Ignition Coil: Description and Operation
DESCRIPTION AND OPERATIONSix Tower Coil Packs:
The ignition coil pack contains three separate ignition coils which are controlled by the Ignition Control Module (ICM) through three coil leads. Each ignition coil fires two spark plugs simultaneously; one plug on the compression stroke and one on the exhaust stroke. The spark plug fired on the exhaust stroke uses very little of the ignitions coil's stored energy. The majority of the energy is used by the spark plug on the compression stroke. Since these two spark plugs are connected in series, the firing voltage of one spark plug will be negative with respect to ground, while the voltage of the other will be positive with respect to ground.