Fuel Level Sensor: Description and Operation
FUEL PUMP MODULEFuel Pump Module:
The fuel pump module is installed in the top of the fuel tank.
- Electric fuel pump
- Fuel pump reservoir
- Inlet strainer
- Fuel pressure regulator
- Fuel gauge sending unit
- Fuel supply line connection
The inlet strainer, fuel pressure regulator and fuel level sensor are the only serviceable items. if the fuel pump or electrical wiring harness requires service, replace the fuel pump module.
The electric fuel pump is located in and is part of the fuel pump module. It is a positive displacement, gerotor type, immersible pump with a permanent magnet electric motor,
The pump draws fuel through a strainer and pushes it through the motor to the outlet. The pump contains one check valve. The check valve, in the pump outlet, maintains pump pressure during engine off conditions The fuel pump relay provides voltage to the fuel pump..
The fuel pump has a maximum deadheaded pressure output of approximately 635 kPa (95 psi). The regulator adjusts fuel system pressure to approximately 338 kPa (49 psi).
Fuel Pump Electrical Control
Voltage to operate the electric pump is supplied through the fuel pump relay. For an electrical operational description of the fuel pump refer to fuel Pump Relay-PCM Output.
Electrical Pump Replacement
The electric fuel pump is not serviceable. If the fuel pump or electrical wiring harness needs replacement, the complete fuel pump module must be replaced. Perform the Fuel System Pressure Release procedure before servicing the fuel pump.
FUEL LEVEL SENSOR
The level sensor is attached to the side of the fuel pump module. The level sensor consists of a float, an arm, and a variable resistor.
As the fuel level increases, the float and arm move up. This decreases the sending unit resistance, causing the fuel gauge on the instrument panel to read full.
FUEL LEVEL SENSOR-PCM INPUT
The fuel level sensor (fuel gauge sending unit) sends a signal to the PCM to indicate fuel level. The purpose of this feature is to prevent a false setting of misfire and fuel system monitor trouble codes if the fuel level is less than approximately 15 percent of its rated capacity. It is also used to send a signal for fuel gauge operation via the PCI bus circuits.