Featured Technical New guy with odd electrical problem

Since the issue is loss of spark when run for a short while, I'd be looking at coil feed and return (grounds) like you already have.
The 200 degree coil is the indicator, but probably not the root cause.
Hope calling and talking to tech will get it sorted.

That voltage drop would be concerning in most cases, but I'm pretty sure you are just seeing the multimeter 'averaging' the voltage between coil circuit open and closed.

 

Got a response from pertronix. According to them, 200° is normal temperature for a coil while running give or take. Sent me a list of other tests to perform that was not on the website for troubleshooting. Said the voltage at the coil actually seemed low comparatively. Guess I will try these other tests this weekend and see what the results are.

 

Maybe a heavier gauge wire to feed the coil. What’s the voltage at the source of the wire that feeds the coil, before and after? Is the voltage drop through the key switch or after, through the wire?
Grasping at straws here but at this point who knows. I think Charlie found an old Mallory unilite distributor that I had in my Camaro that has a small cap and would fit, don’t know what shape the module is in, might be worth a try.

 

My first move would be check battery voltage at the coil when cranking.

 

https://www.davessmallbodyheis.com/

 

This is similar to what I have. External coil, old style cap.
https://www.ebay.com/itm/1963336013...FBE6MZ&hash=item2db665024a:g:0zIAAOSwgl9mkRf3

 

Rusty, if your up my way this weekend your welcome to stop by and check things out, just give me a call to make sure I'm around

 

Going to a swap meet in Florence with Charlie tomorrow so not heading into town.

 

[QUOTE="Basketcases, post: 15358405, member: 396592) Still haven't had a reply from pertronix about the input voltage to the coil but have re read the instructions saying to remove the resistor with their coil.[/QUOTE]

When I bought the Pertronix II over 10 years ago I asked about retaining the stock ballast resister. The tech replied you can keep it in if you want, the voltage to the plugs would just be lower. I had read when doing research on the that a few had coil problems so I left the resistor in the circuit. I have not had a failure. In fact I’ve never changed the spark plugs and they are clean when I check them once a year…

 

Try a ballast resistor.
A Mallory Unilite distributor is small. They have module problems too though. I have had one on a SBC for years with no problems.
Point distributor are small. Probably not what you want but it would eliminate the possible problem (Pertronix) and you would know for sure.

 

Well after emailing back and forth with pertronix they are out of ideas. Went through multiple tests they asked for going over grounds, resistance from the module back to battery, input voltage, and a few others. All numbers come back well within their range. Pretty much spot on normal. New edelbrock oil filled coil got about 200-220° with the car idling for about 20min and started dripping oil. Pertronix says oil filled does not run cooler. I am out of ideas. I am thinking if I put another distributor and coil in of any type, that the same will happen to the coil.

 

Here's another thought, now that every primary part and feed have been triple checked.
Something is making the coil work very hard. It gets hot, sure. But blowing up?
Check the secondary; rotor, cap center button, plugs, wires and especially the coil wire. If the ignition is working that hard and it's got good inputs, something is making it.

 

All the components listed were new when this started and ran fine for 350 miles. After the first issue, every part checked fine, then was replaced with another new part. Coil wire, cap, rotor, plug wires, plugs. All new but tested fine before they were replaced.

 

I agree that when you have a weird electrical problem, suspect a bad ground. You could try grounding the body and the engine to the battery with jumper cables and see what happens. If your engine is rubber mounted it can ground sometimes and fail to ground other times.

 

possibly why some run an earth strap from engine/transmission back to chassis.

 

OEM typically had the battery ground to the engine and a small ground strap from engine to body.

 

When it doesn't have spark, does it have power at the bat terminal of the coil?

 

I misread the title, I thought it said "Odd guy with new electrical problem" and thought to myself ... this guy will fit in here just fine

 

Does the car have a voltage gauge? If something was shorting out intermittently, it could cause the alternator to go to max voltage and possibly be over charging the coil and ignition. I know it all tests within range when you check it. But the car isn’t acting up at that time. Anything from plates in the battery bumping each other to a chafing wire can rub and create the over charging. If you had an amp meter that could handle the alternator full load that might tell the story as well.

Edit: to clarify I don’t mean the alternator has a short. Any short anywhere will increase the amp draw and cause a properly working alternator to go to max amp/voltage.

 

Electrical ignition?

 

Just some ideas

Try to connect coil and starter to a test battery and maybe connect battery to a charger to keep battery alive while testing.

