Ignition Coils (Z261)
The ignition system is a direct injection system comprising of four double ended coils operating on the 'wasted spark' principle. The circuit to each coil is completed via switching within the ECM (Z132), allowing the coil to charge up and then fire. It produces sparks in two cylinders simultaneously, one cylinder on the compression stroke and one on the exhaust stroke. Due to relatively easy ionization of the fuel/air mixture in the cylinder under compression, the coil will dissipate more energy in that cylinder than the other, so very little energy is wasted in the system.
Failure of a coil will result in lack of sparks in two cylinders (coil 1 feeds cylinders 1/6, coil 2 feeds cylinders 5/8, coil 3 feeds cylinders 417 and coil 4 feeds cylinders 2/3). This results in a misfire.