Toyota Electronic Spark Advance (ESA) Ignition System
The Electronic Spark Advance (ESA) ignition system has ignition timing and dwell angle controlled by microcomputer, which sends the ignition signals to the igniter, where the
transistors inside the igniter cut off the current and generate high voltage. This makes more precise control possible and is the current mainstream ignition system.
The ECU is programmed with data for optimum ignition timing under any and all operating conditions. Using data provided by sensors which monitor various engine functions (air flow sensor, water temperature sensor, air conditioner signal, etc) and distributor (engine speed, crankshaft position detection, etc) the microcomputer (ECU) triggers the spark at precisely the right instant.
The following schematic illustrates the Toyota Supra (7M-GTE) Ignition System Circuit and Wiring Diagram using ESA system. (Click image to enlarge)