Fuel Pressure Sensor: Description and Operation

Fuel Rail Pressure (FRP) Sensor:

The fuel pressure sensor senses the pressure difference between the fuel injection supply manifold and the intake manifold, and provides the powertrain control module with the current fuel injection supply manifold pressure. The return fuel line to the fuel tank has been deleted in this type of fuel system. The differential fuel/intake manifold pressure provides an indication of the fuel vapors in the fuel rail.

The powertrain control module uses this information to vary the duty cycle output to the Fuel Pump Driver Module (FPDM) which controls the speed of the fuel pump. The speed of the fuel pump sustains fuel injection supply manifold pressure which preserves fuel in its liquid state.

The dynamic range of the fuel injectors increase is due to the higher
pressure, which allows the injector pulse width to decrease.