Ignition Timing: Description and Operation

IGNITION TIMING CONTROL

The ignition power transistor located in the ignition primary circuit turns on and off to control primary current flow to the ignition coil. This maintains ignition timing at an optimum level regardless of various engine operating conditions. The ECM [M/T] or the PCM [A/T] determines the ignition timing according to engine speed, intake air volume, engine coolant temperature, and atmospheric pressure.