. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repair
Contact
Technical
Assistance

6E±266
ENGINE DRIVEABILITY AND EMISSIONS
Surges and/or Chuggles Symptom

 
StepNo Ye s Value(s) Action
101. Check for proper ignition voltage output with spark
tester J 26792 (ST-125). Refer to
Electric Ignition
System
for procedure.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 11
111. Check for a loose ignition coil ground.
Refer to
Electric Ignition System.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 12
121. Check the ignition coils for cracks or carbon
tracking.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 13
131. Remove the spark plugs and check for wet plugs,
cracks, wear, improper gap, burned electrodes, or
heavy deposits. Refer to
Electronic Ignition
System
.
NOTE: If spark plugs are gas or oil fouled, the cause of
the fouling must be determined before replacing the
spark plugs.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 14
141. Check the injector connections.
2. If any of the injector connectors are connected to an
incorrect cylinder, correct as necessary.
Was a problem found?
ÐVerify repairGo to Step 15
151. Check PCM grounds for the cleanliness, tightness
and proper locations. Refer to the PCM wiring
diagrams in
Electrical Diagnosis.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 16
161. Check MAF sensor connections.
2. If a problem is found, replace the faulty terminals as
necessary. Refer to
Electrical Diagnosis for wiring
repair procedures.
Was a problem found?
ÐVerify repairGo to Step 17
171. Visually/physically check vacuum hoses for splits,
kinks, and proper connections and routing as
shown on the ªVehicle Emission Control
Informationº label.
2. If a problem is found, repair as necessary.
Was a problem found?
ÐVerify repairGo to Step 18