Fuel Temperature Sensor And Fuel Metering Valve

The fuel temperature sensor is located in a threaded port in the High Pressure (HP) fuel pump.

The Powertrain Control Module (PCM) monitors the fuel temperature constantly. If the fuel temperature exceeds 85°C (185°F), the PCM invokes an engine 'derate' strategy. This reduces the amount of fuel delivered to the injectors in order to allow the fuel to cool. When this occurs, the driver may notice a loss of performance.

The wires to the fuel temperature sensor are monitored by the PCM for short and open circuit. The PCM also monitors the 5 V supply. If a failure occurs a fault is recorded in the PCM memory and the PCM uses a default fuel pressure value.

The fuel metering valve is located on the top of the HP fuel pump. The valve is sealed to the HP fuel pump body with an O-ring seal and secured with two screws.

The fuel metering valve is a variable position solenoid-operated valve that is controlled by the PCM with a Pulse Width Modulation (PWM) signal.

The fuel metering valve controls the quantity of fuel delivered to the HP fuel pump from the Low Pressure (LP) fuel pump module in the fuel tank. The valve returns unwanted fuel back to the fuel tank. This avoids unused fuel being pressurized by the HP stage of the pump, only to be returned back to return system by the fuel pressure control valve.

For additional information, refer to: FUEL CHARGING AND CONTROLS