Circuit Description

ECM controls spark timing and dwell (spark on-time) under all engine running conditions. The Electronic Ignition (EI) module has the ability to charge and discharge each of the 2 coil packs independently based on ECM control. ECM uses a high control signal of about 5 volts to charge up the coil and low control signal of about zero volts to discharge the coil. If coil is charged and control signal is low, the coil will fire through it secondary towers.