Brief Description

This system uses similar circuits between the ICM and the PCM that a distributor type system uses.

Following is a brief description of the IC circuit. The PCM sends the Ignition Control (IC) pulses to the ICM on the ignition control A & B. The signals are similar to the 7x reference pules square wave except that the PCM uses the sensors inputs to determine the pules timing to control spark advance.

When the PCM receives the 7x reference signal, the PCM determines which pair of cylinders to fire 1 and 4 or 2 and 3.