the ignitor is supposed to give the coil's a negative pulse, the coils are grounded via that ground strap that's on the coil pack's sub harness, and the coils are given 12 volt ignition power via the grey plug on that coil sub harness as well. if you look at the coil packs it says E + - , e would obviously be signal, - would be constant ground, and + would be 12 volt ignition power (when key is in ON position)