Fuel pump check valve, checking: Checking

• Disconnect fuel supply line at fuel rail.
  Fig 1: Disconnecting Fuel Supply Line At Fuel Rail

  
• Install pressure gauge VAG 1318 with adapter between fuel supply line and fuel rail.
  Fig 2: Installing Pressure Gauge VAG 1318 With Adapter Between Fuel Supply Line And Fuel Rail

  
• Connect remote control VAG 1348/3A. See FUEL PUMP, CHECKING  .
• Press and hold remote control switch for approx. 30 seconds.
• Close valve on pressure gauge.
• Observe drop in pressure for 10 minutes.

  Maximum pressure drop (after 10 minutes): 0.5 bar (7 psi)

If pressure drop is not OK:

• Check pressure gauge connectors for leaks.
• Check fuel lines for leaks.

If there are no leaks:

• Replace fuel pump and integrated reservoir. See FUEL PUMP WITH INTEGRATED RESERVOIR, REMOVING AND INSTALLING  .