TEST NTC-12ACHECKING THE ENGINE MECHANICAL SYSTEMS
Perform TEST NTC-1A Before Proceeding
At this point in the diagnostic test procedure, you have determined that all of theengine electrical
systemsare operating as designed; therefore, theyare not the cause of the driveability problem.
The following additional items should be checked as possible mechanical causes of the problem.
1. ENGINE VALVE TIMING- must be within specifications
2. ENGINE COMPRESSION- must be within specifications
3. CAMSHAFT LOBES- check for abnormal wear
4. ENGINE SPEED SENSOR PICK-UP- check flywheel slots for debris/deterioration
5. ENGINE EXHAUST SYSTEM- must be free of any restrictions
6. ENGINE DRIVE SPROCKET- must be properly positioned
7. POWER BRAKE BOOSTER- no internal vacuum leaks
8. FUEL- must be free of contamination
9. FUEL INJECTOR- plugged or restricted injector
10. FUEL INJECTION PUMP- must be properly timed
NOTE:Always look for any Technical Service Bulletins that may relate to the problem.
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