Undo covering cap on test connection of fuel collection pipe and remove.
Connect pressure gauge (special tool P 378a) with connecting line (special tool 9559) and connect to test connection.

Fig 1: Connecting Pressure Gauge (Special Tool P 378A) With Connect Line
Courtesy of PORSCHE OF NORTH AMERICA, INC.
Actuating fuel pump with Porsche System Tester 2: The fuel pump can be actuated with the Porsche System Tester 2 or by bridging the fuel-pump relay. Via fuel-pump relay without Tester: Disconnect fuel-pump relay from the central electrical board and bridge contacts 30 and 87 (identified as 3 and 5 on the central electrical board) with a fused shop-made cable. See Fig 2 . The fuel pump must now operate or deliver fuel.

Fig 2: Bridging The Fuel-Pump Relay To Activate Fuel Pump
Courtesy of PORSCHE OF NORTH AMERICA, INC.
Nominal test values:

Stationary engine 3.8 +/- 0.2 bar

Engine idling 3.3 +/- 0.2 bar

NOTE:

The seal or sealing ring in the brass closure cap is not exchangeable. It must therefore be used only once.
Tightening torque of new brass closure cap 2.5 +/- 0.5 Nm (2.0 +/-0.5 ftlb.).

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Checking fuel pressure: Checking