Fuel Pressure: Inspection

WARNING: This page is about a different car, the 2004 Subaru Outback, 2004 Subaru Legacy, and 2004 Subaru Baja. However, it is still accessible from the selected car via links, so may be relevant.

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 , OPERATION, Fuel.
Open fuel flap lid, and remove fuel filler cap.
Disconnect fuel delivery hoses from fuel filter, and connect fuel pressure gauge.

Fig 1: Disconnecting Fuel Delivery Hoses From Fuel Filter
Courtesy of SUBARU OF AMERICA, INC.
Connect connector of fuel pump relay.

Fig 2: Connecting Connector Of Fuel Pump Relay
Courtesy of SUBARU OF AMERICA, INC.
Start the engine.
Measure fuel pressure while disconnecting pressure regulator vacuum hose from intake manifold.
1. Fuel pressure:
  1. Standard: 284 -nnn 314 kPa (2.9 - 3.2 kg/cm² , 41 - 46 psi)
Fig 3: Measuring Fuel Pressure While Disconnecting Pressure Regulator Vacuum Hose
Courtesy of SUBARU OF AMERICA, INC.
After connecting pressure regulator vacuum hose, measure fuel pressure.
1. Fuel pressure:
  1. Standard: 206 - 235 kPa (2.1 - 2.4 kg/cm² , 30 - 34 psi)
Fig 4: Measuring Fuel Pressure
Courtesy of SUBARU OF AMERICA, INC.

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