Abstract: This invention provides a method and apparatus for obtaining a uniform advance for an internal combustion engine requiring unequal firing angles between cylinders and is characterized by an electromagnetic pulse generator having a trigger wheel that includes a number of metal vanes greater than a number of cylinders in the internal combustion engine. Although the trigger wheel generates more trigger pulses for each operating cycle of the engine than there are spark plugs only the number of trigger pulses equal to the number of spark plugs are transmitted to one or more switching devices to allow the discharge of stored electrical energy through a respective spark plug in timed relation to the operating cycle of the engine.