Power supply system — general information (BMW 5 Series E39)

The fuel system includes a fuel back, a fuel pump located in the fuel tank, fuel lines, and fuel and air filters. The injection systems of gasoline and diesel engines are discussed in the following sections.

The plastic fuel tank with a capacity of 70 liters is secured with clamps and is located under the rear seat in front of the rear axle. The tank is divided into 2 chambers. The fuel tank is ventilated by a system that includes an activated carbon filter. The activated carbon filter is installed behind the rear left wheel arch trim. The driver monitors the available fuel supply using the fuel gauge. The fuel level is measured separately for each chamber using a lever sensor. The microprocessor located in the instrument panel calculates the instantaneous fuel supply in the tank based on injection pulses, vehicle speed and the electrical signal from the lever sensor.