Sensor

Jaguar: XJS 3.6 from VIN...139052 to 179736 (1987-91) • XJ40 (XJ) 2.9, 3.2, 3.6 and 4.0 from VIN...500001 to 629285 (1986-90)

to detect engine speed and crankshaft position. Fitted to timing cover

This is an inductive type sensor. It consists of a magnet and a coil wound around the magnet. It is triggered by reference points passing the sensor tip. The reference points can be pins mounted to the flywheel in the form of a trigger disc or relucter or on a camshaft. These will divide the 360 degrees rotation of the engine into segments that the engine control can use for the ignition system or for the start of Injection. Each time a reference point passes the tip of the sensor it disturbs the magnetic field creating an AC voltage in the coil.The AC voltage is sent as a signal voltage back to the engine control unit. The crankshaft sensor or engine speed sensor will have 2 or 3 pins. The 3rd pin is used for a screen. The screen suppresses any interference. The engine management light will be triggered if the crankshaft sensor moves outside of normal operating values. A fault with this sensor may inhibit engine startup.