Isuzu engine C22NE / 22LE / 20LE. Manual - part 67

 

  Index      Isuzu     Isuzu engine C22NE / 22LE / 20LE - service manual

 

Search            

 

 

 

 

 

 

 

  

 

Content   ..  65  66  67  68   ..

 

 

Isuzu engine C22NE / 22LE / 20LE. Manual - part 67

 

 

DRIVEABILITY AND EMISSIONS  6E1-97

Dieseling, Run-On Symptom

Step

Action

Value(s)

Yes

No

DEFINITION: Engine continues to run after key is turned OFF, but runs very rough. If engine runs smoothly, check

the ignition switch and adjustment.

1

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 the ignition feed

circuit.

Was a problem found?

-

Verify repair

Go to Step 5

5

1.  Review all the 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.
• Scan Tool data.
• All electrical connections within a suspected circuit

and/or system.

Was a problem found?

-

Verify repair

Contact

Technical

Assistance

6E1-98  DRIVEABILITY AND EMISSIONS

Backfire Symptom

Step

Action

Value(s)

Yes

No

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

1

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

Check for proper ignition voltage output with the spark

tester (Use commercially available tool).

Was a problem found?

-

Verify repair

Go to Step 5

5

1.  Remove the spark plugs and check for gas or oil

fouling cracks, wear, improper gap, burned electrodes

of heavy deposits.

2.  If spark plugs are fouled, the cause of fouling must be

determined before replacing the spark plugs.

Was a problem found?

-

Verify repair

Go to Step 6

6

1.  Visually/Physically inspect the secondary ignition wires.

Check for the following conditions:

• Verify that all ignition wire resistance are less than the

specified value.

• Verify that ignition wires are correctly routed to eliminate

cross-firing.

• Verify that ignition wires are not arcing to ground.

Spraying the secondary ignition wires with a light mist of

water may help locate an intermittent problem.

Was a problem found?

-

Verify repair

Go to Step 7

7

Check for an intermittent ignition system malfunction:
• Intermittent CKP 58X signal.
• Intermittent ignition feed circuit or sensor ground circuit

to the crankshaft position sensor.

Was a problem found?

-

Verify repair

Go to Step 8

8

Refer to Fuel System Diagnosis to determine if there is a

problem with fuel delivery.

Was a problem found?

-

Verify repair

Go to Step 9

9

Check for the following engine mechanical problems:
• Low compression
• Leaking cylinder head gasket
• Worn or incorrect camshaft
• Incorrect valve timing
• Sticking or leaking valves
• Camshaft drive belt slipped or stripped.
Was a problem found?

-

Verify repair

Go to Step 10

DRIVEABILITY AND EMISSIONS  6E1-99

Backfire Symptom (Cont'd)

Step

Action

Value(s)

Yes

No

10

Check the intake and exhaust manifold(s) for casting

flash. Refer to Engine Mechanical.

Was a problem found?

-

Verify repair

Go to Step 11

11

1.  Review all the 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.
• Scan Tool data.
• All electrical connections within a suspected circuit

and/or system.

Was a problem found?

-

Verify repair

Contact

Technical

Assistance

6E1-100  DRIVEABILITY AND EMISSIONS

Cuts Out, Misses Symptom

Step

Action

Value(s)

Yes

No

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

increases.

1

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/

Physical

Check

4

Check the ECM grounds to verify that they are clean and

tight. Refer to the ECM wiring diagrams in Electrical

Diagnosis.

Was a problem found?

-

Verify repair

Go to Step 5

5

Monitor  "02 Status"  on the Scan Tool.

Is the  "02 Status"  in the rich condition (If applicable) ?

Go to Step 6

Go to Step 7

6

Check items that can cause the engine to run rich.

Refer to  "Diagnostic Aids"  in Diagnostic Trouble Code 45

(If applicable).

Was a problem found?

-

Verify repair

Go to Step 9

7

Is the "02 Status" significantly in the lean condition (If

applicable)?

-

Go to Step 8

Go to Step 9

8

Check items that can cause the engine to run lean.

Refer to Diagnostic Aids in Diagnostic Trouble Code 44 (If

applicable).

Was a problem found?

-

Verify repair

Go to Step 9

9

1.  Check for incorrect idle speed. Ensure that the

following conditions are present:
• Engine fully warm.
• Accessories are OFF.

2.  Using a Scan Tool, 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

 

 

 

 

 

 

 

Content   ..  65  66  67  68   ..