Diagnosing and Replacing a Fuel Pump
What is a fuel pump and why is it necessary?
Fuel pumps can either be mechanical or electrical. Mechanical fuel pumps are of course cheaper than electric fuel pumps and are quiet, easy to install and don’t require any special wiring like an electric fuel pump would. For many carbureted fuel systems, a mechanical fuel pump will be able to handle an engine under 450HP. However, for higher output engines, either running nitrous or higher horsepower ratings, an electric fuel pump will be needed due to its increased strength and increased flow.
Electric fuel pumps are needed when higher fuel pressures are required, such as a high performance sports car or a drag/track only vehicle. These types of pumps offer a much larger variety of flow rates and pressure outputs as opposed to mechanical style fuel pumps. Most commonly used electric fuel pumps will require a 12 volt circuit with the use of a relay. This gives you multiple shut off options. Most of the commonly seen electric fuel pumps are gravity fed and are designed to push fuel. This means it is important that they are properly mounted below and close to the gas tank of your car.
Sometimes fuel pumps can go bad and this video shows just how you can diagnose and replace your own fuel pump.