Fuel Pressure

WARNING: Always relieve fuel pressure before disconnecting any fuel injection-related component. DO NOT allow fuel to contact engine or electrical components.

Remove hot-air guide at left rear of engine compartment. Disconnect fuel return line from fuel distributor. See Fig 1 . Connect fuel pressure gauge. Catch any spilled fuel using a shop rag.
Disconnect DME relay from fuse/relay block. Jump terminals No. 30 and 87b together. See Fig 1 . Fuel pump should operate at specified pressure. See FUEL PUMP PERFORMANCE table.

CAUTION: DO NOT pinch polyamide fuel pipes closed for any reason. Polyamide pipes cannot be bent or clamped without causing permanent damage. DO NOT allow sealing ball to fall out when removing cap nut.

FUEL PUMP PERFORMANCE

Application

Pressure psi (kg/cm² )

Volume In 30 Sec. Pts. (L)

911 Carrera 911 Carrera 4

⁽¹⁾ 52-58

1.8

(3.6-4.0)

(.85)

⁽¹⁾	Unregulated pressure (no vacuum applied to pressure regulator). Regulated pressure (vacuum applied to pressure regulator) is 45-51 psi (3.1-3.5 kg/cm² ).

Fig 1: Testing Fuel Pump Pressure & Volume

Courtesy of PORSCHE OF NORTH AMERICA, INC.