Suzuki Boulevard M50, Service Manual, Page: 396 / 454

10-8 SERVICING INFORMATION
Complaint Symptom and possible causes Remedy
Engine runs poorly
in high speed range. Defective engine internal/electrical parts
1. Weakened valve springs
2. Worn camshafts
3. Valve timing out of adjustment
4. Too narrow spark plug gaps
5. Ignition not advanced sufficiently due to poorly
working timing advance circuit
6. Defective ignition coils
7. Defective CKP sensor
8. Defective ECM
9. Clogged air cleaner element
10. Clogged fuel hose, resulting in inadequate fuel
supply to injector
11. Defective fuel pump
12. Defective TP sensor
13. Defective STP sensor or STV actuator
Defective air flow system
1. Clogged air cleaner element
2. Defective throttle valve
3. Defective secondary throttle valve
4. Sucking air from throttle body joint
5. Defective ECM
6. Imbalancing throttle valve synchronization
Defective control circuit or sensor
1. Low fuel pressure
2. Defective TP sensor
3. Defective IAT sensor
4. Defective CKP sensor
5. Defective GP sensor
6. Defective IAP sensor
7. Defective ECM
8. Out of adjustment TP sensor
9. Defective STP sensor and/or STV actuator
Replace.
Replace.
Adjust.
Adjust.
Replace ECM.
Replace.
Replace.
Replace.
Clean.
Clean and prime.
Replace.
Replace.
Replace.
Clean or replace.
Adjust or replace.
Adjust or replace.
Repair or replace.
Replace.
Adjust.
Repair or replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
SA
MP
LE