Abstract: An ignition control system for an internal combustion engine has a coil connector for connecting to an ignition coil, a processor coupled to the coil connector, and a memory coupled to the processor. The memory contains instructions for the processor to, in communication with the ignition coil, achieve and maintain a target spark duration by dynamically controlling a coil dwell set-point of the ignition coil. The processor energizes the ignition coil during a first ignition sequence based on the coil dwell set-point, directly measure spark duration of the first ignition sequence by monitoring a voltage reflection on a primary side of the ignition coil, adjust the coil dwell set-point for a second ignition sequence based on the target spark duration and the measured spark duration, and energizes the ignition coil during the second ignition sequence based on the adjusted coil dwell set-point.