Do not confuse the electric fuel pump with the injection pump.
All Mercedes-Benz fuel injected engines are equipped with electric fuel pumps. The electric fuel pump is located underneath the rear floor panel. The fuel return line was also eliminated and a check ball installed in its place.
Two types of fuel pumps have been used. One, the large pump, has been replaced with a new small design which has a bypass system to prevent vapor lock.
REMOVAL & INSTALLATION
Jack the left rear of the car and support it on jackstands. This will provide sufficient working clearance.
Remove and plug the intake, outlet, and bypass lines from the pump.
Disconnect the electric leads.
Unbolt and remove the fuel pump and vibration pads.
Install the fuel pump in the reverse order of removal. Be sure that the electric leads are connected to the proper terminals. The negative wire (brown) is connected to the negative terminal (brown plastic plate) and the positive wire (black/red) is connected to the positive terminal (red plastic plate). If the terminals are reversed, the pump will operate in the reverse direction of normal rotation and will deliver no fuel.