Crankshaft Sensors

A crank sensor is an electronic device used in petrol and diesel internal combustion engines to monitor the crankshaft's position or rotational speed. Computer boxes or ECUs use the information gathered to control fuel injection, ignition system timing, and other engine parameters. Before electronic crank sensors were available, the distributor on petrol engines had to be manually adjusted to a timing mark.

The crank sensor, along with a similar camshaft position sensor, can monitor the relationship between the pistons and valves in the engine. This is essential in engines with variable valve timing. When starting, this method is also used to "synchronize" a four-stroke engine so the management system knows when to inject fuel. The crank sensor is often used as the primary source for measuring engine speed in revolutions per minute.

The sensor can be mounted on the main crank pulley, flywheel, camshaft, or crankshaft. Along with the camshaft position sensor, it is one of the two most essential sensors in modern-day engines. Since the fuel injection (diesel engines) or spark ignition (petrol engines) is usually timed from the crank sensor position signal, a failing sensor can cause the engine not to start or to cut out while running. The engine speed indicator also takes speed indication from this sensor.