Isuzu Rodeo UE. Manual — part 420

6E2–435

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Dieseling, Run-On Symptom

Step

Action

Value(s)

Yes

No

1

DEFINITION:
Engine continues to run after key is turned “OFF,” but
runs very rough. If engine runs smooth, check ignition
switch and adjustment.

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to

Step 2

Go 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 4

Go to

Visual/Physic

al Check

4

1. Check for a short between B+ and any of the ignition

feed circuits.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to

Step 5

5

1. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no

malfunctions have been found, review/inspect the
following:

f

Visual/physical inspection

f

Tech 2 data

f

Freeze Frame data/Failure Records butter

f

All electrical connections within a suspected
circuit and/or system

3. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Contact

Technical

Assistance

6E2–436

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Backfire Symptom

Step

Action

Value(s)

Yes

No

1

DEFINITION:
Fuel ignites in the intake manifold, or in the exhaust
system, making a loud popping noise.

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to

Step 2

Go 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 4

Go to

Visual/Physic

al Check

4

1. Check for proper ignition voltage coil output with

spark tester J 26792 (ST-125). Refer to

Electronic

Ignition System for procedure.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to

Step 5

5

1. Remove 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. Refer to

DTC P0172 to determine the

cause of a rich condition or

Engine Mechanical for an oil

fouling condition.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to

Step 6

6

1. Visually/physically inspect the ignition coils for

cracks.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to

Step 7

7

1. Check for an intermittent ignition system

malfunction:

f

Intermittent CKP 58X signal.

f

Intermittent ignition feed circuit or sensor
ground circuit to the crankshaft position
sensor.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to

Step 8

8

1. Check the fuel pressure. Refer to

Fuel System

Pressure Test.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to

Step 9

6E2–437

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Backfire Symptom

(Cont'd)

Step

No

Yes

Value(s)

Action

9

1. Check for the following engine mechanical

conditions.

Refer to

Engine Mechanical for diagnosis

procedures:

f

Low compression

f

Sticking or leaking valves

f

Worn camshaft lobe(s)

f

Camshaft drive belt slipped or stripped

f

Incorrect valve timing

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to

Step 10

10

1. Check the intake and exhaust manifold(s) for

casting flash. Refer to

Engine Mechanical.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to

Step 11

11

1. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no

malfunctions have been found, review/inspect the
following:

f

Visual/physical inspection

f

Tech 2 data

f

Freeze Frame data/Failure Records butter

f

All electrical connections within a suspected
circuit and/or system.

3. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Contact

Technical

Assistance

6E2–438

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Cuts Out, Misses Symptom

Step

Action

Value(s)

Yes

No

1

DEFINITION:
Steady pulsation or jerking that follows engine speed;
usually more pronounced as engine load increases.

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to

Step 2

Go 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?

—

Go to

Step 13

Go to

Step 3

3

Was a visual/physical check performed?

—

Go to

Step 4

Go to

Visual/Physic

al Check

4

1. Check the PCM grounds for clearness, tightness

and proper routing. Refer to the PCM wiring
diagrams in

Electrical Diagnosis.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to

Step 5

5

Observe the long term fuel trim on the Tech 2.

Is the long term fuel trim significantly in the negative
range (rich condition)?

—

Go to

Step 6

Go to

Step 7

6

1. Check items that can cause the engine to run rich.

Refer to

Diagnostic Aids in DTC P0172 Diagnostic

Support.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to

Step 9

7

Is the long term fuel trim significantly in the positive
range (lean condition)?

—

Go to

Step 8

Go to

Step 9

8

1. Check items that can cause the engine to run lean.

Refer to

Diagnostic Aids in DTC P0171 Diagnostic

Support.

2. If a problem is found, repair as necessary.

Was a problem found?

—

Verify repair

Go to

Step 9

9

1. Check for incorrect idle speed. Ensure that the

following conditions are present:

f

The engine is fully warm.

f

The accessories are “off.”

2. Using a Tech 2, monitor the IAC position.

Is the IAC position within the specified values?

Between 5

and 50

counts

Go to

Step 11

Go to

Step 10