The core function of the fuel pump Suction of fuel: Overcoming gravity, continuously drawing out the fuel from the bottom of the fuel tank. Establishing pressure: Provide the fuel system with sufficient pressure to ensure that the fuel can overcome the resistance of the pipeline and be precisely injected into the engine cylinder. Steady fuel supply: Regardless of the engine's operating condition (start-up, idle, acceleration, etc.), it can provide a continuous and stable fuel flow. Type of Major 1.Built-in fuel pump (inside the fuel tank) 2.External fuel pump (outside the fuel tank) .