The electronic ignition on the normally aspirated engines is a fully transistorized, high energy system. On 1990–92 non-turbo 2.2L engines, it is a conventional electronic ignition system in that it operates with both centrifugal and vacuum advance mechanisms controlling ignition advance. The ignition timing is advanced by vacuum at low speeds and by the centrifugal mechanism at higher speeds. Proper engine performance and satisfactory exhaust emissions are controlled by the ECU.
The ECU controls the electronic ignition on all other engines including, the turbocharged 2.2L engine. The system is entirely electronic. The ECU sends the spark timing signal through the ignition module to the distributor based on its triggering signal from various sensors and switches. The sensors and switches include the following:
Other non-electronic components in the system include the starter interlock switch, battery, distributor, spark plugs, high tension leads and ignition module. The distributor provides a signal to the ECU to indicate crankshaft top dead center by means of its cylinder TDC sensors.
Both systems operate in the same manner. The power relay closes and changes the coil primary windings when the ignition switch is turned ON. When the engine is running, the ignition module grounds the negative side of the coil primary circuit which induces spark. This results in an inductive charge built up in the secondary circuit. Then the spark is sent to the distributor where the rotor and distributor cap work together to deliver spark to each spark plug.