Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 873

6E–516

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Symptoms

Default Section(s)

Initial Diagnosis

Surges and/or Chuggles

1. OBD system check.
2. ETC system check.
3. Heated oxygen sensors.
4. Fuel system diagnosis.
5. Ignition system.

Calibration ID/Service Bulletins,
Ignition System Check,
Generator Output, Exhaust
System Diagnosis, 4L30-E
System Test

Lack of Power, Sluggish or Spongy

1. OBD system check.
2. ETC system check.
3. Fuel system diagnosis.
4. Ignition system.
5. EGR operation.
6. EGR system check.

Refer to 

Exhaust System in

Engine Exhaust, TCC Operation,
Calibration ID/Service Bulletins

Detonation/Spark Knock

1. OBD system check.
2. Transmission range switch.
3. EGR operation.
4. EGR system check.
5. TCC operation.
6. Fuel system diagnosis.
7. Ignition system.
8. ION sensing module check.

TCC operation, Cooling System,
Ignition System Check,
Calibration ID/Service Bulletins

Rough, Unstable, or Incorrect Idle,
Stalling

1. OBD system check.
2. ETC system check.
3. Fuel injector and fuel injector

balance test.

4. EVAP emission canister purge

valve check.

5. Ignition system.
6. EGR operation.

MAP Output Check, Throttle
Linkage, EGR System Check,
A/C Clutch Control Circuit
Diagnosis, Crankcase Ventilation
System, Calibration ID/Service
Bulletins, Generator Output
Voltage (refer to 

Chassis

Electrical), Exhaust Diagnosis

Poor Fuel Economy

1. OBD system check.
2. Careful visual/physical inspection.
3. Ignition system.
4. Cooling system.

TCC Operation, Exhaust System
(refer to 

Engine Exhaust)

Hesitation, Sag, Stumble

1. OBD system check.
2. ETC system check.
3. TP.
4. MAP output check.
5. Fuel system diagnosis.
6. Fuel injector and fuel injector

balance test.

7. EVAP emission canister purge

valve.

8. Ignition system.

EGR Operation, EGR System
Check, Generator Output
Voltage (refer to 

Chassis

Electrical), Calibration ID/Service
Bulletins, Ignition System Check

Cuts Out, Misses

1. OBD system check.
2. Cylinder balance test.
3. ETC system check.

Ignition System Check

Engine Cranks But Will Not Run

1. OBD system check.

Fuel System Electrical
Diagnosis, Fuel System
Diagnosis, Fuel Injector and Fuel
Injector Balance Test.

6E–517

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Symptoms

Default Section(s)

Initial Diagnosis

Excessive Exhaust Emissions or
Odors

1. OBD system check.
2. Emission test.
3. Cooling system.
4. Fuel system diagnosis.
5. Fuel injector and fuel injector

balance test.

6. EVAP emission canister purge

valve.

7. Crankcase ventilation system.
8. Ignition system.
9. MAP output check.

EGR System Check, Exhaust
Diagnosis, Calibration ID/Service
Bulletins

Dieseling, Run-On

1. OBD system check.
2. Careful visual/physical inspection.
3. Fuel system diagnosis.

—

Backfire

1. OBD system check.
2. Ignition system.
3. Fuel system diagnosis.
4. Fuel injector and fuel injector

balance test.

5. EGR operation, EGR system

check.

Exhaust System Diagnosis,
Intake Casting Flash, Ignition
System Check

Misfire

1. OBD system check.
2. Ignition system.
3. Fuel system diagnosis.
4. Fuel injector and fuel injector

balance test.

Vibrations, Transmission,
Driveshaft and Axle

Catalyst Monitor

1. OBD system check.
2. Careful visual/physical inspection.
3. Heated oxygen sensors.

Exhaust System

Fuel Trim

1. OBD system check.
2. Careful visual/physical inspection.
3. Fuel system diagnosis.
4. Heated oxygen sensors, MAF

sensors.

Exhaust System Intake Air
System

Evaporative Emissions

1. OBD system check.
2. Careful visual/physical inspection.
3. Fuel system diagnosis.

—

Heated Oxygen Sensors

1. OBD system check.
2. Careful visual/physical inspection.

Exhaust System

6E–518

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

On Vehicle Service  Crankshaft

Position (CKP) Sensor

Removal Procedure

1. Disconnect the negative battery cable.
2. Disconnect the electrical connector to the CKP

sensor.

3. Remove one bolt and the CKP sensor from the right

side of the engine block, just behind the mount.

NOTE: Use caution to avoid any hot oil that might drip
out.

TS22909

Inspection Procedure

1. Inspect the sensor O-ring for cracks or leaks.
2. Replace the O-ring if it is worn or damaged.
3. Lubricate the new O-ring with engine oil.
4. Install the lubricated O-ring.

Installation Procedure

1. Install the CKP sensor in the engine block.
2. Install the CKP sensor mounting bolt.

Tighten

D

Tighten the mounting bolt to 9 N·m (78 lb in.).

TS22909

3. Connect the electrical connector to the CKP sensor.
4. Connect the negative battery cable.

Engine Coolant Temperature

(ECT) Sensor

Removal Procedure

NOTE: Care must be taken when handling the engine
coolant temperature (ECT) sensor.  Damage to the ECT
sensor will affect proper operation of the fuel injection
system.

1. Disconnect the negative battery cable.
2. Drain the radiator coolant.  Refer to 

Draining and

Refilling Cooling System in Engine Cooling section.

3. Disconnect the electrical connector.

014RY00001

6E–519

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

4. Remove the ECT sensor from the coolant crossover.

014RY00002

Installation Procedure

1. Apply sealer or the equivalent to the threads of the

ECT sensor.

2. Install the ECT sensor in the coolant crossover.

Tighten

D

Tighten the ECT sensor to 30 N·m (22 lb ft.).

014RY00002

3. Connect the electrical connector.

014RY00003

4. Fill the radiator with coolant.  Refer to 

Draining and

Refilling Cooling System in Engine Cooling section.

5. Connect the negative battery cable.

Heated Oxygen Sensor (HO2S)

Removal Procedure

1. Disconnect the negative battery cable.
2. Locate the four oxygen sensors.

060RW008