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On modern engines with computer management there are various sensors to tell the computer exactly what the engine requires in the line of fuel, when to spark the coil/s and so on. The engine needs so fire the sparks at the correct time and also inject the fuel at the right time. So a sensor is fitted to pick up exactly at what degree of rotation the crank is. It is sometimes not even mounted near the crank but still called a crank angle sensor, it can even be in the distributor (Nissan and others) This is in the form of a disc with many tiny slots or holes in it and has a light emitting diode and a light sensing diode either side of the disc,as it turns the light is cut off and the computer detects this and can work out the position of the crankshaft. It can alo be in the form toothed disc much like a gear on the crank shaft or even use the flywheel to sense the position using a hall effect sensor to detect the positon of the flywheel or crankshaft pulley to determine exactly where the crank is positioned.

It is a sensor that tells the ecm where #1 cylinder is. They are located on different parts of the engine on different cars.
It reads the position and/or speed of an engine as it is rotating.

When crankshaft is turning, the sensor will provide a signal to the PCM. The PCM will then allow the engine to start by providing spark and fuel.
It reads the rotational position of the crankshaft

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2010-05-16 16:14:34
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Q: What is a crankshaft position sensor?
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