Technical Petronix ignition problems

I have been through 3 ignition modules on this 53 chevy I'm building.. The car runs and starts perfect, and then at a random time it won't start, the little red module in my distributor is blown.. I have good grounds with almost 0 ohms everywhere I check.. I'm running 7mm spark plug wires for autozone, that iv run on all my other cars.. I believe it's wired right iv checked it over a few times but I could be missing something?? Any help would be much appreciated!! Thanks in advance

 

Edit - I guess if it's a red unit, it's probably Ignitor II and is supposed to protected from key left on damage. So it looks like my theory is out.

 

These other threads about Pertronix may help you.
Also, does Pertronix recommend a surge protector like Mallory does? It
protects the module in case of a voltage spike. Also, does your Pertronix require a ballast resistor? Give them a call.
http://www.jalopyjournal.com/forum/search/52744672/?q=pertronix+installation&o=relevance&c[node]=5

 

Are you running the exact coil that goes with your Pertronix?

 

Good point. Coil matching is very important with any electronic ignition.

 

Thanks I will check that!

 

The coil is right I believe!

 

Is it a flamethrower coil?

Another thing you never wamt to do is leave the key in the on position while checking things out. HRP

 

You need a 1.5 ohm resistor and a 1.5 ohm coil. 3 ohms total resistance. At least that is what I have been told.

 

i believe that 3 ohms may be for the Ignitor , i think the Ignitor 2 needs less resistance

you better check the directions to be sure

 

Call their tech support. They have always helped me.

 

^^^ And I always use their coil with their unit. Never a problem.

 

Yes it's there flame thrower coil.. Car is always off when I check resistance, I checked resistance and it was around 2.8, minus my meters resistance which was 1.8 I was left with 1 ohm... after running a ground strap to the distributor from the chassis I have 0 ohms.. iv never had to do this on any other cars iv done, so maybe I'm missing something else, I'm lost lol

 

I believe the flamethrower ignition coil that is mated/matched the ignitor II should be .6 ohm on the primary.

 

You can't power anything other than the Ignition from the positive feed to the coil . if you also for instance power an electric fan or anything from that circuit , it can backfeed to the module . their tech support made that point loud and clear to me

 

Coil needs to be 1.5 ohms at a minimum. Doesnt have to be pertronixs most of the electronic units using a .6 (example) draw too many amps and overheat the module. See it every week !

 

Thanks for your input GMCBubba! You teach us all something new all the time.

What ignition coil with a 1.5 ohm primary or lower would you recommend (e.g., Echlin IC12)?

 

First if you are getting 1.8 ohms resistance on your meter with the leads connected to each other this is too high, should be zero, or maybe .1 but zero is the norm. Make sure the leads are good. Then the resistance you are checking that changed with a added ground to the distributor housing, where are you placing the leads exactly when you are making this test? Granted, the distributor housing gets its ground normally through the hold down clamp and bolt, if you have a gasket between the distributor housing and intake manifold. So if the housing is painted this could cause an issue with the ground path.

 

If you are still having problems after following the advice in this thread, contact hotrodon on the HAMB. He works for Pertronix and will work with you until you're up and running with no problems...he is AWESOME!
(as is everyone here....the power of the HAMB rules)

 

Several issues that come up constantly when converting to Pertronix. I and II are different where I's burn up (from key being left on) and II's don't. ohm resistance for II's need to be at the 1.0 range, I's are at 3. The 'ring" may set too low to work properly and it has been suggested to place a washer underneath it to raise it to the proper level. I put a set of II's on my 440 GTX and it quit running. Spark was all over the map. I'm back to my original distributor.

 

Just checking for ohms resistance between two connections won't tell you much, if anything. What you could try, I guess, is for voltage drop. For example, in parallel between a connection. Has the engine been painted/restored? Just a wild ass guess. Maybe there isn't a solid ground reference on the distributor to block.

Solid state electronics is "pretty tough" but they don't like poor grounding or backfeed or, AC ripple probably. Maybe check your alternator for a bad diode. Let us know what you find. I've run an old ignitor and generator system for about 17 years. Managed to burn up a coil (it started leaking anyway) once in that time though it still worked. Thing is, a points system can do the same thing. In fact the only reason I got rid of them points, Ford put the distributor way at the back of the engine, and I'm not much of a contortionist. And whose idea was it to put a generator down low like that? It was doin' fine right where it was on them old flatheads.

 

I have had them on 3 different vehicles for years with no problems. Used their coil with all of them. Check your alternator output, maybe it's too high.

 

If you match the Pertonix coil to the module, you should not need a resistor. Make sure you don't have a resistance wire running from the ignition switch. The instructions are straight forward.
They should sell these as a kit with coil included and no resistor anywhere in the system.

 

NAPA IC12SB good unit at 1.5 ohms

 

Thought id try a ignitor 2 and lasted one month. Iuse the petronics 1 in 2 of my others cars and some are over 10 yrs old. So. Put a petronics 1 in and no problems. Just don't leave the key on to long. I do run ballast resistors in them.

 

GMC Bubba, thanks again for all your help! I do have a question based upon your previous post.
"If 1.5 ohms is the minimum, what would be the maximum"? Just curious.

 

I had the same problem with Accel modules. Fried two before calling tech line. They said I should ground the module to the firewall, not the engine. Made absolutely NO sense to me but I did it. Haven't had a problem with the modules in the last two years!! Go figure.

 

You ABSOLUTELY CANNOT LEAVE THE KEY ON!!!...when not running. Been there...use MSD next time.

 

When the ohms goes the other way the coil and primary current goes DOWN not up ! A 3 ohm coil would operate at 4 amps on a 12 volt system. A 4 ohm coil would operate at 3 amps. Most V8s need a minimum of 3-4 amps. As amps goes down the spark just goes out!!! We ocassionaly do this on a tester and run the rpm up unitl the spark goes out etc, same effect the time isnt enough at lets say 8000 rpm for the coil to supply good spark....
Another example is four cylinders , there is more time to build and fire than on a V8 . The flatheads fall into their own world as they are typically used in a low rpm band of operation....

 

Thank you for adding clarity.

I believe the max amps for a Pertronix II module is 20 amps (I can’t find this in my notes, but believe I remember this from a conversation with Pertronix Technical Support). If one uses their advertised coil at .6 ohm with 12 volts one ends up with 20 amps (no ballast resistor). However, most of our alternators put out somewhere around 14 volts which would end up with 23 amps using their .6 ohm coil exceeding the max amps.

Your suggestion of using the minimum of a 1.5 ohm coil (ECH IC 12sb) would limit the amps to around 9 in a 14 volt situation ensuring the module does not get too hot. So, based upon 14 volts one could run around a .8 ohm coil maximum.

If I am interpreting your comments correctly, by using the ECH IC 12sb coil will not get the most out of the ignition system but should ensure longevity of the ignition module (please correct me if I am wrong).

Thanks again for all your comments and posts.