Fuel Pressure Check Valve: Testing and Inspection

WORK SEQUENCE

WARNING: Fire hazard. Do not smoke or have anything in area that can ignite fuel

CHECKING CONDITIONS

WARNING: Leave lever of pressure gauge in closed position

- Fuel distributor OK
- cold-start valve OK
- fuel accumulator OK
- fuel pump OK
- injectors OK
- no fuel leaks
- engine oil temperature approximately 50°C (122°F)





- loosen fuel filter (right arrow)
- remove fuel line at fuel filter (left arrow)





- connect pressure gauge VW 1318 or P 378 to fuel filter (arrow) with adapter VW 1318/23





1984-1985





1986-1988
- remove fuel pump relay from fuse/relay panel (see arrow)
- VW 1348/3A switched OFF
- connect VW 1348/3A to fuse/relay panel in place of fuel pump relay
- turn switch of VW 1348/3A ON for 15 seconds then switch OFF
- watch pressure drop on gauge
- should not drop below 2.6 bar (38 psi) after 10 minutes

If pressure NOT OK
- check fuel supply connections

If connections OK
- replace fuel pump check valve