Run Mode

Once the engine starts and is operating normally, timing will be controlled by the computer, based upon information received from the data sensors.

Total spark advance is determined by three factors: coolant temperature, engine speed and manifold vacuum.

In a cold or warm engine, as indicated by coolant temperature sensor, RPM has no affect on advance. Under these conditions, advance curve is determined by vacuum signal only. In a hot engine, computer is programmed to consider engine speed in addition to manifold vacuum, to determine total spark advance.