Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

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Engine Speed Sensor: Description and Operation

Engine speed and crank position are monitored by a sensor which is mounted on the cylinder block (flywheel housing) in front of the crankshaft drive plate. It indicates rotational speed to the ECM in the form of 35 pulses per crank revolution. Engine speed is used for synchronization of fuel and ignition systems, as well as other functions.