Fuel Pressure: Inspection

WARNING: Before removing fuel pressure gauge, release fuel pressure.

NOTE: If out of specification, check or replace pressure regulator and pressure regulator vacuum hose.

Release fuel pressure. Refer to RELEASING OF FUEL PRESSURE .
Open fuel flap lid, and remove fuel filler cap.

Fig 1: Removing Fuel Filler Cap
Courtesy of SUBARU OF AMERICA, INC.
Disconnect fuel delivery hoses from fuel filter, and connect fuel pressure gauge.

Fig 2: Disconnecting Fuel Delivery Hoses
Courtesy of SUBARU OF AMERICA, INC.
Connect fuel pump relay connector.

Fig 3: Connecting Fuel Pump Relay Connector
Courtesy of SUBARU OF AMERICA, INC.
Start the engine.
Measure fuel pressure while disconnecting pressure regulator vacuum hose from intake manifold.
Fuel pressure:
1. Standard; 284-314 kPa (2.9-3.2 kg/cm² , 41-46 psi)
Fig 4: Measuring Fuel Pressure (Vacuum Hose Disconnected)
Courtesy of SUBARU OF AMERICA, INC.
After connecting pressure regulator vacuum hose, measure fuel pressure.
Fuel pressure:
1. Standard; 206-235 kPa (2.1-2.4 kg/cm² , 30-34 psi)
Fig 5: Measuring Fuel Pressure (Vacuum Hose Connected)
Courtesy of SUBARU OF AMERICA, INC.

NOTE: The fuel pressure gauge registers 10-20 kPa (0.1-0.2 kg/cm² , 1-3 psi) higher than standard values during high-altitude operations.