Suzuki GSF650 Service Manual

1G-4 Fuel System:
Diagnostic Information and Procedures
Fuel System Diagnosis
B817H21704001
Condition Possible cause Correction / Reference Item
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 connections. Check and repair.
Engine will not start or is
hard to start (Incorrect
fuel/air mixture)
Defective fuel pump. Replace.
Defective fuel pressure regulator. Replace.
Defective TP sensor. Replace.
Defective CKP sensor. Replace.
Defective IAP sensor. Replace.
Defective ECM. Replace.
Defective ECT sensor. Replace.
Defective IAT sensors. Replace.
Dirty throttle body. Clean.
Defective ISC valve. Replace.
Engine stalls often
(Incorrect fuel/air mixture)
Defective IAP sensor or circuit. Repair or replace.
Clogged fuel filter. Clean or replace.
Defective fuel pump. Replace.
Defective fuel pressure regulator. Replace.
Damaged or cracked vacuum hose. Replace.
Defective ECT sensor. Replace.
Defective thermostat. Replace.
Defective IAT sensor. Replace.
Defective ISC valve. Replace.
Engine stalls often (Fuel
injector improperly
operating)
Defective fuel injectors. Replace.
No injection signal from ECM. Repair or replace.
Open or short circuited wiring
connection.
Repair or replace.
Defective battery or low battery voltage. Replace or recharge.
Engine runs poorly in
high speed range
(Defective control circuit
or sensor)
Low fuel pressure. Repair or replace.
Defective TP sensor. Replace.
Defective IAT sensor. Replace.
Defective IAP sensor. Replace.
Defective ECM. Replace.
Defective STP sensor or STVA. Replace.
Defective GP switch. Replace.
Defective CKP sensor. Replace.
Engine lacks power
(Defective control circuit
or sensor)
Low fuel pressure. Repair or replace.
Defective TP sensor. Replace.
Defective IAT sensor. Replace.
Defective CKP sensor. Replace.
Defective GP switch. Replace.
Defective IAP sensor. Replace.
Defective ECM. Replace.
Defective STP sensor or STVA. Replace.

Suzuki GSF650 Specifications

General

Displacement	656 cc
Bore x Stroke	65.5 mm x 48.7 mm
Compression Ratio	11.5:1
Fuel System	Fuel injection
Ignition	Electronic ignition (transistorized)
Starter	Electric
Transmission	6-speed, constant mesh
Final Drive	Chain
Front Suspension	Telescopic, coil spring, oil damped
Rear Suspension	Link type, coil spring, oil damped
Front Tire	120/70ZR17M/C (58W), tubeless
Rear Tire	160/60ZR17M/C (69W), tubeless
Overall Length	2, 130 mm
Rear Brakes	Disc brake
Fuel Tank Capacity	19.0 L
Wheelbase	1, 470 mm
Seat Height	790 mm
Ground Clearance	135 mm
Engine Type	4-stroke, liquid-cooled, DOHC, 4-cylinder