Fuel Pump Module
| ITEM | DESCRIPTION |
|---|---|
| 1 | Fuel return connection |
| 2 | Fuel supply connection |
| 3 | Fuel level sensor electrical connector |
| 4 | Fuel pump electrical connector |
| 5 | Fuel Fired Booster Heater (FFBH) supply connection |
| 6 | Fuel inlet filter |
| 7 | Fuel Fired Booster Heater (FFBH) suction tube and seal (if fitted) |
| 8 | Fuel level sensor float |
| 9 | Swirl pot |
| 10 | Active fuel level sensor - 'A' |
| 11 | Jet pump connection - left (passive) side of fuel tank |
| 12 | Locking ring and O-ring seal |
The Low Pressure (LP) fuel pump module is controlled by the Powertrain Control Module (PCM) via the fuel pump relay. The fuel pump relay is located in the Rear Junction Box (RJB).
The LP fuel pump module is located in the right side of the tank. The fuel pump module flange is sealed to the tank with an O-ring and secured with a locking ring.
The top flange of the fuel pump module assembly provides the internal and external interface for the tank electrical and fuel connections. The flange is formed with fuel level and fuel pump external electrical connectors that are connected to the active and passive fuel level sensors, and the in-tank fuel pump.
The lower part of the LP fuel pump module forms the fuel swirl pot. The swirl pot provides a constant reservoir of fuel for the engine demands.
The High Pressure (HP) fuel pump draws fuel during periods of high demand. At all other times the LP fuel pump supplies the required fuel at a positive pressure.
The fuel is transferred using a venturi pump. The venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section of a pipe. The venturi effect is created by the fuel feed flow from the fuel pump. The rapid flow of fuel through the suction pipe creates a depression. The depression draws the fuel back from the left (passive) side of the fuel tank into the fuel pump (active) side of the fuel tank.
The second venturi effect draws the fuel from the pump side of the fuel tank into the swirl pot. Surplus fuel entering the fuel swirl pot overflows into the usable right side of the fuel tank. The LP fuel pump provides sufficient fuel in the swirl pot to feed the HP fuel pump.
For cold climate market vehicles that feature a Fuel Fired Booster Heater (FFBH) and an auxiliary fuel pump, the fuel pump module has a separate pipe connection for a fuel supply line that connects to an auxiliary fuel pump mounted on the exterior right side of the fuel tank. This pipe connection is fitted with a sealed suction tube which draws fuel from the swirl pot. An additional fuel line connects the auxiliary fuel pump to the FFBH fuel inlet.