Fuel Pump: Testing and Inspection

Checking fuel pump capacity

WARNING: Removal of the fuel pressure regulator involves partial dismantling of the car's fuel system. The following points must therefore be observed in connection with this work:
- Work only in a well-ventilated area. If approved equipment for the extraction of fuel vapors is available, be sure to use it.
- Wear suitable gloves. Prolonged contact with fuel can cause skin irritation or dermatitis.
- keep a class BE fire extinguisher near at hand. Be mindful of the danger of sparks caused by short circuits and when connecting and disconnecting leads in electrical circuits.
- No smoking anywhere in the vicinity,
- Wear protective goggles.





1 Remove the engine cover.
2 With the engine running, extract fuse No. 19. Switch off the ignition when the engine has stopped. Fit fuse 19.





3 Detach the return line for the fuel rail, using tool No. 83 94 702. Use a pair of flat-nose pliers to remove the quick-release coupling's rubber seal.





4 Connect the adapter with hose, tool No. 83 94 918, to the fuel rail's return connection. Place the other end of the hose in a suitable receptacle.
5 Ignition switch ON. Activate "Fuel pump flow test" with the diagnostic tool.
If run for 30 seconds, the pump should deliver at least 700 ml of fuel to the receptacle.
6 Remove the test equipment.
7 Reconnect the return line to the fuel rail.
8 Clear diagnostic trouble codes
9 Start the engine and check for fuel leakage.

Important
In all work involving disconnection of the fuel line's quick-release couplings, great care should be taken to avoid damaging the sealing surface of the male coupling half. If the male coupling half is extremely dirty it should be cleaned before disconnection. Also clean the sealing surface after disconnection, if necessary. Use a soft cloth. Lubricate the male coupling half before fitting.