Fuel Injector
The fuel injector is an electrical solenoid, mounted in the throttle body, so that fuel from the injector is directed into the incoming air stream.
Power to the injector(s) is supplied by the SMEC, which determines when and how long the injector should operate. When voltage is applied to the injector, an integral armature and pintle valve moves up 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 conical spray. A constant pressure 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.