Methods and systems are provided for operating a cylinder with a series gap igniter coupled to an ion sensing module. In one example, a method may include determining a location of an initial combustion in a cylinder from a series gap igniter based on a pressure rise rate in the cylinder, the ignition spark initiating combustion in the cylinder; and adjusting at least one setting of the cylinder based on the determined location. In this way, combustion stability and efficiency may be increased without increasing a cost and complexity of the engine.