Test Point 17 - Fuel Pressure

TEST POINT 17: Fuel pressure

The fuel collection pipe has a test connection at the front right. Unscrew the cap nut of the test connection.

CAUTION: The ball seal inside could fall out. Connect a P 378 or VW 1318 pressure gauge to the test connection. Start the engine and run at idle speed with vacuum at the pressure regulator.

Test pressure 3.3 ± 0.2 bar (50 ± 3 psi)

If there are hot starting problems:
- Check with the engine stopped and the fuel pump running, without vacuum at the pressure regulator (to do this, remove the relay and bridge terminals 87 and 30): Test pressure 3.8 ± 0.2 bar (55 ± 3 psi)

- Switch off the fuel pump. Read off the pressure value at the test pressure gauge (nominal value 3.8 ± 0.2 bar (55 ± 3 psi)).

- Maximum permissible pressure drop with engine warm: 0.5 bar (7.25 psi) in 30 minutes.

- If pressure drops below the specified value, proceed as follows:

- Build up pressure again by switching the fuel pump on briefly. Remove the return pipe at the pressure regulator )the fuel pump must not be switched on).