Fuel Tank, Function

Fuel Tank, Function




86 Union nut
87 Compression spring
88 Fuel delivery module
89/1 Left closing plate
Pin 1 Fuel pump ground
Pin 2 Fuel gage sensor
Pin 3 Fuel gage sensor
Pin 4 Fuel pump circuit 87
89/2 Right closing plate
90 Fuel pressure line (to connection A)
91 Fuel line (from the suction jet pump to the fuel delivery module)
95 Suction spray pump
B4/1 Fuel level sensor, left half of tank
B4/2 Fuel level sensor, right half of tank
B4/3 Fuel tank pressure sensor (USA)
M3 Fuel pump (FP)
A Connection to fuel filter with integrated fuel pressure regulator
B Return flow connection from fuel pressure regulator
C Fuel induction from left fuel tank chamber to fuel delivery module

The fuel delivery module (88) with the fuel pump (M3) and the "fuel level sensor, right half of tank" (B4/2), is mounted in the right fuel tank chamber. A closing plate (89/1) with connecting pipe, cable connector, suction jet pump (95), fuel level sensor, left half of tank (B4/1) and the fuel tank pressure sensor (B4/3 (USA)) is mounted in the left fuel tank chamber.

The fuel flows from the 2-stage fuel pump in the fuel delivery module along the fuel pressure line (90) via the connection (A) to the fuel filter with integrated fuel pressure regulator. Excess fuel flows back via the return flow connection (B) through the suction jet pump (95) and the fuel line (91) into the right fuel tank chamber. A suction effect is produced in the suction jet pump which draws the fuel from the deepest point out of the left fuel tank chamber and delivers it into the fuel delivery module. This ensures that the left fuel tank chamber is properly emptied.

The housing of the fuel delivery module serves as a swirl pot. When cornering with a low level of fuel in the fuel tank, it prevents the fuel pump drawing in air.

Fuel strainers are provided at the bottom of the fuel delivery module and at the inlet to the fuel pump.

Each fuel tank chamber has a fuel gage sensor (lever sensor with potentiometer and sliding contact). Electrically, the resistances of the two fuel gage sensors are connected in series (each 100 ).
Fuel tank full: approx. 0 ohms
Fuel tank empty: approx. 200 ohms

Note: The fuel tank has no outlet valves. It is drained through the fuel pump via the fuel line in the engine compartment.