The Electric Fuel Pump is a device that continuously sucks fuel out of the fuel tank and provides a specified pressure and flow of fuel to the fuel system, and is one of the components of the Electronic Fuel Injection (EFI) system. Based on its function, it can be seen that the performance of the Electric Fuel Pump will directly affect the working performance of the engine, also known as the ‘Heart’ of the Fuel supply system of the EFI engine. It’s basic working principle is that the DC motor is electrified to drive the rotor inside the pump housing to rotate at high speed, the lower section of the rotor shaft is combined with the internal hole section of the impeller, so that when the rotor rotates, the impeller is driven by the rotor shaft to rotate in the same direction, and the impeller high-speed rotation process causes vacuum low pressure in the fuel inlet part, and then the filtered fuel is sucked in form the inlet of the pump cover, and the sucked fuel is injected into the pump casing after being pressurized by the fuel pump impeller and then ejected through the outlet providing fuel with a certain pressure for the fuel system.