1994-2000 Passat & 1996-2000 Audi A4 1.8L, 2.0L, 2.8L (V6 & VR6)
- Remove the negative battery cable.
- Remove the vacuum hose from the regulator.
- Remove the retaining clip from the fuel pressure regulator.
- Cover the fuel pressure regulator with a shop towel and remove it from the fuel rail.
- Installation is the reverse of removal.
The fuel pressure regulator controls the fuel pressure in relation to the intake manifold pressure.
- Obtain the following special tools and equipment. Equivalent tools may be substituted for OEM tools listed:
- Pressure tester VAG1318
- Adapter 1318/7
- Adapter 1318/10
- Connector 1318/13
- Verify that the fuel pump is operational and delivery rate is OK.
The pressure tester must be installed with the shut off valve between the fuel supply line and the gauge for proper evaluation of residual pressure tests.
- Disconnect the fuel supply hose from the fuel rail.
- Connect the pressure tester, using required adapters.
- Open the shut-off valve on the pressure tester.
- Start the engine and allow it to idle.
- Measure the fuel pressure: it should be 51 psi (3.5 bar)
- If the proper specification is attained, disconnect the vacuum hose from the fuel pressure regulator. The fuel pressure should increase to 58.8 psi (4.0 bar).
- Switch the ignition to OFF.
- Check for leaks and residual pressure by observing the pressure drop on gauge.
After 10 minutes, the must be a residual pressure of at least 29.4 psi (2.0 bar).
- If residual pressure drops below 29.4 psi (2.0 bar), start the engine and let it idle.
- Turn the ignition switch to OFF after pressure has built up.
- Close the shut off valve on the pressure tester.
- Observe the pressure drop.
- If the pressure does not drop, check the check valve in the fuel pump.
- If the pressure drops again, open the shut-off valve on the pressure tester.
- Start the engine and run at idle.
- Turn the ignition switch to OFF after pressure build-up.
- At the same time pinch off the fuel return hose from the regulator to the fuel tank.
- If the pressure does not drop, replace the pressure regulator.
- If the pressure drops again, check pipe connections, O-rings on fuel rail and fuel injectors for leaks.