Primary Fuel Tank Fuel Pump Module

An electric turbine style fuel pump attaches to the primary fuel tank fuel pump module inside the fuel tank. The fuel pump supplies fuel through the fuel feed pipe to the high pressure fuel pump. The fuel tank fuel pump module contains a reverse flow check valve. The check valve maintains fuel pressure in the fuel feed pipe in order to prevent long cranking times. The primary fuel tank fuel pump module is located inside of the left side of the fuel tank. The primary fuel tank fuel pump module consists of the following major components:

• The fuel level sensor
• Front Wheel Drive Models only, the fuel limit vent valve
• The fuel pump and reservoir assembly
• The fuel filter
• The pressure relief regulator valve
• The fuel strainer
• The primary jet pump
• The secondary jet pump

Fuel Level Sensor 

The fuel level sensor consists of a float, a wire float arm, and a ceramic resistor card. The position of the float arm indicates the fuel level. The fuel level sensor contains a variable resistor which changes resistance in correspondence with the position of the float arm. The Engine Control Module (ECM) sends the fuel level information via the serial data circuit to the Instrument Panel Cluster (IPC) in order to control the fuel gauge. The control module monitors the signal circuits of the primary fuel level sensor and the secondary fuel level sensor in order to determine the fuel level.

Fuel Pump and Reservoir Assembly 

The fuel pump is mounted in the fuel tank fuel pump module reservoir. The fuel pump is an electric pump. Fuel is pumped to the high pressure fuel pump at a pressure that is based on feedback from the fuel pressure sensor. The fuel pump delivers a constant flow of fuel even during low fuel conditions and aggressive vehicle maneuvers. The fuel pump flex pipe acts to dampen the fuel pulses and noise generated by the fuel pump.

Fuel Filter 

The fuel filter is located in the primary fuel tank fuel pump module. The paper filter element traps particles in the fuel that may damage the fuel injection system.

Pressure Relief Regulator Valve 

The pressure relief regulator valve replaces the typical fuel pressure regulator used on a mechanical returnless fuel system. The pressure relief regulator valve is closed during normal vehicle operation. The pressure relief regulator valve is used to vent pressure during hot soaks and also functions as a fuel pressure regulator in the event of the Fuel Pump Driver Control Module defaulting to 100% Pulse-Width Modulation (PWM) of the fuel pump. Due to variation in the fuel system pressures, the opening pressure for the pressure relief regulator valve is set higher than the pressure that is used on a mechanical returnless fuel system pressure regulator.

Primary Jet Pump 

The primary jet pump is located in the primary fuel tank fuel pump module. Fuel pump flow loss, caused by vapor expulsion in the pump inlet chamber, is diverted to the primary jet pump and the secondary jet pump through a restrictive orifice located on the pump cover. The primary jet pump fills the reservoir of the primary fuel tank fuel pump module.

Secondary Jet Pump 

The secondary jet pump creates a venturi action which causes the fuel to be drawn from the secondary side of the fuel tank, through the transfer pipe, to the primary side of the fuel tank.