ISUZU TROOPER 1998 Service Repair Manual

6A±15
ENGINE MECHANICAL
Condition CorrectionPossible cause
Oil leaking into combustion
chambers due topoor seal in valve
Valve stem oil seal defectiveReplace
chambers due to oor seal in valve
systemValve stem or valve guide wornReplace valve and valve guide
Oil leaking into combustion
chambers due to poor seal in cylinder
t
Cylinders and pistons worn
excessivelyReplace cylinder body assembly and
pistons
partsPiston ring gaps incorrectly
positionedCorrect
Piston rings set with wrong side upCorrect
Piston ring stickingReplace cylinder body assembly and
pistons
Piston ring and ring groove wornReplace pistons and others
Return ports in oil rings cloggedClean piston and replace rings
Positive Crankcase Ventilation
System malfunctioningPositive Crankcase Ventilation Valve
cloggedClean
OthersImproper oil viscosityUse oil of recommended S.A.E.
viscosity
Continuous high speed driving
and/or severe usage such as trailer
towingContinuous high speed operation
and/or severe usage will normally
cause increased oil consumption
Fuel Consumption Excessive
ConditionPossible causeCorrection
Trouble in fuel systemMixture too rich or too lean due to
trouble in fuel injection systemRefer to ªAbnormal Combustionº
Fuel cut function does not workRefer to ªAbnormal Combustionº
Trouble in ignition systemMisfiring or abnormal combustion
due to trouble in ignition systemRefer to ªHard Startº or ªAbnormal
Combustionº
OthersEngine idle speed too highReset Idle Air Control Valve
Returning of accelerator control
sluggishCorrect
Fuel system leakageCorrect or replace
Clutch slippingCorrect
Brake dragCorrect
Selection of transmission gear
incorrectCaution operator of incorrect gear
selection
Excessive Exhaust Gas
Recirculation flow due to trouble in
Exhaust Gas Recirculation systemRefer to ªAbnormal Combustionº

6A±16
ENGINE MECHANICAL
Lubrication Problems
ConditionPossible causeCorrection
Oil pressure too lowWrong oil in useReplace with correct engine oil
Relief valve stickingReplace
Oil pump not operating properlyCorrect or replace
Oil pump strainer cloggedClean or replace strainer
Oil pump wornReplace
Oil pressure gauge defectiveCorrect or replace
Crankshaft bearing or connecting
rod bearing wornReplace
Oil contaminationWrong oil in useReplace with correct engine oil
Oil filter cloggedReplace oil filter
Cylinder head gasket damageReplace gasket
Burned gases leakingReplace piston and piston rings or
cylinder body assembly
Oil not reaching valve systemOil passage in cylinder head or
cylinder body cloggedClean or correct
Engine Oil Pressure Check
1. Check for dirt, gasoline or water in the engine oil.
a. Check the viscosity of the oil.
b. Change the oil if the viscosity is outside the
specified standard.
c. Refer to the ªMaintenance and Lubricationº section
of this manual.
2. Check the engine oil level.
The level should fall somewhere between the ªADDº
and the ªFULLº marks on the oil level dipstick.
If the oil level does not reach the ªADDº mark on the
oil level dipstick, engine oil must be added.3. Remove the oil pressure unit.
4. Install an oil pressure gauge.
5. Start the engine and allow the engine to reach normal
operating temperature (About 80
C).
6. Measure the oil pressure.
Oil pressure should be:
392±550 kPa (56.9±80.4 psi) at 3000 rpm.
7. Stop the engine.
8. Remove the oil pressure gauge.
9. Install the oil pressure unit.
10. Start the engine and check for leaks.

