Fuel Delivery and Air Induction: Description and Operation

GF07.61-P-3004G ME-SFI Fuel Supply, Function
- ENGINE 273 in MODEL 463.202 /222 /236 /237 as of model year 2009 / AEJ 08





Without code (ZU8) USA version
1 Filler neck
2 Valve
3 Fuel tank filter
17 Fuel rail
40 Fuel pressure damper
55 Fuel filter
75 Fuel tank
77 Activated charcoal canister
B4 Fuel level sensor
M3 Fuel pump
Y62 Fuel injection valves
Y58/1 Purge control valve
A Fuel feed (pressure)
B Fuel return (unpressurized)
C Purge control
D Bleeding





For code (ZU8) USA version
1 Filler neck
2 Container
3 Fuel tank filter
17 Fuel rail
40 Fuel pressure damper
55 Fuel filter
75 Fuel tank
77 Activated charcoal canister
B4 Fuel level sensor
B4/3 Fuel tank pressure sensor
M3 Fuel pump
Y62 Fuel injection valves
Y58/1 Purge control valve
Y58/4 Activated charcoal filter shutoff valve
A Fuel feed (pressure)
B Fuel return (unpressurized)
C Purge control
D Bleeding

Function requirements for fuel supply for the ME gasoline injection and ignition system (motor electronics) (ME), general points
- Circuit 15 ON (ignition ON)
- Circuit 87M ON (engine control ON)

ME fuel supply, general points
In all operating conditions, the fuel supply delivers filtered fuel to the injection valves from the fuel tank, in sufficient quantity and at sufficient pressure (injection pressure).

ME fuel supply, function sequence
The fuel supply function sequence is subdivided into the following points:
- Fuel pump control function sequence
- Fuel delivery function sequence

Fuel pump control function sequence
The fuel pump is actuated directly by the ME-SFI [ME] control unit (N3/10) via the fuel pump relay (N10/2kA).
The voltage supply for the fuel pump is performed via the fuel pump relay.

Fuel delivery function sequence
The fuel pump suctions the fuel out of the fuel feed module and pumps it through the fuel filter to the fuel manifold (single line system). In doing so, the fuel pressure is limited by the pressure limiting valve to about p = 3.8 bar.
There is a check valve at the feed point of the fuel filter which prevents reduction of the fuel pressure when the fuel pump is switched off.
The fuel return from the pressure limiting valve supplies fuel to the suction jet pump in the LH fuel tank chamber. The suction jet pump delivers fuel from the LH fuel tank chamber into the fuel feed module (RH fuel tank chamber).