Sprinter 2500 L5-2.7L DSL Turbo (2003)
Fuel Pressure Sensor: Description and Operation
Fuel Pressure Sensor
The fuel pressure sensor provides the current low pressure (the pressure that exist at the inlet of the high pressure injection pump) fuel pressure to the
ECM.
The fuel pressure when the engine is idling is approximately 36 psi (2.5 Bar). The fuel pressure while driving is 50-58 psi (3.5 - 4.0 Bar).
The fuel rail pressure sensor provides the current fuel rail pressure to the ECM.
A diaphragm and an electric resistance meter are integrated in the fuel pressure sensor. The non-constant fuel system pressure from the low pressure fuel
pump influences the position of the diaphragm which in turn alters it's electrical resistance. This resistance is analyzed by the ECM. The ECM then
actuates the fuel rail pressure control valve until the desired rail pressure value is obtained.
The fuel rail pressure sensor measures the current fuel rail pressure and sends a voltage signal to the ECM. The ECM then actuates the fuel rail pressure
control valve solenoid until the desired rail pressure is achieved.