6A±17
ENGINE MECHANICAL
Malfunction Indicator Lamp
The instrument panel ªCHECK ENGINEº Malfunction
Indicator Lamp (MIL) illuminates by self diagnosticsystem when the system checks the starting of engine, or
senses malfunctions.
Condition
Possible causeCorrection
ªCHECK ENGINEº MIL does not
illuminate at the starting of engine
Bulb defectiveReplace
illuminate at the starting of engineMIL circuit openCorrect or replace
Command signal circuit to operate
self diagnostic system shortedCorrect or replace
Engine Control Module (PCM) cable
loosely connected, disconnected or
defectiveCorrect or replace
PCM defectiveReplace
ªCHECK ENGINEº MIL illuminates,
and stays onDeterioration of heated oxygen
sensor internal elementReplace
Heated oxygen sensor connector
terminal improper contactReconnect properly
Heated oxygen sensor lead wire
shortedCorrect
Heated oxygen sensor circuit openCorrect or replace
Deterioration of engine coolant
temperature sensor internal elementReplace
Engine coolant temperature sensor
connector terminal improper contactReconnect properly
Engine coolant temperature sensor
lead wire shortedCorrect
Engine coolant temperature sensor
circuit openCorrect or replace
Throttle position sensor open or
shorted circuitsCorrect or replace
Deterioration of crankshaft position
sensorReplace
Crankshaft position sensor circuit
open or shortedCorrect or replace
Vehicle speed sensor circuit openCorrect or replace
Manifold absolute pressure sensor
circuit open or shortedCorrect or replace
Intake air temperature sensor circuit
open or shortedCorrect or replace
Fuel injector circuit open or shortedCorrect or replace
PCM driver transistor defectiveReplace PCM
Malfunctioning of PCM RAM
(Random Access Memory) or ROM
(Read Only Memory)Replace PCM

6A±18
ENGINE MECHANICAL
Cylinder Head Cover LH
Removal
1. Disconnect battery ground cable.
2. Drain engine coolant from faucet bottom of radiator.
3. Remove engine cover from the dowels on the
common chamber.
F06RW018
4. Remove air cleaner duct assembly (3) and air cleaner
element (4).
130RW001
Legend
(1) Positive Crankcase Ventilation Hose Connector
(2) Intake Air Temperature Sensor
(3) Air Cleaner Duct Assembly
(4) Air Cleaner Element
(5) Mass Air Flow Sensor
NOTE: Disconnect the mass air flow (MAF) sensor
connector, intake air temperature (IAT) sensor connector,
and positive crankcase ventilation (PCV) hose before
hand the air cleaner duct assembly is removed.5. Disconnect following wiring connectors and bonding
cable:

Manifold Absolute Pressure (MAP) sensor

Vacuum Switching Valve (VSV) for Induction Air
Control Valve (IACV) actuator

Ignition coils for left bank

Fuel injectors for left bank

Idle air control (IAC) valve

Throttle position sensor (TPS)

Bonding cable

Others as necessitated
6. Disconnect following vacuum hoses:

Brake master VAC

Canister

VSV for IACV actuator

Duty solenoid valve

PCV
7. Disconnect radiator upper and lower hoses
8. Remove engine harness from the cylinder head
cover.
9. Remove the upper fan guide.
10. Remove cooling fan and clutch assembly.
11. Remove drive belt by pushing down the auto
tensioner using spanner as illustrated.
F06RW019

6A±19
ENGINE MECHANICAL
Legend
(1) Crankshaft Pulley
(2) Generator
(3) Auto Tensioner
(4) Idle Pulley
(5) Cooling Fan Pulley
(6) Power Steering Oil Pump
(7) Drive Belt
(8) Air Conditioner Compressor
12. Remove power steering oil pump pulley.
13. Remove fan pulley and bracket assembly.
14. Remove idle pulley assembly.
15. Remove auto tensioner assembly.
16. Remove crankshaft pulley using 5±8840±0133±0
crankshaft holder.
17. Remove timing belt covers from the right bank side to
the left bank side in order.
18. Remove ignition coil assemblies for the left side bank.
060RW018
Legend
(1) Ignition Coil Connectors
(2) Bolts
(3) Ignition Coil Assemblies
19. Remove cylinder head cover assembly.
Installation
1. Install cylinder head cover.

Clean the sealing surface of cylinder head and
cylinder head cover to remove oil and sealing
materials completely.

Apply sealant (TB-1207B or equivalent) of bead
diameter 2-3 mm at eight place of arched area of
camshaft bracket on front and rear sides.
The cylinder head cover must be installed within 5
minutes after sealant application to prevent
premature hardening of sealant.
014RW144

Tighten bolts to the specified torque.
Torque : 9 N´m (0.9 Kg´m/78 lb in)
010RW008
2. Install ignition coil assemblies and tighten the fixing
bolts to the specified torque.
Torque : 4 N´m (0.4 Kg´m/35 lb in)
3. Install timing belt covers from left bank side to right
bank side, and tighten the fixing bolts and nut to the
specified torque.
Torque : 19 N´m (1.9 Kg´m/14 lb ft)
4. Install crankshaft pulley and tighten the fixing bolt
using 5±8840±0133±0 crankshaft holder to the
specified torque.
Torque : 167 N´m (17.0 Kg´m/123 lb ft)

