Checking the fuel consumption in the return fuel lines of the injectors at the starter speed
Note: If the engine does not start, you can check the fuel flow in the return lines of the injectors also while turning the starter. For each individual injector, the return flow of fuel is small. If this value is greater for one of the injectors than for the others. then this injector is probably defective.
Remove the top engine cover. Before disconnecting all connectors, clean them (e.g. cleaner «Kaltreiniger»). Dry all cleaned parts. Remove soundproofing. Pull the fuel return connector out of the injector by pulling the catches upwards -arrows-.
Note: Maintain cleanliness. Do not allow dirt to enter the removed fuel return lines and injector connectors.
Disconnect electrical connector -2- from fuel pressure regulator -N276- -pos. 1-.
Note: This prevents fuel injection when trying to start the engine.
Firmly put adapter C6 on the connectors of the fuel return lines of all 4 injectors. Connect hoses of fuel return flow meter -VAS 6684- to adapter. Crank the engine three times with the starter (to avoid overheating the starter, wait approximately 20 seconds between starting attempts). Set return volume: 0 ml. If fuel leaks from an injector, the injector must be replaced. Reconnect electrical connector for fuel pressure regulator -N276-.
Installation of fuel return lines
Press the fuel return fittings until they click into place on the injectors. Then push down the staples on both sides. Check fuel system for leaks. Interrogation and removal of errors from the event recorder of the engine control unit.