Where is a fuel injector located?

Fuel injectors are located in the fuel delivery system of an internal combustion engine. More specifically, they're positioned between the fuel rail (which supplies fuel under pressure) and the intake manifold or directly into the combustion chamber (in direct injection systems). Therefore, the precise location varies slightly depending on the engine type (e.g., gasoline, diesel) and fuel injection system (e.g., port injection, direct injection).