6A±20
ENGINE MECHANICAL
5. Install auto tensioner assembly and tighten the fixing
bolts to the specified torque.
Torque :
Shorter Bolt : 20 N´m (2.0 Kg´m/14 lb ft)
Longer Bolt : 39 N´m (4.0 Kg´m/29 lb ft)
6. Install idle pulley and bracket assembly and tighten
the fixing bolt to the specified torque.
Torque : 52 N´m (5.3 Kg´m/38 lb ft)
7. Install fan pulley and bracket assembly and tighten
the fixing bolts and nut to the specified torque.
Torque : 22 N´m (2.2 Kg´m/16 lb ft)
8. Install power steering oil pump pulley and tighten the
fixing bolt to the specified torque.
Torque : 78 N´m (8.0 Kg´m/58 lb ft)
9. Install drive belt by pushing down the auto tensioner
using spanner as shown in the removal step of drive
belt.
10. Install cooling fan and clutch assembly and tighten
the fixing bolts to the specified torque.
Torque : 10 N´m (1.0 Kg´m/87 lb in)
11. Install upper fan guide and clip both side and tighten
the fixing bolts to the specified torque.
Torque : 4 N´m (0.4 Kg´m/35 lb in)
12. Install engine harness and tighten the fixing bolts of
the retaining clip and bracket to the specified torque.
Torque : 4 N´m (0.4 Kg´m/35 lb in)
13. Connect radiator upper and lower hoses and clip
them securely.
14. Connect vacuum hoses of those which were
disconnected in the removal step.
15. Connect wiring connectors and bonding cable of
those which were disconnected in the removal step.
16. Install air cleaner element and air cleaner duct
assembly, and clip the both end securely.
17. Connect MAF sensor connector, IAT sensor
connector and PCV hose.
18. Install engine cover mating with the dowels.

6A±21
ENGINE MECHANICAL
Cylinder Head Cover RH
Removal
1. Disconnect battery ground cable.
2. Remove battery from the vehicle.
3. Drain engine coolant from faucet bottom of radiator.
4. Remove engine cover from the dowels on the
common chamber.
F06RW018
5. Remove air cleaner duct assembly (3) and air cleaner
element (4).
130RW001
Legend
(1) Positive Crankcase Ventilation Hose Connector
(2) Intake Air Temperature Sensor
(3) Air Cleaner Duct Assembly
(4) Air Cleaner Element
(5) Mass Air Flow Sensor
NOTE: Disconnect the mass air flow (MAF) sensor
connector, intake air temperature (IAT) sensor connector,
and positive crankcase ventilation (PCV) hose before
hand the air cleaner duct assembly is removed.
6. Disconnect following wiring connectors and bonding
cable:

Exhaust Gas Recirculation (EGR) valve

Fuel injectors for right bank

Ignition coils for right bank

Bonding cable

Othres as necessitated
7. Disconnect radiator upper and lower hoses.
8. Remove engine harness from the cylinder head
cover.
9. Remove the upper fan guide.
10. Remove cooling fan and clutch assembly.
11. Remove drive belt by pushing down the auto
tensioner using spanner as illustrated.
F06RW019
Legend
(1) Crankshaft Pulley
(2) Generator
(3) Auto Tensioner
(4) Idle Pulley
(5) Cooling Fan Pulley
(6) Power Steering Oil Pump
(7) Drive Belt
(8) Air Conditioner Compressor
12. Remove fan pulley and bracket assembly.
13. Remove idle pulley assembly.
14. Remove auto tensioner assembly.
15. Remove crankshaft pulley using 5±8840±0133±0
crankshaft holder.

6A±22
ENGINE MECHANICAL
16. Remove timing belt covers for right bank side.
17. Reomve timing belt covers for right bank side.
060RW001
Legend
(1) Ignition Coil Connectors
(2) Bolts
(3) Ignition Coil Assemblies
18. Remove ignition coil assemblies for the right side
bank.
19. Remove cylinder head cover assembly.
Installation
1. Install cylinder head cover.

Clean the sealing surface of cylinder head and
cylinder head cover to remove oil and sealing
materials completely.

Apply sealant (TB-1207B or equivalent) of bead
diameter 2-3 mm at eight place of arched area of
camshaft bracket on front and rear sides.

