Low Pressure Fuel System - E70: Notes

The low pressure fuel system on the E70 is a "pressure regulated" system which uses the signal from the fuel pressure sensor located in the low pressure fuel line.

The fuel pump operates with "ignition ON". If the engine is not started, the fuel is switched off at a specific pressure. When the engine is running, the fuel pump is regulated on-demand by the EKP module in response to a load signal from the DDE in order to ensure a uniform fuel pressure at the inlet to the high-pressure pump.

The functions of the low pressure fuel system are integrated into the DDE control module. The DDE uses the pressure information from the combined fuel pressure-temperature sensor to determine the current actual pressure in the low pressure system.

In order to maintain the approximate delivery pressure of 4.8 to 5.0 bar, the DDE uses a number of input variables. The input variables relevant to determining the adjusting value are:

• Actual pressure in the pre-supply system
• Engine speed
• Injection volume

The adjusting value is sent from the DDE to the EKP module in the form of a CAN message.