An ignition system is disclosed which includes a primary circuit having a battery, the primary winding of an ignition coil and an electronic valve controlling energization of the primary winding by the battery; a secondary circuit having the secondary winding of the ignition coil, a plurality of contacts adapted to be connected to combustion ignition devices and a distributor mounted to sequentially complete electrical connection between the secondary winding and each contact and triggering means including at least one wire mounted on a rotor, the wire having a shell and core of different coercivity, a magnet for reversing the magnetic polarity of the core, and a sensing head for sensing a change in magnetic flux around the wire which is produced in response to the occurrence of predetermined criteria, the sensing head providing a signal for controlling the electronic valve.