Fuel Injector

The fuel injector, an electrical solenoid, is mounted in the throttle body on non-turbo models so that fuel from the injector is directed into the incoming air stream. On turbo models, 4 injectors are mounted on a fuel rail, supplying the intake manifold with the proper fuel supply.

While power to the injector is supplied by the power module, it is controlled by indirect signal from the logic module, which actually determines when and how long the injector is open. When electric current is supplied to the injector, an integral armature and pintle valve move a short distance against a spring, opening a small orifice.

Fuel supplied to the injector is forced around the pintle valve and through this opening, resulting in a fine spray of fuel in the shape of a hollow cone. As a constant pressure drop is maintained across the injector (by the pressure regulator), the length of time that this opening is maintained (injector "on" time) determines the amount of fuel entering the engine and, therefore, the air/fuel ratio.

Fig 1: Cross-Sectional View of Fuel Injector 4 fuel injectors are used on turbo models.