The electronic ignition system offers many advantages over the conventional breaker points ignition system. By eliminating the points, maintenance requirements are greatly reduced. An electronic ignition system is capable of producing a much higher voltage which in turn aids in starting, reduces spark plug fouling and provides improved emission control. In addition, the type of ignition system that the Celica uses eliminates the use of a vacuum advance or vacuum retard. The ignition timing while driving is controlled by computer.
The Integrated Ignition Assembly (IIA) ignition system is used on the 2S-E and 4A-FE engines. The Integrated Ignition Assembly (IIA) ignition system consists of a distributor with a signal generator, ignition coil(s), electronic igniter and a micro-computer (ECU). The ECU is programmed with data for optimum ignition timing for a wide range of driving and operating conditions. Using the data provided by the various engine mounted sensors (intake air volume, engine temperature, rpm, etc.), the ECU converts the data into a reference voltage signal and sends this signal to the igniter mounted inside the distributor. The signal generator receives a reference voltage from the ecu and activates the components of the igniter. The signal generator consists of three main components: the signal rotor, the pick-up coil and the permanent magnet. The signal rotor (not to be confused with the normal distributor rotor) revolves with the distributor shaft, while the pick-up coil and permanent magnet are stationary . As the signal rotor spins, the teeth on it pass a projection leading from the pick-up coil. When this occurs, voltage is allowed to flow through the system and fire the spark plugs. This process happens without physical contact or electrical arcing; therefore, there is no need to replace burnt or worn parts.