Fuel Pressure Regulator: Testing and Inspection

CHECKING FUEL PRESSURE REGULATOR AND RESIDUAL PRESSURE

REQUIREMENTS
^ Fuel Pump delivery quantity OK.

WARNING: To prevent fuel spray and a potential fire hazard when loosening connecting points, place rags around respective connection.




PROCEDURE
- Unscrew cap screw from measuring port and connect VAG 1318 gauge with VAG 1318/10 adapter.

CAUTION: Shut-off lever on tester must be closed. Lever must be at right angle to direction of flow (arrow).

- Start engine and let engine idle.
- Measure fuel pressure.

^ Specified value: approx. 2.5 bar (36 psi).




- Disconnect vacuum hose -1- from connector line -2-.

^ Fuel pressure must increase: approx. 3.0 bar (43 psi).

- Switch ignition OFF.
- Check for leaks and residual pressure by watching for pressure drop on gauge.
- After 10 minutes, at least 2 bar (29 psi) pressure must still remain.

- If it does not:

- Start engine and let idle.
- After pressure builds up, switch ignition off and simultaneously clamp return hose (hose has arrow pointing away from fuel rail).
- Watch whether pressure drops on gauge.

- If it does not:

- Replace Fuel Pressure Regulator.

- If pressure drops again:

- Check Fuel Pump check valve.
- Check fuel lines, O-rings on fuel rail and Fuel Injectors for leaks.

WARNING: Before disconnecting pressure gauge, hold a container near the connection and reduce fuel pressure by opening the valve to help prevent a potential fire hazard.