Ignition Coil Grounds

Hi, long time listener, first time caller here

On my 85 XJ700 the previous owner popped the 30A main fuse, but instead of replacing and finding the short he just spliced the wires together.(!!) My spider sense went wild and I figured if he did something like that there is no telling what else is off with the wiring. So I am replacing the whole harness (Ebay score, woot!).

Pretty hassle free, except on the old harness there is only one ground wire going to a single ignition coil. So my question is, is that wrong? There are screws in the frame that look like ground screws and the metal eyelet on the lower part of the igniton coil look like it has screw marks.

Is it correct for the both ignition coils to have grounds from the harness on top and then grounded to the frame at the bottom? Maybe that's why he kept blowing the main? Or is it correct as is, with a single ground wire to a single coil?

 

Coil grounding (of the coil core laminations) is for noise reduction... it has nothing to do with firing the coils. As long as the mounting bolts are connecting the two coils together, one ground wire for the pair of them should be fine.

The two pin connections to the harness for each coil supply +12V and a switched line that goes to the TCI. No ground.