1A-9 Engine General Information and Diagnosis:
Diagnostic Information and Procedures
Engine Symptom Diagnosis
B817H21104001
Condition Possible cause Correction / Reference Item
Engine will not start or is
hard to start
(Compression too low)
Valve clearance out of adjustment. Adjust.
Worn valve guides or poor seating of
valves.
Repair or replace.
Mistimed valves. Adjust.
Excessively worn piston rings. Replace.
Worn-down cylinder bores. Replace.
Starter motor cranks too slowly. Refer to “Starting System Diagram in Section
1I (Page 1I-1)”.
Poor seating of spark plugs. Retighten.
Engine will not start or is
hard to start (Plugs not
sparking)
Fouled spark plugs. Clean.
Wet spark plugs. Clean and dry.
Defective ignition coil/plug cap. Replace.
Defective CKP sensor. Replace.
Defective ECM. Replace.
Open-circuited wiring connections. Repair or replace.
Engine will not start or is
hard to start (No fuel
reaching the intake
manifold)
Clogged fuel filter or fuel hose. Clean or replace.
Defective fuel pump. Replace.
Defective fuel pressure regulator. Replace.
Defective fuel injectors. Replace.
Defective fuel pump relay. Replace.
Defective ECM. Replace.
Open-circuited wiring connections. Check and repair.
Engine will not start or is
hard to start (Incorrect
fuel/air mixture)
Defective fuel pump. Replace.
Defective fuel pressure regulator. Replace.
Defective TP sensor. Replace.
Defective CKP sensor. Replace.
Defective IAP sensor. Replace.
Defective ECM. Replace.
Defective ECT sensor. Replace.
Defective IAT sensors. Replace.
Engine idles poorly Valve clearance out of adjustment. Adjust.
Poor seating of valves. Replace or repair.
Defective valve guides. Replace.
Worn down camshafts. Replace.
Too wide spark plug gaps. Adjust or replace.
Defective ignition coil/plug gap. Replace.
Defective CKP. Replace.
Defective ECM. Replace.
Defective TP sensor. Replace.
Defective fuel pump. Replace.
Defective ISC valve. Replace.
Imbalanced throttle valve. Adjust.
Damaged or cranked vacuum hose. Replace.
Engine stalls often
(Incorrect fuel/air mixture)
Defective IAP sensor or circuit. Repair or replace.
Clogged fuel filter. Clean or replace.
Defective fuel pump. Replace.
Defective fuel pressure regulator. Replace.
Damaged or cracked vacuum hose. Replace.
Defective ECT sensor. Replace.
Defective thermostat. Replace.
Defective IAT sensors. Replace.
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