78 bronco ignition coil gets really hot

So I inhearted a 78 bronco ranger XLT from my mom and it will start when cold and idle great but once it warms up it dies. The ignition coil gets really really hot when this happens, once it dies I let it cool for an hour or so and it starts right back up and dies. I have put new plugs, wires, cap and coil on just to replace the old one. My question is what could be causing it overheat the coil and Die? I have read that it could be a balliast resistor wire but I'm not sure any help would be awesome thanks.

Hi BR..., welcome..!

Yes, you're possibly on the right track.

Older vehicles had a "start" on 12v.., "run" on 6v.  This was specifically the voltage to the "coil".

(12v to the points via the coil would eat up the points pretty quick)

You'll have to research if your rig came that way.., or is it a newer style ign. that starts/runs on 12v.

And.., if, in fact, your present ignition is "stock" or aftermarket. Stock would be Ford Duraspark I believe.

Broncos early on, came with an actual "resistor"  prior to the coil. It looked like a rectangular piece

of tile with a resistor on the back.

In the early '70's.., they went to a "resistor wire" which did the same thing.

Only 2 things can heat the coil. Voltage & engine block heat.

My rig is converted to a GM DUI ignition. It starts/runs on 12v.  It also has a 12v coil.

Hey Br,

Check also if the + and - wiring is correct. The wire to the + side of should be red/ green or all red.

If by chance the wires got crossed you could be heating the windings through resistance.

Good Luck

so far from what I can tell is all wiring is correct and is all original. the Bronco will start up and run just fine when cold then once it warms up it dies like someone turned off the key, there is no sputtering or rough idle it just seems to die after about 5 mins like you turn off the key. I have replaced the Coil, plugs, wires and ignition Module so I dunno really boggleing my mind

After it dies.., have someone turn the key to start. (crank the eng. over)

Check for spark at a plug or the coil.

Check down carb throat to see if the jets squirt fuel when throttle is pressed.

"dribble" some fuel or shoot some start fluid in the carb. Move away & try to start.

(Again after it stalls) 

Is the choke stuck/functioning normal..???

If you fill in your info. pages for sure, (see mine below & left of my posts)

& maybe some pic's..., we may be able to fix this much sooner.

After it dies, i can try and crank it but it will not start. There is fuel going into the carb and i can shoot a little starting fluid as well and no start. If i let it sit for about 20 mins and go back and try again it will start right up and run great for all of 5 mins then dies like the key was turned off again.

Where's the spark test info....? And choke insp. info..?

As you may know, it takes basically 3 things to run an eng.

Air.., fuel..., ignition/spark.............

You seem to have air & fuel.., assuming the choke isn't jammed.

So take a hard look at spark....!

With so little info. this becomes a "shot in the dark" guessing game over & over.

Hopefully some other members can jump in with some ideas.

Good luck..,

B