Most computer-equipped engines utilize a potentiometer type throttle position sensor to accurately signal the amount of throttle opening to the computer.
Location
The throttle butterfly spindle houses the throttle position sensor.
Function and Operation of the Throttle Position Sensor
When the throttle position sensor is employed on fuel injection, the computer detects any change in the throttle position and modifies the fuel mixture and ignition timing. The computer will pulse more fuel from the injectors because the vehicle functions as an electrical accelerator pump. Throttle position sensors are potentiometer type sensors used to determine throttle opening and rate of change. They have three wires: a 5vt reference feed wire, a ground wire, and a voltage signal wire. The computer uses input to determine the throttle opening and rate of change. The sensor’s resistance reduces signal voltage output to the computer, but the engine may still operate satisfactorily but hesitate upon acceleration.