An ACDelco Professional, premium aftermarket Fuel Injector is a high quality replacement for many vehicles on the road today. It is an electro-magnetic valve that meters fuel into the engine’s intake manifold or cylinders for combustion. The engine management computer operates the injector by applying an electric current to the injector solenoid winding-this causes the needle valve to open, and allows the pressurized fuel to be atomized into the intake airstream.