Start by removing the fuel real test port cap and the small ball (inside the cap). Attach the fuel pressure tester to the test port.
Test for leaks, first by placing a rag under the fittings. Please be safe! If the fitting is not sealed, the leak will not just be a small dribble of fuel but a spray of fine mist. By itself this is not terribly dangerous but if the engine were running the leak will almost certainly result in a fire. To safely pressurize the system and ensure there are no leaks, jumper the DME relay (pins 37 & 87b) as shown above. This will enable the fuel pump and you can then verify or correct leaks.
| Model | Pressure | Delivery Rate | Leak Down |
| 944 NA, 924S | 2.5 +/- 0.2 bar (bridged DME relay) 2.0 bar (engine at idle) |
Min. 850 cm3/30 sec Min. 750 cm3/30 sec (Bosch speed reduced pump with green paint color code # 0.580.464.028) |
Minimum pressure after pump off for 20 minutes = 1 bar |
| 944 S | |||
| 944 Turbo | 2.3 to 2.7 bar (bridged DME relay) 2.0 bar (engine at idle) |
Min. 850 cubic CCs in 30 seconds | Minimum pressure after pump off for 20 minutes = 1 bar |
Torque setting for re-installation of the test port cap = 16 ft/lbs