The reason a vehicle needs a fuel pump is because the fuel tank is located on the opposite side of the vehicle to where the engine is. The job of the fuel pump is to draw the gas towards the engine.
There are two kinds of fuel pumps:
The mechanical fuel pump – this is used in carbureted cars.
The electrical fuel pump – this is used in cars with electronic fuel injection.
A carburetor is a fuel delivery mechanism that uses a form of a vacuum in which to deliver the fuel to the engine. Here, the same vacuum that draws the air-fuel mixture into the engine will also draw the fuel along the lines towards the engine. But, it needs extra help, so carbureted engines have a mechanical fuel pump. This pump runs off the engine’s rotation and you will find it located alongside the vehicle’s engine.
Electronic fuel injection is a fuel delivery system that squirts fuel into the combustion chambers of the engine. A computer controls this system and it monitors the position of the throttle, the air-fuel ratio and the contents of the exhaust. The fuel pump here is located on the inside or next to the fuel tank. The reason for this is because it doesn’t use a force like a vacuum to draw the fuel along the lines. The fuel pump is powered and controlled electronically. You may sometimes be able to identify the fuel pump by hearing a soft humming noise coming from the rear of the car.
The fuel pump doesn’t often fail in vehicles with electronic fuel injection. But, when it does fail, the vehicle will just sputter and die. It won’t restart! The vehicle may seem like it is out of gas even if it’s full. You can check the fuel pump failure by checking the fuel delivery end of the system – if the is no fuel going to the engine, it is more than likely that the fuel pump has given up and failed.
To replace an electronic fuel pump is tricky business, so it is best left to the professionals.
The reason for this is because in some cars, the fuel pump can be found in an area that is easy to get to from underneath the vehicle.
But, in other cars there may be an access panel in the interior of the vehicle that you can remove to be able to reach the fuel pump.
There are some cars that will need the fuel tank to be siphoned and may be removed or dropped before you are able to reach the fuel pump. With this there is a lot of labor involved.