TROUBLESHOOTING 3-3
Complaint
Symptom and possible causes
Remedy
Engine idles poorly.
• Valve clearance out of adjustment
• Valve timing out of adjustment
• Poor seating of valves
• Worn valve guide
• Worn down camshafts
• Incorrect spark plug gap
• Defective ignition coil/plug cap
• Defective CKP sensor
• Defective ECM
• Defective TP sensor
• Defective fuel pump
• Insufficient throttle cable play
Adjust
Adjust
Repair
Replace
Replace
Adjust
Replace
Replace
Replace
Adjust or replace
Replace
Adjust
Engine stalls often.
Incorrect fuel/air mixture
• Defective IAP sensor or circuit
• Clogged fuel filter
• Defective fuel pump
• Defective fuel pressure regulator
• Defective ECT sensor
• Defective IAT sensor
Fuel injector improperly operating
• Defective fuel injector
• Defective ECM
• Open or short circuited wiring connections
• Defective magneto
Control circuit or sensor improperly operating
• Defective ECM
• Defective fuel pressure regulator
• Defective TP sensor
• Defective CKP sensor
• Defective ECT sensor
• Defective IAT sensor
• Defective TO sensor
Engine internal parts improperly operating
• Fouled spark plug
• Defective CKP sensor or ECM
• Clogged fuel hose
• Valve clearance out of adjustment
Repair or replace
Replace
Replace
Replace
Replace
Replace
Replace
Replace
Repair or replace
Replace
Replace
Replace
Replace
Replace
Replace
Replace
Replace
Clean
Replace
Clean
Adjust