A fuel pump helps move fuel through a vehicle's engine. The fuel pump functions like the heart of the engine, pumping the fuel through the components to keep it running. Most pumps are electric in newer cars and keep a specific pressure on the fuel as it flows to the carburetor or the fuel injectors.
The fuel pump is typically found in the fuel tank, where it is kept cool and away from vapors in the engine that could harm it. The pressure created in the pump is referred to as positive pressure because it pushes the fuel forward instead of using pressure to pull the fuel out of the engine. The fuel pump relay powers the fuel pump. The relay itself is turned on and works when the ignition is turned over. Most pumps are also paired with a type of filter. The filter works to keep any kind of contaminants that might be inside the fuel out of the engine. If these were able to get into the fuel system, this could cause hesitation and backfires because the injectors or carburetors can become clogged. Clogged fuel injectors and carburetors can result in serious engine damage or could cause the engine to stop running altogether without any sort of warning.