IGNITION SYSTEM CIRCUIT 7M-GE Ignition Switch AM2 IG2 AM2 30A Fusible Link MAIN 2.0L Battery Distributor Spark Plug Ignition Coil Igniter To Tachometer G1 G2 G- NE IGT IGF Engine ECU 7M-GTE Ignition Switch AM2 30A Fusible Link MAIN 2.0L Battery Cam Position Sensor To Tachometer G1 IGF Engine ECU G2 IGT NE IGDA N/C- IGDB Igniter Spark Plug Ignition Coil ELECTRONIC SPARK ADVANCE (ESA) 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 (rpm, intake air volume, eng. temperature, etc.) the microcomputer (ECU) triggers the spark at precisely the right instant.