HYOSUNG AQUILA 250 FI, Service Manual, Page: 70 / 90

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SERVICING INFORMATION 7-1-4
Complaint Symptom and possible causes Remedy
Engine idles poorly. 1. Tappet clearance out of adjustment.
2. Poor seating of valves.
3. Defective valve guides.
4. Worn down camshafts.
5. Too wide spark plug gaps.
6. Defective ignition coils.
7. Defective pick-up coil.
8. Defective ECU.
9. Defective fuel pump.
10. Imbalanced throttle valve or SAV solenoid.
11. Damaged or cracked vacuum hose.
Incorrect fuel / air mixture
1. Defective IAP sensor or circuit.
2. Clogged fuel filter.
3. Defective fuel pump.
4. Defective fuel pressure regulator.
5. Defective ET sensor.
6. Defective IAT sensor.
7. Damaged or cracked vacuum hose.
Fuel injector improperly operating
1. Defective fuel injectors.
2. No injection signal from ECU.
3. Open or short circuited wiring connection.
4. Defective battery or low battery voltage.
Control circuit or sensor improperly operating
1. Defective ECU.
2. Defective fuel pressure regulator.
3. Defective IAT sensor.
4. Defective pick-up coil.
5. Defective ET sensor.
6. Defective fuel pump relay.
Engine internal parts improperly operating
1. Fouled spark plugs.
2. Defective pick-up coil or ECU.
3. Clogged fuel hose.
4. Tappet clearance out of adjustment.
Adjust.
Replace or repair.
Replace.
Replace.
Adjust or replace.
Replace.
Replace.
Replace.
Replace.
Adjust.
Replace.
Repair or replace.
Clean or replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Repair or replace.
Repair or replace.
Replace or recharge.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Clean.
Replace.
Clean.
Adjust.
Engine stalls often