Electric fuel pumps generate a pressure that varies from 20 to 70 pounds of pressure. The fuel pressure regulator ensures that the pressure is maintained and returns the excess fuel down the return line. Electrical pump are controlled by the ignition switch which operates the pump relay to turn the pump on. Mechanical pumps generate a fuel pressure that varies from 4 to 8 pounds of pressure. The motion of the camshaft pulls the lever up and down to facilitate the suction and expulsion actions of the pump. Older car models incorporate a mechanical pump that is driven by the camshaft of the engine through a lever that is connected to one of the lobes on the camshaft. The fuel pump, along with its associated components, supplies the engine with the right amount of fuel needed to generate the desired output. Seeing that the fuel pump is especially prone to wear it should always be replaced as and when stipulated in the guidelines set out by your car's manufacturer.The Ford Expedition Fuel Pump Assembly comes with all the components that are essential to keeping your engine supplied with fuel. Should you experience problems with the fuel supply, then it is advisable to have the fuel system and the fuel pump inspected and, if necessary, have the fuel pump replaced. That said, problems with the fuel supply are not necessarily always down to the pump, there can be a variety of issues (like a clogged fuel filter). In other cases a fuel pump can malfunction completely, which means that no fuel is pushed to the engine, as a result the engine will not start or cut out. It usually means that parts of the pump have worn or that its electrical and elements connections let through an irregular current. Similarly, it can be that the car suddenly surges forward when driving at a constant speed. Sometimes it can be that the fuel pump does not pump an adequate amount of fuel to the engine, causing the engine to sputter, with the car slowing down and speeding up constantly. Depending on whether the car has a mechanical or an electronic fuel pump a number of issues can arise. Over time, due to continuous use, the fuel pump can wear and eventually fail leading to an unstable flow of fuel being directed towards the engine.

2005 expedition fuel pump replacemwnt