ESA Systems

The Electronic Control Unit (ECU) is pre-programmed with data for optimum ignition timing under any engine operating condition. Using data from engine sensors (RPM, engine temperature, etc.), the ECU triggers ignition system to provide a spark at precisely the right instant. The ignition system operates on the same principles as a non-ESA system except all timing advance is controlled by the computer rather than by vacuum and mechanical advance mechanisms.

The ECU uses a tachometer signal from the ignition system to detect engine speed and trigger the fuel injectors. Some ignition system problems can be detected by the ECU and will result in a trouble code No. 12, 13 or 14 being set in the computer memory.