Suzuki Intruder VZR1800 Service Manual page 480

11-10 SERVICING INFORMATION
Complaint
Engine runs poorly
in high speed range.
Symptom and possible causes
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 ignition coil/plug caps
8. Defective CKP sensor
9. Defective ECM
10. Clogged air cleaner element
11. Clogged fuel hose, resulting in inadequate fuel
supply to injector
12. Defective fuel pump
13. Defective TP sensor
14. Defective STP sensor or STVA
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 CMP sensor
5. Defective CKP sensor
6. Defective GP sensor
7. Defective IAP sensor
8. Defective ECM
9. TP sensor out of adjustment
10. Defective STP sensor and/or STVA
11. Defective ISC valve
Remedy
Replace.
Replace.
Adjust.
Adjust.
Replace ECM.
Replace.
Replace.
Replace.
Replace.
Clean.
Clean and prime.
Replace.
Replace.
Replace.
Replace.
Adjust or replace.
Adjust or replace.
Repair or replace.
Replace.
Adjust.
Repair or replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.