Crankshaft Position Sensor: Description and Operation

Fig. 31 Control Signals Diagram:

Fig. 22 Plug I.D.:

The engine speed, and cylinder reference sensors are located on the upper left side of the transmission bell housing, directly above the flywheel. The speed sensor is a magnetic pickup that produces 135 impulses per engine revolution, (one impulse per flywheel tooth), Fig. 31. These impulses are used by the control unit to determine the engine speed and the ignition timing point.
By means of a pin in the flywheel, the reference sensor sends one impulse per crankshaft revolution, at 60° BTDC. This signal is used by the control unit (along with the Hall sender in the distributor) to identify TDC for cyl. #1.
The reference sensor and speed sensor are connected to the control unit wiring harness near the ignition coil, Fig. 22. The connectors are mounted to a bracket connected to the ignition coil.