Cause
|
Correction
|
Abnormalities, severe cracking, bumps or missing areas in the
accessory drive belt
Abnormalities in the accessory drive system and/or components may
cause engine revolutions per minute (RPM) variations, noises
similar to a faulty lower engine, and also lead to a misfire
condition. A misfire code may be present without an actual misfire
condition.
|
Replace the drive belt.
|
Worn, damaged, or mis-aligned accessory drive components or
excessive pulley runout
A misfire code may be present without an actual misfire
condition.
|
Inspect the components, repair or replace as required.
|
Loose or improperly installed engine flywheel or crankshaft
balancer
A misfire code may be present without an actual misfire
condition.
|
Repair or replace the flywheel and/or balancer as required.
|
Worn piston rings
Oil consumption may or may not cause the engine to misfire.
|
| • |
Inspect the spark plugs for oil deposits. |
| • |
Perform cylinder leak down and compression testing
to determine the cause. |
| • |
Repair or replace as required. |
|
Worn crankshaft thrust bearings
Severely worn thrust surfaces on the crankshaft and/or thrust
bearing may permit fore and aft movement of the crankshaft, and
create a diagnostic trouble code (DTC) without an actual misfire
condition.
|
Replace the crankshaft and bearings as required.
|
