MSD/HEI problem
 

Hey gang I recently had to replace my oil pump. I had to get my pan off so I took off my HEI dizzy to make room between it and the firewall. A friend of mine hooked up my MSD 6al box and when we first hooked it up we could see it arc'ing somewhere. so we shut the car off and took the cap off checked it all out it all looked fine so we put it back together and it seemed to be gone. Car ran great everything seemed ok. Few weeks go by and as I said earlier I had to replace my pump so when I took that dizzy hei cap off I noticed that the wires were melted on the coil ( mind you the car was still able to run before I seen this) I was surprised and thought how in the hell could this thing still be running. So upon further inspection I see that he has the orange wire to the batt. terminal of the dizzy and that is correct from looking at the msd wiring diagram. Then I look at the black wire coming from the msd to the dizzy and its hooked to the Tach side. This is where I am not sure if its right and may be the reason for the melt. From reading the MSD instructions in regards to MSD to HEI the black wire is supposed to hook to the coil negative side. So I am thinking he should have hooked it up that way instead of to the dizzy tach side? If it is supposed to go to the ground how did it still seem to run fine? I am just a little confused. I also read some where that the tach on the HEI is a ground? Is that true? Any help here would be greatly appreciated before I put my new coil in I wanna get this straight so I dont melt wires on another one.

Re: MSD/HEI problem
 

I can see by the way it looks like the black wire into the dizzy that it kinda looks like it is hooked up to where the tach would be.
but it says Connects to the negative (-) terminal of the coil.
This is the only wire that makes electrical contact with the coil
negative terminal. It doesnt say anything about hooking it up to the tach side.

Re: MSD/HEI problem
 

The chart does though say at the bottom Black connects to c- is that the Tach part of the HEI listed on the cap? I will post a pic of where the coil wires melted before I head to work tomorrow.

Re: MSD/HEI problem
 

Magnetic pick up = tach signal
C - = complete tach circuit for msd? ?


Interested in the melt down

Re: MSD/HEI problem
 

Heres the pic I took this morning. I wanna make sure I get this straight before I hook up the new coil. I don't wanna melt another. Attachment 349006

Re: MSD/HEI problem
 

The car was still running with using that lol. Dont ask me how, but it was.

Re: MSD/HEI problem
 

I called MSD today and it was hooked up wrong the black wire does not go to the Tach and thats probably where the melting came from lol.

Re: MSD/HEI problem
 

OK ordered a MSD Street Fire Coil from summit and just got here today. So tomorrow gonna hook it up and see how it goes.

Re: MSD/HEI problem
 

ok so I may have replied prematurely on that post about the black wire not going to the Tach on the dizzy. When I called MSD the guy tells me no the black wire from my 6AL goes to the c- and that is true it does go there, but it can also go to the tach on the dizzy. c- and tach are the same yellow coil wire. My friend that hooked it up put it on the tach. terminal instead of the c- ( I dont have my Tach hooked up yet)but it will run just the same as hooking it to c- since its the same wire on the coil. I posted the pic below showing what I mean about tach and c- being the same yellow wire. I did also find out that my melting problem was from a lack of a good ground. We didnt have the grounding strap hooked up. So hopefully no more melt problems with it now that I have it properly grounded.


Attachment 348689

Re: MSD/HEI problem
 

Glad they helped!!
Sorry it cost some $ to get it straightend out cor the coil & dizzy!
Thanks for the information & the PM!!