On any four-stroke engine, a full cycle is completed in two crankshaft revolutions - once the piston approaches top dead center at the end of the compression stroke, the second time - at the end of the exhaust stroke. This makes it possible for injection engines to use only the moment of reference from the crankshaft position sensor as a reference signal.

1. 3 (E36)
2. 3 Saloon (E36)
3. 3 Coupe (E36)
4. 3 Compact (E36)
5. Z3 Roadster (E36)
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The camshaft sensor functionality

The VALEO brand Sensor, camshaft position gives one impulse per shaft revolution. Since the camshaft rotates twice as slow as the crankshaft, we get an accurate mark that determines the intake stroke on one of the cylinders. It is very easy to calculate the injection timing for the cylinders of the injection computer.

But injection phasing is not the only thing the camshaft sensor is responsible for. Since the injection ECU can easily calculate the time delay between the moment of the start of counting according to the crankshaft sensor and the moment of receiving the pulse from the camshaft sensor, it also becomes possible to determine the real position of the camshaft relative to the crankshaft.