Carter Fuel Injector is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector.All diesel engines use fuel injection by design. Petrol engines can use gasoline direct injection, where the fuel is directly delivered into the combustion chamber, or indirect injection where the fuel is mixed with air before the intake stroke.Fuel rail connected to the injectors that are mounted just above the intake manifold on a four-cylinder engine.On petrol engines, fuel injection replaced carburetors from the 1980s onward. The primary difference between carburetion and fuel injection is that fuel injection atomizes the fuel through a small nozzle under high pressure, while a carburetor relies on suction created by intake air accelerated through a Venturi tube to draw the fuel into the airstream.