Another bad coil?

[Tyman]

Hey guys, having more electrical problems!

My truck kept dying, narrowed it down to bad coil. Was getting 12v with key on to + side of coil, and the other side was flashing the 12v test light as I cranked it over but was getting no spark from the coil. The coil wire to dist cap is good. So I went to the auto parts store and got a MSD coil. Fired right up!

But now after about 20mi total of driving it dies again, with same problem! I can't figure out what it's issue is. It's getting power, is it something to do with the dist? I have a pertronix ignition.

Really really need help, stranded and can't get to work. Thanks!!!

 

[Viperwolf1]

Put some points back in it. That's a key selling point of the pertronix. When it fails you can put points back in to drive away.

 

[RangerRob]

Make sure your coil is rated for 12v and that it doesn't need a resistor inline (either ballast or original resistor wire). I know the Pertronix needs the full 12v, but your coil may not and it may be burning it up.

My setup has a Ballast Resistor before the coil, but I pull the Pertronix feed off of the high side of the resistor. It's been working fine like that for 20 years with the same coil (Accel Yellow).

Good Luck!

 

[Tyman]

Put some points back in it. That's a key selling point of the pertronix. When it fails you can put points back in to drive away.

You think the pertronix might be failing?

And I haven't used a ballast resistor in this thing for like 6 years just recently started doing this.

Are coils not supposed to be getting 12v?

 

[broncoman805]

Your burning up the coil. As stated by RangerRob you need a resistor.

 

[Tyman]

Thx. How come I didn't need one before, was it just luck?

 

[Viperwolf1]

You think the pertronix might be failing?

And I haven't used a ballast resistor in this thing for like 6 years just recently started doing this.

Are coils not supposed to be getting 12v?

I think it's the pertronix. A coil can burn up quickly like that but usually only with points closed and the ignition left ON but not running. Your points won't last very long without the resistor but it'll get you by long enough to get to work and buy another pertronix.

 

[Tyman]

Guess I am confused, how could it be pertronix though if I'm not even getting power from the coil? Ballast resistor makes sense. Looked up the coil I got and it says 0.8ohm resistor MUST be used...and I don't have one just full 12v from ignition side of selonoid

edit: Misread it, says ballast resistor must be used with points, I don't have points

 

[broncoman805]

You think the pertronix might be failing?

And I haven't used a ballast resistor in this thing for like 6 years just recently started doing this.

Are coils not supposed to be getting 12v?

Did you replace any wires to the coil? Ford uses inline resistor wire.

Try a Petronics Flame Thrower coil.

 

[Tyman]

It's been so long can't remember. But I'm sure I used to use a ballast resistor when I had points long long ago. Then it's just been 12v ever since for atleast 6 years with the pertronix

 

[chadomatic]

I will second the flamethrower coil it is designed to run with a pertronix with no resistor in a v8.

 

[Tyman]

Well just walked up to Baxters they told me you can't use MSD coil with Pertronix ignitor. Will burn out the pertronix or coil. Bought new flamethrower coil, got back took off dist cap...smells like burned electronics. So new coil didn't help, but will keep this one so I don't burn out another pertronix! Now back up to the store to spend more money!!!

 

[broncnaz]

Almost all coils need a resistor and most of the ones that dont need it either have it built into the coil or the igintion system it is intended for has it built in or only pulses power to the coil when needed. Many times you can have a coil last a long time without a resistor before it decides to fail. I'd say that todays coils are probably not as well made as older coils were and tend to fail quicker. Sometimes they just stop working other times they blow up or at least blow the cap off enough for the oil to start leaking out.

 

[Tyman]

What the hell! Just bought a flame thrower coil, no start no spark. Then just got a new pertronix. Still no start or spark?? I'm getting power to the coil so freakin confused. Any ideas?

 

[Viperwolf1]

Put a set of points in it so you can tell what's happening or not happening.

 

[Tyman]

Figured it out, I didn't set the airgap! Fired right up after that. Thanks for the help guys, so new flamethrower coil and pertronix ign, should be A-OK now I hope

 

[Viperwolf1]

Carry a set of points.

 

[Tyman]

Yeah I probably should, but need to have a reliable vehicle now days so going to just put this for sale

 

[Justafordguy]

Don't do that, just make it more reliable.;D