1A-7 Engine General Information and Diagnosis:
Diagnostic Information and Procedures
Engine Symptom Diagnosis
BA02J21104001
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 bore. Replace.
Starter motor cranks too slowly. Refer to “Starting System Diagram” in Section
1I (Page 1I-1).
Poor seating of spark plug. Retighten.
Broken, cracked, or damaged piston. Replace.
Defective automatic decomp. Clean or replace.
Engine will not start or is
hard to start (Plug not
sparking)
Fouled spark plug. Clean.
Wet spark plug. Clean and dry.
Incorrect spark plug gap. Replace.
Defective spark plug cap. Replace.
Defective ignition coil. Replace.
Open or short in high-tension cord. Replace.
Defective CKP sensor. Replace.
Defective ECM. Replace.
Open-circuited wiring connections. Repair or replace.
Defective magneto. Replace.
Engine will not start or is
hard to start (No fuel
reaching the intake
manifold)
Clogged fuel feed hose or fuel delivery
pipe.
Clean or replace.
Defective fuel pump. Replace.
Defective fuel injector. Replace.
Defective ECM. Replace.
Open-circuited wiring connections. Check and repair.
Defective TO sensor. Replace.
Engine will not start or is
hard to start (Incorrect
fuel/air mixture)
Defective fuel pump. Replace.
TP sensor out of adjustment. Adjust.
Defective TP sensor. Replace.
Defective CKP sensor. Replace.
Defective IAP sensor. Replace.
Defective ECM. Replace.
Defective ECT sensor. Replace.
Defective IAT sensor. Replace.
Engine idles poorly Valve clearance out of adjustment. Adjust.
Valve timing out of adjustment. Adjust.
Poor seating of valves. Replace or repair.
Worn valve guides. Replace.
Worn camshaft. Replace.
Incorrect spark plug gap. Replace.
Defective ignition coil. Replace.
Defective fuel pump. Replace.
Defective CKP sensor. Replace.
Defective ECM. Replace.
Defective TP sensor. Replace.
Insufficient throttle cable play. Adjust.
Engine stalls often
(Incorrect fuel/air mixture)
Defective IAP sensor or circuit.
Repair or replace.
De
fective fuel pump. Replace.
Defective ECT sensor. Replace.
Defective IAT sensor. Replace.
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