Supra Turbo
The distributorless ignition system uses the Electronic Control Unit (ECU) for determining ignition timing (spark advance). The ECU determines ignition timing (spark advance) based on various input signals. Various input signals which may be used are coolant temperature sensor, airflow meter, engine RPM, throttle position sensor, vehicle speed sensor, neutral switch, A/C switch, cranking (starter) signal and knock sensor.
Conventional distributor and pick-up coil have been replaced by a camshaft position sensor. Crankshaft position input signal is delivered to terminal G1 and G2 of ECU and engine RPM input signal is delivered to terminal NE of ECU. See Fig 1.
The ECU uses 3 ignition primary control signals for the ignition coils as IGT, IGDA and IGDB terminals of ECU. The ECU monitors the IGF circuit to ensure ignition coil has fired.