Isuzu 2000 Trooper Workshop Manual page 726

Troubleshooting Procedure
The slapping sound stops when spark plug on bad cylin-
der is shorted out.
Condition
Timing belt noise
Valve noise
Crankshaft noise
Engine knocking
Others
Possible cause
Timing belt tension is incorrect
Tensioner bearing defective
Timing belt defective
Timing pulley defective
Timing belt comes in contact with
timing cover
Valve clearance incorrect
Valve and valve guide seized
Valve spring broken or weakened
Valve seat off–positioned
Camshaft worn out
Crankshaft end play
(noise occurs when
engaged)
Preignition due to use of spark plugs
of inadequate heat range
Carbon deposits in combustion
chambers
Fuel too low in octane rating
Wide Open Throttle enrichment
system failure
Selection of transmission
incorrect
Engine overheating
Water pump defective
Drive belt slipping
ENGINE MECHANICAL
Replace pusher or adjust the tension
pulley or replace timing belt
Replace
Replace
Replace
Replace timing belt and timing cover
Replace adjusting shim
Replace valve and valve guide
Replace
Correct
Replace
excessive Replace thrust bearing
clutch is
Install Spark Plugs of adequate heat
range
Clean
Replace fuel
Refer to Section 6E
gear Caution operator of incorrect gear
selection
Refer to "Engine Lacks Power"
Replace
Replace auto tentioner or drive belt
6A–13
Correction