Suzuki GSF1250 Service Manual

Fuel System: 1G-4
Diagnostic Information and Procedures
Fuel System Diagnosis
B718H11704001
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 GSF1250 Specifications

General

Displacement	1255 cc
Bore x Stroke	79.0 mm x 64.0 mm
Compression Ratio	10.5:1
Fuel System	Fuel injection
Transmission	6-speed, constant mesh
Front Suspension	Telescopic, coil spring, oil damped
Rear Suspension	Link type, coil spring, oil damped
Front Brakes	Dual hydraulic disc
Rear Brakes	Single hydraulic disc
Front Tire	120/70ZR17M/C (58W), tubeless
Rear Tire	180/55ZR17M/C (73W), tubeless
Overall Length	2130 mm
Overall Width	790 mm
Seat Height	805 mm
Wheelbase	1485 mm
Fuel Tank Capacity	19.0 L
Starter	Electric
Final Drive	Chain
Ignition	Electronic ignition (transistorized)
Engine Type	4-stroke, liquid-cooled, DOHC
Ground Clearance	135 mm