Tachometer: Description and Operation

Turning the ignition switch to ON (II) or START (III) turns ON the tachometer driver in the gauge assembly. The tachometer driver receives pulses from the Ignition Control Module (ICM) in the distributor assembly. The solid-state tachometer then displays these pulses as engine speed. For each 200 pulses per minute from the ignition control module (ICM), the tachometer displays 100 RPM.