Seville V8-300 4.9L (1991)
Ignition Control Module: Description and Operation
Engine Speed Signal
The engine speed signal comes from a seven terminal High Energy Ignition (HEI) module in the distributor. Pulses from the distributor are sent to the
PCM/ECM where the duration between these pulses are used to calculate engine speed. The PCM/ECM adjusts spark advance and sends a signal back to
the distributor.
