Fuel Tank Unit: Description and Operation

Modular Fuel Sender:

Fuel Sender Fuel Flow:

DESCRIPTION
The modular fuel sender assembly mounts to the top of the fuel tank and is spring loaded to the bottom of the fuel tank. It is designed to:

- Provide maximum fuel level in the fuel sender assembly under all driving conditions and fuel tank levels.
- Improve the measuring of the fuel quantity.
- Include a check valve to inhibit the back flow of fuel from the fuel system.

The following components are serviceable:

- Modular fuel sender assembly.
- Fuel level sensor.
- External fuel strainer.

Fuel Pump
The fuel pump is an electric twin turbine high pressure pump mounted inside the modular fuel sender assembly. The fuel is pumped to the engine at a specified flow and pressure by the fuel pump. Excess fuel is returned to the fuel sender by a return pipe. The fuel pump delivers a constant flow of fuel to the engine even during low fuel conditions and aggressive vehicle maneuvers.

The fuel pump operation is controlled by the Powertrain Control Module (PCM) through a fuel pump relay. Refer to Computers and Control Systems / System Diagnosis. this manual for further description and a wiring diagram of the fuel pump relay.

Fuel Pump Strainer
A woven plastic fuel pump strainer is attached the bottom of the fuel sender assembly. The functions of the fuel strainer are to filter contaminants and to wick fuel.

The life of the fuel pump strainer is generally considered to be that of the fuel pump. The fuel pump strainer is self cleaning and normally requires no maintenance. Fuel stoppage at this point indicates that the fuel tank contains an abnormal amount of sediment or water. In which case the fuel tank should be thoroughly cleaned. If the fuel pump strainer is plugged, replace it with a new one.

Fuel Level Sensor
The fuel level sensor is attached to the side of the modular fuel sender assembly. Fuel is sensed by the position of the float and float arm, and a signal is sent to the display in the vehicle instrument cluster.