Fuel Pressure Test

Start engine. Warm to normal operating temperature. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE . On TBI, remove fuel filter banjo bolt and install adapter bolt and fitting, pressure gauge and hose. See Fig 1 . On SFI, install coupling, pressure gauge and hose to fuel rail. See Fig 2 . On all models, start engine and ensure no leakage exists at pressure gauge connection. Turn engine off.
Turn ign. on to operate fuel pump for 3 sec. Turn ign off. Repeat 3-4 times, check fuel pressure. See FUEL PUMP PERFORMANCE and REGULATED FUEL PRESSURE . Start engine. Measure fuel pressure at idle. Turn ign off.
If pressures are not within specification, check for defective fuel pump, pressure regulator or restriction in fuel system. Repair as required. Remove fuel pressure gauge and start engine to ensure no fuel leakage exists.

Fig 1: Testing Fuel System Pressure (TBI)

Courtesy of SUZUKI OF AMERICA CORP.

Fig 2: Testing Fuel System Pressure (SFI)

Courtesy of SUZUKI OF AMERICA CORP.

FUEL PUMP PERFORMANCE

Application

⁽¹⁾ psi (kg/cm² )

SFI

⁽²⁾ 36-43 (2.5-3.0)

TBI

⁽³⁾ 34-41 (2.4-2.9)

⁽¹⁾	Key on and engine off.

⁽²⁾	Pressure should maintain at least 26 psi (1.8 kg/cm² ) for one minute after fuel pump is turned off.

⁽³⁾	Pressure should maintain at least 25 psi (1.7 kg/cm² ) for one minute after fuel pump is turned off.

REGULATED FUEL PRESSURE

Application

psi (kg/cm² )

SFI

⁽²⁾ 30-37 (2.1-2.6)

TBI

⁽¹⁾⁽³⁾ 34-41 (2.4-2.9)

⁽¹⁾	Key on and engine off.

⁽²⁾	Pressure should maintain at least 26 psi (1.8 kg/cm² ) for one minute after fuel pump is turned off.

⁽³⁾	Pressure should maintain at least 25 psi (1.7 kg/cm² ) for one minute after fuel pump is turned off.