Technical New guy with odd electrical problem

Isn’t a Pertronix supposed to be the answer to ignition problems? Not an element of one?

 

Reading through all of the replies and suggestions, two things stick out to me:
1) Whatever problem is a heat related issue. When cold or not fully warmed up the engine runs fine. Once the fan kicks in at normal operating temp is when the ignition stops working.
2) A coil boiling out oil is too hot. I think running straight +13.x volts is too much. Unless the coil is one designed with internal resistor. Some are designed with that, no idea if yours is or not.

Try this when it acts up. Remove distributor cap and try to see what the Pertonix module feels like temp. If too hot, that could be your issue. You would need to talk to Pertronix to find out what temp is acceptable. With a blower you are probably getting a little warmer in the distributor area than without a blower.

Try a ballast resistor on the line feeding the coil. Can't hurt and should help that from running so hot.

 

Old Lerker here. Just an observation. My son has an OT car of foreign manufacture. He recently had a fail while driving home from work. Sat for ten minutes, started fine, drove home. No problem for several days and then did it again. He went online to OT car's forum and found the fix. It seems that there is a circuit board under the dash. Some of the board connections are poorly soldered or break with time. Resoldering them fixed him up. Engine heat would make the board flex (on the firewall) and open circuit.

 

Just a thought , How many amps does the fan pull ?
My combo Roots blower Electric Only

I was having a drain issue with engine running , 100 amp alt , 6 ga from Alt stud to starter , 0 cable from bat to starter & 0 grand to frame & plus double laced grounds engine to frame, Red top Ultima bat... No lights on, MSD, Etc fuel pump , 14.2 or so Vots ,
When Fan Kicked on Volts would drop to 12 volts in 5 mints ( idle) above 2,000 rpms , fan on would drop from 14.ish to
Right around 13 v some times 12.8 ish..

The Fan I have is a Spale , it pulls 43 amps when On ,
Fix was to change out the Red top witch has a Reserve of I think was 30 mints @ 55 amps
The Yellow Top is like 60 mints , or waybe also 120 mints
@ 75 amps ,
The mints & amps are off top of my head / memory ,
But the Yellow solved my issue @ Idle..
In stop & go traffic Fan On @ Idle

 

Just curious, did you try a ballast resister? Regardless of what Pentronix said, it sounds like you checked, double checked, replaced and made some repairs without finding the answer.

 

Suggest using an analog voltmeter to check voltage drops but if the lights go dim while cranking there is no need for a voltmeter there is a voltage drop. Check your new battery again. Flashing lights or do they just go dim or out completely while cranking?

 

Have you even just tried throwing a set of points in it?

 

Wow, I really wish I would get notifications for this thread. I do have them turned on. I got one Friday and didn't think anyone else responded then open it up to whole page of suggestions added, lol. I'll try to respond to all these, but may have to get back to some tomorrow.

 

The wire to the alt I believe is a 10awg. It was supplied with the harness. I have another car with a similar 1-wire alternator that has a 10awg ran from a rear mount battery to the front probably at least twice the distance and much more electrical components of this car that has been running without issue for years. All the wiring was supplied with the harnessexcept for the pre-made battery cables from o'reillys. Battery is directly under the passenger seat, fuse panel above the steering column in a model a. Longest cable is maybe 6ft. Not going to say it can't be the harness wires, but if it was I would suspect a lot more people using the same harness would be having similar issues. So far, it's just been the one battery that failed.

 

I would love to do that, unfortunately I don't have access to that equipment or know anyone who does. I have asked a couple shops, but they either have the same suggestions we have all gone over, or say bring it in, the shop rates are only an arm and half a leg, lol.

 

At this point, I won't say the pertronix is the problem. It seems that something else is tied to all of this that I can't find in the wiring harness.

 

The car runs fine for a time at normal temp as well. The last time I drove it, it was already at temp before going the 13 miles. It ran great like nothing was wrong until it was like someone reached down and turned the key off out of nowhere. The last time it was running and the coil leaked, it was at 190-200° idling fine. If I wasn't sitting where I could see the coil dripping, I would have not known something was wrong. Unfortunately I cannot get to the distributor easily right when it acts up. According to pertronix, if it was the module getting to hot, once it failed and shit the car off, it would not start again after it cools. Once the module fails once, it's done. They also said the stickers on the module are like shrink tube. If they are still on like normal, it didn't get too hot, but if they are discolored and curling up, it's a sign of failure. This one still looks fine and the car will start tight up.
The coil itself is internally resisted @1.5ohm per pertronix specs.

