SERVICING INFORMATION 10-7
Complaint
Symptom and possible causes
Remedy
Engine lacks power
Defective engine internal/electrical parts
1. Loss of valve clearance
2. Weakened valve springs
3. Valve timing out of adjustment
4. Worn piston rings or cylinders
5. Poor seating of valves
6. Fouled spark plugs
7. Incorrect spark plugs
8. Clogged fuel injectors
9. TP sensor out of adjustment
10. Clogged air cleaner element
11. Imbalanced throttle valve synchronization
12. Sucking air from throttle valve or vacuum hose
13. Too much engine oil
14. Defective fuel pump or ECM
15. Defective CKP sensor and ignition coils
Defective control circuit or sensor
1. Low fuel pressure
2. Defective TP sensor
3. Defective IAT sensor
4. Defective CKP sensor
5. Defective GP switch
6. Defective IAP sensor
7. Defective ECM
8. TP sensor out of adjustment
9. Defective ISC valve
10. Imbalanced throttle valve synchronization
Adjust.
Replace.
Adjust.
Replace.
Repair.
Clean or replace.
Replace.
Replace.
Adjust.
Clean or replace.
Adjust.
Repair or replace.
Drain out excess oil.
Replace.
Replace.
Repair or replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Adjust.
Replace.
Adjust.
Engine overheats
Defective engine internal parts
1. Heavy carbon deposit on piston crowns
2. Not enough oil in the engine
3. Defective oil pump or clogged oil circuit
4. Sucking air from intake pipes
5. Use incorrect engine oil
6. Defective cooling system
Lean fuel/air mixture
1. Short-circuited IAP sensor/lead wire
2. Short-circuited IAT sensor/lead wire
3. Sucking air from intake pipe joint
4. Defective fuel injectors
5. Defective ECT sensor
Other factors
1. Ignition timing is too advanced due to defective
timing advance system (ECT sensor, GP switch,
CKP sensor and ECM)
2. Drive chain is too tight
3. ISC bad learning
Clean.
Add oil.
Replace or clean.
Repair or replace.
Change.
See radiator section.
Repair or replace.
Repair or replace.
Repair or replace.
Replace.
Replace.
Replace.
Adjust.
Reset learned value.