The cylinder head cover must be installed within 5
minutes after sealant application before the sealant
hardens.
014RW143

Tighten bolts in turn to the specified torque.
Torque : 8.8 N´m (0.9 Kg´m/78 lb in)
010RW007
2. Install ignition coil assemblies and tighten the fixing
bolts to the specified torque.
Torque : 4 N´m (0.4 Kg´m/35 lb in)
3. Install timing belt cover and tighten the fixing bolts and
nut to the specified torque.
Torque : 19 N´m (1.9 Kg´m/14 lb ft)
4. Install crankshaft pulley and tighten the fixing bolt
using 5±8840±0133±0 crankshaft holder to the
specified torque.
Torque : 167 N´m (17 Kg´m/123 lb ft)
5. Install auto tensioner assembly and tighten the fixing
bolts to the specified torque.
Torque :
Shorter Bolt : 20 N´m (2.0 Kg´m/14.8 lb ft)
Longer Bolt : 39 N´m (4.0 Kg´m/28.8 lb ft)

6A±23
ENGINE MECHANICAL
6. Install idle pulley assembly and tighten the fixing bolt
to the specified torque.
Torque : 52 N´m (5.3 Kg´m/38.4 lb ft)
7. Install fan pulley and bracket assembly and tighten
the fixing bolts and nut to the specified torque.
Torque : 22 N´m (2.2 Kg´m/16.2 lb ft)
8. Install drive belt by pushing down the auto tensioner
using spanner as shown in the removal step of drive
belt.
9. Install cooling fan clutch assembly and tighten the
fixing bolts to the specified torque.
Torque : 10 N´m (1.0 Kg´m/88.5 lb in)
10. Install upper fan guide and clip both side and tighten
the fixing bolts to the specified torque.
Torque : 4 N´m (0.4 Kg´m/35.4 lb in)
11. Install engine harness and tighten the fixing bolts of
the retaining clip and brackets to the specified torque.
Torque : 4 N´m (0.4 Kg´m/35.4 lb in)
12. Connect radiator upper and lower hoses and clip
them securely.
13. Connect wiring connectors and bonding cable of
those which were disconnected in the removal step.
14. Install air cleaner element and air cleaner duct
assembly, and the clip both end securely.
15. Connect MAF sensor connector, IAT sensor
connector and PCV hose.
16. Install engine cover mating with the dowels.

6A±24
ENGINE MECHANICAL
Common Chamber
Removal
1. Disconnect battery ground cable.
2. Remove air cleaner duct assembly.
130RW001
Legend
(1) Positive Crankcase Ventilation Hose Connector
(2) Intake Air Temperature Sensor
(3) Air Cleaner Duct Assembly
(4) Air Cleaner Element
(5) Air Flow Sensor
3. Disconnect accelerator pedal cable from throttle body
and cable bracket.
4. Disconnect vacuum booster hose from common
chamber.
5. Disconnect connector from manifold absolute
pressure sensor, idle air control valve, throttle
position sensor, solenoid valve, electric vacuum
sensing valve, and EGR valve.
6. Disconnect vacuum hose on canister VSV and
positive crankcase ventilation hose, fuel rail
assembly with pressure control valve bracket.
7. Remove ventilation hose from throttle valve and
intake duct and remove water hose.
8. Remove the four throttle body fixing bolts.
9. Remove exhaust gas recirculation valve assembly
fixing bolt and nut on common chamber and remove
EGR valve assembly.
10. Remove two bolts from common chamber rear side
for remove fuel hose bracket.
11. Remove common chamber four bolts and four nuts
then remove the common chamber.
025RW001
Legend
(1) Common Chamber
(2) Throttle Valve Assembly
(3) Bolt
Installation
1. Install common chamber and tighten bolts and nuts to
the specified torque.
Torque :
Bolt : 25 N´m (2.5 Kg´m/18 lb ft)
Nut : 25 N´m (2.5 Kg´m/18 lb ft)
2. Install fuel hose bracket and tighten bolts to specified
torque.
Torque : 10 N´m (1.0 Kg´m/89 lb in)
3. Install exhaust gas recirculation valve assembly and
tighten bolt and nut to the specified torque.
Torque : 25 N´m (2.5 Kg´m/18 lb ft)
4. Install throttle body and tighten bolts to the specified
torque.
Torque : 25 N´m (2.5 Kg´m/18 lb ft)
5. Install ventilating hose to throttle valve and intake
duct.
6. Connect vacuum hoses on canister VSV and positive
crankcase ventilation hose. Tighten bolts for fuel rail
assembly with pressure control valve bracket.
Torque : 25 N´m (2.5 Kg´m/18 lb ft)
7. Connect each connector without fail.
8. Connect vacuum booster hose.
9. Connect accelerator pedal cable.
Accelerator pedal cable adjustment
1. Loosen the adjusting nut and screw cap.
2. Pull outer cable while fully closing the throttle
valve.