Wierd coil issue
 

Ok, what I have is a 12a no porting, 5 speed, rats nest and emissions removed, 2nd gen fuseblock, S5 alt, weber 45 dcoe carb, holley red style fp with ebay fpr and gauge, gilmer drive belt, DLIDFIS with HEI modules and ProComp high output coils, 9mm spiral wound wires and an optima red top battery (relocated behind driver).

ISSUE- I dropped a wrench and broke the posts on my leading coil.:blush::( So, I put the stock one back in to run the leading. However, it is sparking across from + to - and up the post under the boot.

I replaced the coil with the other stock coil and got the same result. I replaced the plug wire and got the same result. I tried wrapping the boot in electrical tape with no help. It's causing my tach to jump at times. I'm stumped at what could be causing this.

Weird one. Is the engine grounding good? Spark plug not fouled?

All I can think of, is that maybe those little electricals just aren't able to get to where they are supposed to go. When that happens, they go where they can instead...

Could also be excess impedance inside your dizzy due to a broken arm or contact...

Ken, wasn't this a symptom back when Ray (or somebody) was busy melting holes in his dizzy rotor? 'Bout a year ago?

Worth a check under the rotor cap, at least. But yes, the symptom would seem to indicate either excess impedance or excess voltage in the secondary.

Ah yes. Now that you mention it, I think you just nailed it. :)

Hmmmm...........
 

I didn't like wiring through the J109's, or having loose plugs hanging off my dizzy, so when I started wiring up my ignition box, I modded the plug for the igniter (drilled out the holes slightly larger, cut the plastic smooth to the dizzy) and wired through the plugs to weathertight connectors and heat shrink of course.:nod: So under the cap looks good.

I'm not sure what you mean about excess voltage in the secondary though. Please explain and how do I test for that.

Here's pics of what I have, so maybe it's easier to tell.

It's difficult to check the output voltage of a coil without special equipment. If you've got arcs coming out from under the HV boot and seeking ground (and at the output voltage of a coil, both the + and - terminals look pretty much like ground in comparison) then either the output voltage is so high it's breaking down & ionizing the insulating air & rubber-to-plastic seal around the coil tower, or (more likely) the arc can't pursue it's intended path out through the HV wire, dizzy, plug wire, plug, and engine ground, to chassis ground.

Had a case a year or so ago here on the forum, where the internal conductive path inside the dizzy rotor (the one that leads from the top button to the "ears") had failed. It was interrupting the flow of voltage through the inside of the rotor, and producing similar symptoms as you have... and additionally, blew a hole out the side of the dizzy rotor due to arc heating, after a short spell.

If the high voltage can't easily make it's way through the normal circuit & back to ground, it will find the next-easiest path. Which can include squirting out from under the tower boot to the primary-side connections.

So, engine-to-chassis ground, chassis ground point, plug contact to rotor housing, Spark plug internal lead, plug wire, dizzy cap, dizzy rotor, HV lead from coil, those are the suspects.

Murphy's Law is a bitch!
 

I hate electrical!:scratch: If it can go wrong it will.:lol: Thanks for the explanation.:nod:
So, first I'll try my other cap and rotor. Then I'll try a new ground from chassis to motor. I'll check the plugs, and if all else fails, I'll pull out the other dizzy I have and pull the igniters and wire it to my ignition module. If none of that works, I'll curse, scream, throw shit and get drunk.:blush::lol:
Thanks for the info, I was at a loss as to what it could be. At least now I have some things to try.

You can test the resistance of your dizzy rotor pretty easy.

The upper contacts should show near-zero ohms connected in two adjacent pairs.

The lower contacts are supposed to be connected internally to the top recessed contact that the spring-loaded carbon "button" inside the cap center rides on.

Naturally, all the contacts on the rotor and the cap should be bright and clean, with minimal to no arc spatter. You can clean them up with crocus cloth if they're not too bad.

Check to make sure the top button didn't fall out, too.

Thanks
 

Thanks, I'll check that today before I start on my checklist.

Holy shit! What a fiasco!
 

Well, finally figured out my coil issue. Tried everything that was listed, but still S.O.L.
Got pissed and went back to the dizzy and worked my way out. discovered a couple of things.
1. my brand new igniter was bad!
2. I couldn't even find my timing marks, it was all over the place. Just for shits I swapped polarity on the igniters from my dizzy and VROOM! I checked my wiring against the diagram in the archives for the HEI DLIDFIS thinking I had wired the modules backward,but it was correct. :scratch: So, I'm going to write up a new thread for the HEI conversion so no one else has to go through this.:( I just spent the better part of 6 days chasing coil/dizzy/carb problems that didn't exist.:icon_tdow Just to be sure, I took replacement igniter, (a different brand than the other two) and wired it as the schematic shows, and I got an idle and alot of sputter. :scratch: I reversed it and purr.. Timing marks are now obvious, and after quick carb adjustment, I can actually give it throttle without it bogging and dying.