Suzuki SFV650, Service Manual

Page: 72 / 573

1A-9 Engine General Information and Diagnosis:
Diagnostic Information and Procedures
Engine Symptom Diagnosis
B944H11104001
Condition Possible cause Correction / Reference Item
Engine will not start or is
hard to start
(Compression too low) Valve clearance out of adjustment. Adjust.
Worn valve guide or poor seating of
valve. Repair or replace.
Mistimed valve. Adjust.
Excessively worn piston rings. Replace.
Worn-down cylinder bores. Replace.
Too slow starter motor cranking. Refer to “Starting System Diagram in Section
1I (Page 1I-1)”.
Poor seating of spark plugs. Retighten.
Defective cylinder head gasket. Replace.
Engine will not start or is
hard to start (Plug not
sparking) Fouled spark plugs. Clean.
Wet spark plugs. Clean and dry.
Defective ignition coil. Replace.
Defective CKP sensor. Replace.
Defective ECM. Replace.
Open-circuited wiring connection. Repair or replace.
Open or short in high-tension cords. Replace.
Engine will not start or is
hard to start (No fuel
reaching the intake
manifold) Clogged fuel filter or fuel hose. Clean or replace.
Defective fuel pump. Replace.
Defective fuel pressure regulator. Replace.
Defective fuel injectors. Replace.
Defective fuel pump relay. Replace.
Defective ECM. Replace.
Open-circuited wiring connection. Check and repair.
Engine will not start or is
hard to start (Incorrect
fuel/air mixture) TP sensor out of adjustment. Adjust.
Defective fuel pump. Replace.
Defective fuel pressure regulator. Replace.
Defective TP sensor. Replace.
Defective CKP sensor. Replace.
Defective IAP sensors. Replace.
Defective ECM. Replace.
Defective ECT sensor. Replace.
Defective IAT sensor. Replace.
Clogged ISC valve air passage way. Repair or replace.
Engine idles poorly Valve clearance out of adjustment. Adjust.
Poor seating of valves. Replace or repair.
Defective valve guides. Replace.
Worn down camshafts. Replace.
Too wide spark plug gaps. Adjust or replace.
Defective ignition coil. Replace.
Defective CKP sensor. Replace.
Defective ECM. Replace.
Defective TP sensor. Replace.
Defective fuel pump. Replace.
Imbalanced throttle valve. Adjust.
Damaged or cranked vacuum hose. Replace.
Damaged or clogged ISC valve. Repair or replace.
ISC incorrect leaning. Reset learned value.
Dirty throttle body. Clean.
Sucking air from throttle valve or intake
pipe. Retighten or replace.