Milan FWD L4-2.3L (2008)
Fuel Temperature Sensor: Description and Operation
FUEL RAIL PRESSURE TEMPERATURE (FRPT) SENSOR
Typical Fuel Rail Pressure Temperature (FRPT) Sensor
The FRPT sensor measures the pressure and temperature of the fuel in the fuel rail and sends these signals to the PCM. The sensor uses the intake
manifold vacuum as a reference to determine the pressure difference between the fuel rail and the intake manifold. The relationship between fuel
pressure and fuel temperature is used to determine the possible presence of fuel vapor in the fuel rail.
The temperature sensing portion of the FRPT sensor is a thermistor device in which resistance changes with temperature. The electrical resistance of the
thermistor decreases as the temperature increases, and the resistance increases as the temperature decreases. The varying resistance changes the voltage
drop across the sensor terminals and provides electrical signals to the PCM corresponding to temperature.
Both the pressure and temperature signals are used to control the speed of the fuel pump. The speed of the fuel pump sustains fuel rail pressure which
preserves fuel in its liquid state. The dynamic range of the fuel injectors increase because of the higher rail pressure, which allows the injector pulse
width to decrease.
