Power to coil but no spark??

[440charger68]

I have a 1970 challenger with a 383 that is getting no spark. Recently it had been running ruff, an found out it was only firing on 6 cylinders. I found the source of the problem for the 2 died cylinders an fixed it, when i went to firer it up it started for about a minute before it died. It would not start back up so i checked for spark at the coil no spark, but it did have one short burst of spark after i stopped turning it over? I checked if their was power running to my coil ballast an their was, then checked the positive on my coil for power an their was power but the light was dim. So i'm thinking it might be the ballast but i am not very good with electrical an any help would be greatly appreciated. Oh an i am running a Mallory comp 9000 dist. an a MSD Blaster 2 for a coil.

Thanks Kyle

[404NOTFOUND]

Could be a hairline crack at the top of the coil allowing the spark to leak out to metal nearby. Have someone crank it over while you watch your coil in total darkness. Mine was arcing to the negative terminal on the coil. A new coil solved it.

[68neverlate]

I have a 1970 challenger with a 383 that is getting no spark. Recently it had been running ruff, an found out it was only firing on 6 cylinders. I found the source of the problem for the 2 died cylinders an fixed it, when i went to firer it up it started for about a minute before it died. It would not start back up so i checked for spark at the coil no spark, but it did have one short burst of spark after i stopped turning it over? I checked if their was power running to my coil ballast an their was, then checked the positive on my coil for power an their was power but the light was dim. So i'm thinking it might be the ballast but i am not very good with electrical an any help would be greatly appreciated. Oh an i am running a Mallory comp 9000 dist. an a MSD Blaster 2 for a coil.

Thanks Kyle

Stock ignition system? 

If you suspect a ballast resistor problem, you can perform a resistance check to confirm.  If memory serves, I think you should get 2 -4 ohms on that.  Hmmm, that's on my '68 (two pronged resistor), might be different if you're running the 4 pronged style for electronic ignition/regulator.  Maybe someone with a '70 will chime in to confirm that.

If you're running an after market ignition system, a lot of those systems want 12 volts (they advise to by-pass the resistor)...

Just thinking out loud...      

[440charger68]

Well i had changed out my coil yesterday with a stock coil and got nothing? I do have a after market Mallory ignition, and my coil resistor is 2 pronged. If my resistor is getting power shouldn't it be good?

Thanks Kyle

[68neverlate]

It depends on the system.  Like I said, many want a full 12 volts all the time.  A properly operating resistor steps that down after start to protect the coil (stock coils are not designed to take 12 volts for long periods of time).  Many after market systems, with their own matching coils, are designed to take 12 volts all the time. 

You may want to reference the instructions on your ignition system to see what it wants.  If it wants 12 volts full time, then your wiring should bypass the resistor.  If not, then the resistor should stay in...   

[440charger68]

Okay so i found some info on my Mallory ignition system, in order to run right it needs a coil that has 1.5 OHM rating. The coil that i have is rated at like a 0.6 OHM so i have to have a ballast resistor that can convert that to 1.5 OHM. So i changed out my ballast resistor with a brand new Mallory Ballast rated for 1.5 OHM an still got no spark, but i have power going to the positive side of my coil but the light is dim. I am now clueless could it be possible that my ballast burnt out, an then over time burnt out my module.

[Cooter]

First off, Why were TWO cylinders dead?
Second, Have you tried checking for 12 Volts at Coil WHEN CRANKING?(you need a buddy here).
Third, have you tried checking to see if you are getting fire out of coil to cap, cap to wire, wire to plug?

[440charger68]

Turns out it was the Module. I had to dead cylinders because my headers burnt through two of my wires, the reason why my module went out was because the guy before put a single field alternator instead of a dual field so the  car ran at a constant 18v so it burnt out my module. Everything else seems fine with the car i appreciate all the help.

Thanks Kyle