Top Dead Center (TDC) Sensor/ Engine Speed Sensor
The Top Dead Center (TDC) sensor is mounted next to the flywheel/drive plate. See Fig 1. The TDC sensor is nonadjustable and senses TDC, BDC and engine RPM. Two teeth on flywheel are machined off at 180 degrees apart to define a precise point, 90 degrees before TDC and BDC. The TDC signal is sent to the ECU where its input is used to compute the ignitione output signal. See Fig 2.