there is a fat ground wire going to each coil through the harness.
Yes, but it connects to the coils inside the package, and does not touch the iron core/slats. I was just worried about whether the core needed to be grounded. Seems to be a no, but I may do something anyway, JIC.
Warning, long:Well, there are 3 wires. They are all the same size (according to Chilton), and are as follows:
Pin 1) 1mm core Black. This is the negative side of the primary coil, and is grounded momentarily only when the motronic grounds it through a switching transistor. The rest of the time it sits at 12V because of: Pin 3
Pin 3) This is a 1mm core Green wire that is directly connected to the 12V supply switched by the key/ignition switch. It is the positive side of the primary coil.
Pin 2) This is a 1mm core Brown/Orange wire. It connects the secondary coil to the ground distribution point. The secondary has neither a positive nor a negative side in this application. Two sparks are actually made upon each ignition event triggered by the Motronic. Each one going in the opposite direction, one after the other. This is from the generation of the magnetic field in the ferrous core upon the grounding of the primary coil (creating a current in one direction), then the immediate collapse of that field when the ground is cut off again, stopping the current flow in the primary, and causing a current in the secondary moving in the opposite direction.