 

There is no circuit boards on the car. Only the fuse block which I have tried moving all the wires o the back of while the car was running the last time I had the cowl off. I did not have any loose connections and I was unable to make the car shut off while doing this. I did this not only at the back of the fuse panel, but all around the harness under the dash, near the ignition switch wires, coil wires, headlight switch, and gauge wires. Nothing affected the car.

 

Fan I believe was rated at 25amps. It has a 30amp fuse I line and hasn't popped it. I have not seen a voltage drop when the fan kicks on whether at idle or driving. If your paying very close attention at idle, you can tell when the fan kicks on, but even with a volt meter on the alt, the voltage doesn't fall.

 

I haven't tried a resistor yet. I need to find something that will work without dropping the voltage too low. I have been looking for voltage drops with my meter but have yet to find anything significant. I have read that anything over 0.2 on the ground side is concerning. So far everything I have found is 0.0-0.1.
I wish I could post a video, the l.e.d. lights do not go completely out, but dim. They dimmed less once the battery and starter were replaced.

 

I have thought about that. I was going to go that route if the car didn't start when I put the last module in the distributor. If I go that route, I will probably just get a new distributor w/vacuum adv to swap in.

 

Well, this tells me power delivery is not the issue then if you can click 25 amp draw fan on without voltage fluctuation.

Another idea, floating ground on distributor/alternator or bad connection can do weird things.
Take a 10 gauge wire from the negative of the battery with about 10 ft long, TEMPORARY vice grip attachment is ok as long as surface is clean. Then touch to the distributor base, see if the lights do anything different, Also try touching it to the case of the alternator? If that wire sparks etc, you have a ground issue indefinitely.

You can also try disconnecting the battery, and Ohm meter the main power to the fuse panel, and then to the distributor with the key on. Any decent ammt of resistance here .25 ohms or greater signals an issue in wiring or connectors, if all good move past this onto components and possible issues.

I personally think some component in the ignition is not happy, and it seems you are overdrawing the ignition honestly causing feedback. Also a good source of internally regulated coils are Standard Ignition. PN 1305. I use this coil for points systems frequently.

With your Petronix issues, resistor core wires or solid core? I know Petronix hates solid core wires. Id really look at this, and take a ohm reading of the spark plug wires. Too low of ohm also will cause overdraw on the ignition circuit failing in the way you have lined out.

 

I think it only notifies the first response, with an addendum that there may be more posts after this……

 

It never hurts to have a spare distributor around. Maybe some other brand?

 

You do know that when doing voltage drops measurements the circuit has to be on and working. If it is headlight, the lights have to be on; if it is the starter circuit, the starter has to be cranking. To check the ignition system it has to be live. I'd check it key on then check again key on, engine running.

 

The a/c plays havoc with the electronic ignition

 

I had a weird issue recently with a 1-wire alt. I also have a small cap HEI from DUI. Car was suddenly running like crap and quite bipolar. Saw Volt gauge drop to 10V then return to charging. Had recently tuned it as well (timing, carb).
After a bunch of dicking around I found out the alt rotor had failed. Dropped a new unit in and my timing was suddenly way off. So the bad alt was screwing with the hei.
Runs just fine now.
Any chance you got a buddy with a 1wire you could borrow?

 

I have had this issue in last few months,
Two different engines , & different types of Distributors, both MSD cap/rotor
1 ,3 or so months
The other 2 weeks 200 miles

 

I was being a smart ass. In your first post that I quoted you said "electrical" ignition, which even a points system is. I guess you didn't catch the sarcasm.

 

Yes, a

All voltage drop test done with the circuit live. At this point I'm going to have to start pulling the car apart even further and testing some different wires I guess

 

The alt has been checked twice, but at this point the season is pretty much over so I might just pull it off and have it gone through and checked again by someone else. Oddly enough, I don't know anyone with a spare 1-wire to try, lol

 

I did swap the cap outdoes to the hold down screw getting stripped since it's been in and out so many times these last couple months and it did make a difference, but it ohm'd the same as the old and could not see any damage(i.e. cracks or wear) but ultimately still have the issue. It was just an o'reillys or napa replacement.

 

Define check alt?

 

If the alt. shorted out at the terminal, it probably toasted a diode and it's allowing some AC to get through. Might be why the lights dim while cranking and would mess with ignition. Depending on the type of test procedure, it might not be found.

 

Alternator was taken to o'reillys and tested on their machine twice. At this point I will probably take it off and have it gone through completely.