ME-SFI fuel pump actuation, function - GF07.61-P-3012V

ENGINE 273.961 in MODEL 216, 221 up to Model Year 8 

Shown on engine 272 in model 171 

Fig 1: Fuel Pump Actuation Function Diagram

Courtesy of MERCEDES-BENZ USA

The fuel pump is actuated over the fuel pump relay by a ground signal from the ME-SFI [ME] control unit.

If the power contact of the relay is closed, the in-tank fuel pump control unit is connected via "terminal 87" with "terminal 30" (B+). Terminal 30 is protected by a 20 A fuse.

If the fuel pump does not run, first check the voltage supply to the ME-SFI [ME] control unit, then the fuel pump fuse and the fuel pump line terminals.

Fuel pump actuation has the following tasks:

• The fuel pump is actuated for complete filling for "ignition ON" for about 5 seconds. The engine must be started before the fuel pump is actuated again. In order to achieve short starting times, ensuring full fuel flow is required, in particular following long shutoff times.
• In order to start the engine the fuel pump is actuated for a recognized starter recognition (terminal 50 Signal).
• For a running engine the fuel pump is actuated by the recognized engine speed signal.
• In the case of a detected front crash actuation of the fuel pump is interrupted.