024 L4-135 2212cc 2.2L SOHC VIN B 2-bbl (1982)
Electronic Spark Control Module: Description and Operation
The Spark Control Computer is the heart of the entire system. It gives the capability of igniting the fuel mixture according to different modes of engine
operation by delivering an infinite amount of variable advance curves. During cranking, an electrical signal from the distributor is fed into the computer.
This signal will cause the computer to fire the spark plugs with a fixed amount of advance. Once the engine starts, then timing will now be controlled by
the computer based on the information received from the various sensors.
The amount of spark advance is determined by three factors: coolant temperature, engine speed and manifold vacuum. The computer determines spark
advance in the following manner:
1. Coolant temperature modifies the vacuum advance schedule. There is a different schedule for hot and for cold engines.
2. Advance from vacuum is programmed into the computer. In a cold or warm engine, vacuum advance depends only on the amount of manifold
vacuum. In a hot engine, vacuum advance depends on both manifold vacuum and engine speed.
3. Advance from speed is programmed into the computer and depends only on engine speed.
