Fuel Pump Module
| ITEM | DESCRIPTION |
|---|---|
| 1 | Venturi pump |
| 2 | Fuel pump module tank flange |
| 3 | Suction port filter |
| 4 | Left side fuel level sensor float |
| 5 | Fuel cut-off elbow |
| 6 | Suction port pipe |
| 7 | Swirl pot |
| 8 | Fuel pump coarse filter |
| 9 | Right side fuel level sensor float |
Low Pressure Fuel Pump
The Low Pressure (LP) fuel pump is controlled by the Fuel Pump Driver Module (FPDM) via the fuel pump relay located in the Rear Junction Box (RJB). Operation of the fuel pump relay is controlled by the Body Control Module/Gateway Module (BCM/GWM) using signals from the Powertrain Control Module (PCM). The PCM sends data to the FPDM via Pulse Width Modulation (PWM) signals to control LP fuel pump output.
The LP pump collects fuel from the swirl pot and passes it from the tank to the fuel delivery line via the intank fuel filter, to the engine mounted, HP (high pressure) pumps. The fuel is delivered at a pressure of 5.5 to 7.3 bar (79.9 to 105.9 Ibf/in.2) absolute.
Should the fuel pump electrical connection need to be disconnected, it is important that the ignition is switched off (power mode 0 or 4). If the ignition is on (power mode 6), the instrument cluster will store its last fuel gauge needle position prior to power down. Once power is restored the gauge will display the last stored position regardless of the actual level in the tank.
This could result in incorrect fuel gauge readings if the fuel tank has been drained and not filled with exactly the same quantity of fuel that was removed.
Jet Pump
Fuel is collected from the left side of the tank and transferred to the right side of the tank by a single suction tube. The fuel is transferred using a venturi pump. The venturi effect is created by the fuel feed flow from the fuel pump.
Fuel Limit Vent Valve
The Fuel Limit Vent Valve (FLVV) controls the fuel fill volume into the tank. During the refuelling process, air/fuel vapor is displaced (by the fuel entering the tank) and exits the tank via the Fill Limit Vent Valve (FLVV). The air/fuel vapor is conveyed by the fuel tank refuelling breather pipe to exit the system either by the filler head for the EURO or ROW vehicles and via the charcoal canister for NAS vehicles. During filling, as the tank reaches its full level, the float in the FLVV is closed by the rising fuel and prevents air/fuel vapor passing through to the refuelling breather pipe. The resulting back pressure causes refuelling to stop automatically.
Roll Over Valve
The Roll Over Valve (ROV) allows vapor to escape to prevent tank pressurization in normal vehicle operating modes. However this valve is designed to close to prevent fuel leakage through the vent in the event of a vehicle roll over.
Pressure Relief Valve
The Pressure Relief Valve (PRV) is installed in the pipe between the LP fuel pump and the fuel pump module flange to protect the system from excess pressure. The pressure relief valve releases fuel back into the tank if pressure in the pipe increases from 7.3 to 8.3 bar (105.9 to 120.4 lbf/in.2 ) gauge.
Fuel Level Sensors
There are two fuel level sensors located inside the fuel tank. One sensor is attached to the swirl pot and monitors fuel level on the right side of the tank. The second is attached on the suction pipe carrier and monitors fuel level on the left side of the tank.
Both level sensors are Magnetic Passive Position Sensors (MAPPS) which provide a variable resistance to ground for the output from the fuel gauge.