Engine Controls

Computer commands are carried out by solenoids, motors and other control devices. Solenoids are used to control vacuum, air bleeds, the carburetor fuel flow, etc. Motors are used for the idle speed control and mixture adjustments.

Some computers control functions directly, while others use indirect means. For example, when a detonation sensor hears "knocking", the computer will retard timing. On some systems, it will tell a solenoid to cut off vacuum to the distributor vacuum advance solenoid. Timing is retarded. On other systems, the computer may be directly involved in controlling engine timing, and it just retards the firing slightly until "knocking" stops. The method used is different, but the effect is the same.