Unexplained Episodes of Stalling

What is the primary resistance of that coil?? If its getting blazing hot you should probably keep the ballast resistor.

1989sn2001_985 wrote: original prestolite ignition module I bypassed the ballast resistor as indicated in the Prestolite instructions. But that thing gets hot! Is that normal? The instructions seem to indicate that a lower resistance coils with a bypassed resistor is what is needed. Thoughts?

No, a burning hot coil is NOT normal!

So the instructions say bypass the resistor but if the coil gets not don't bypass the resistor? Rhetorical question, the Prestolite instructions (or lack there of) suck. The Prestolite has 2 wires. One tach one RESISTED voltage. The Mallory has 3 wires. One ground, one full 12V and one RESISTED voltage.

Why are you risking burning up yet another module by wiring it the same way as before?

1989sn2001_985 wrote: It's a low resistance coil, I believe 1.5.

Well then use the ballast. That is the same as the factory Prestolite coils that all used ballast resistors.

1989sn2001_985 wrote: putting ballast resistor back in place, and running ignition module directly to 12 volt source.

This makes as much sense as eating ice cream on a diet.

MSD coils are .7 ohm. Pertronix Flame-Thrower II coil is .6 ohm. I'd really call these low resistance coils.

The #1223 coil from skidim [COIL IGNITION (FORD/GM) STANDARD IGN.
Point Type Ignitions (Used with external resistance)] is advertised as 1.5 ohm. This is basically a stock replacement for the original Prestolite coils used with points & ballast resistors.

Skip to the #1230 PCM PowerPlus coil [COIL ELECTRONIC IGNITION c/o Prestolite, Mallory or Pertronix Breakerless Electronic Ignition System] does not have an advertised resistance. I have one however and measured 1.5 ohm. So, there is no difference between this one and the first one, besides being $10 cheaper.

The whole business with bypassing a resistor for conversions is to get 1.5 ohm resistance (relied on solely from the STOCK coil) for the Prestolite (purple wire) EI conversion module. Sorta the same thing for the Mallory conversion, except it wants both full 12V (red wire) AND 1.5 ohm resisted supply (black/green wire).

Stock points setup gets .8 ohm resistor + 1.5 ohm coil.

Situation 1: Burnt ignition module
If bypass your ballast resistor and you use a low resistance coil (MSD or Pertronix) with a Prestolite or Mallory conversion you'll burn up the module. (SNobsessed is currently proving me wrong on this however). Failed modules make for sporatic running before complete failure.

Situation 2: Hot coil
Stock Prestolite, #1230 from skidim or PCM PowerPlus coils will burn up if you bypass the resistor. The points can take the lessened resistance (a total of 1.5ohm) but the coils cannot take the full 12V. Result is poor running warm/hot engine, runs fine cold.

Situation 3: Upgraded coil with points (hasn't seemed to be an issue here)
MSD and Pertronix coils can take 12V, unresisted. However, when running points and a low resistance coil MSD recommends adding in a .8 ohm ballast resistor, netting a 1.5 ohm total resistance. A low resistance coil only will probably burn up your points pretty fast.

Hollywood, greatly appreciate the time in explaining the situation and scenarios.   I do indeed have the PCM coil (number 1230 from SKIDIM) and the Prestolite Conversion (with recently replaced ign. module) so will proceed with the recommendation of getting that ballast resistor back in place before the next run.

GottaSki, right on. My novice mind would have expected the opposite of "extra heat that develops when the total system resistance is too low" but there you have it...makes sense.

Thanks again to you both for your direction through this, I appreciate it.

wow, talk about a parts changer!

Trader144 wrote: 2. Replace coil with a new one

Again, this won't fix the issue if you're using the wrong coil from the get go.

Yay.