Disconnect alternator etc just to see if the car will run / start without issues....


Are you running a single wire alternator?
Check these instructions out
https://static.speedwaymotors.com/pdf/91064022.pdf

Says to leave 4a off (page 5)

check ground cables, make sure lugs are not loose. (Should have grounds on engine, frame & battery)
Make sure all crimps are tight.

 

I also just read, that the car starts to die once the fan kicks on.

Can you try bypassing the relay and temperature switch and "hot wire" the fan directly to a 12volt source.

 

I have ran jumpers as a short term test, but added new grounds going from bat- to chassis and body, as well as body to engine and engine to chassis.

Yes, it still has voltage at the coil+ terminal. That is why I thought it was the coil failing.

Lol, that title would work as well. Still fits

 

The car does have a volt gauge but never shows a spike. Always reads 14.5-14.7 when running. 12ish when key on/engine off. When I had the cowl off, I tried moving all the wires around to see if I could cause the car to stumble or die. After multiple tries, I never could cause a problem. Battery is new again so this issue has happened with 2 new batteries. I don't have an amp clamp to put on the car while running to test the draw, but that might be in the near future.

I have ran the car with the alternator disconnected with the same results. It is a 1-wire alternator, we have looked at those instructions a lot. The car ran fine for 350 miles. Then had the sudden issue. I will definitely be going over all of the harness instructions again next time I have the cowl off the car. I don't believe the car died when the fan tried to turn on. If I wrote that, I apologize. I was letting the car run and was going to shut it off when the fan turned on just to let it go thru a warm up cycle. Fan turns on at 185° on the dot, I was watching the temp gauge and it passed 180 and before I could walk to the front to see when the fan was going to kick on, the car died. I did find a problem with the inline fuse holder to the fan relay. This caused the fan itself not to turn on and has since been fixed. Since then, the fan has cycled multiple time with the car running

 

If you have voltage available to the coil and no spark, your problem is either the coil or what activates the coil. Since you have changed the coil, I'd be looking at the distributor electronics as you said it is a Pertronix or the wiring to the distributor. I know they have told you everything checks okay, but if you don't have spark with a good coil, the problem is in the distributor.

 

I agree... I'll throw out one more thing to check. Pertronix modules have two wires; one is 12V power in, the other is the ground out to the coil. The other 'end' of the ground wire is gotten through the distributor body/motor. I'd test it like this: run the car until it stops if you can. Then disconnect the ground wire from the Pertronix at the coil and remove the distributor cap/rotor. Turn the motor by hand with the ignition 'on' until the Pertronix unit 'closes' which you check by looking for continuity with an Ohmmeter between the coil connection and metal ground inside the distributor. This won't hurt the module as there's no load on it. Look at your Ohms value; it should be near zero (.1 Ohm or less). Also check at the engine block and negative battery terminal to see if it stays at a low value. Paint/powdercoat can interfere with the ground path.

You also don't mention what type of distributor you have. If it has vacuum advance (or had it but is now locked out), there should be a ground strap between the point plate and the distributor body, make sure that is in place.

A too-high resistance in the coil ground path will cause the coil to pull more current and cause the issues you're having.

 

This is the third module in the distributor. First one definitely went bad for some reason but ran fine the first 350miles, think the second was a return to the store and bad out of the box. Now this one fires and will run but now have the other issues. I have moved the wiring around while the car is running trying to cause an issue but can't make it happen. Connections are tight and have been checked. I agree, if I have power or spark up to a certain component and nothing after, that component should be the problem. That is now why the entire ignition system has been replaced. I would find a bad part, replace it, get spark/power for a short time, then nothing again, check the part I just replaced and it's fine, move to the next component, test bad, replace, work short term, fail then test fine, move down to the next part, and repeat. Hope that makes sense. Haha

Crazy Steve, that is one of the tests they had me perform though I can't do it after running the car till it stops. The distributor is tucked in the firewall behind the carb and blower and can't get tools or hands on it unless you remove the fuel line, linkage, and carb. Even then it's tight. Reading from the ground plate holding the module in the distributor to the negative battery terminal showed 0.1-0.0 ohms. Pertronix specs said anything 0.2 or less is fine. Distributor was a new replacent(not rebuilt/reman) fro. O'reillys. Initially it had the timing locked out but found an issue with that while going thru all this and has since been unlocked for vacuum advance. Even though the reading is fine, we were already talking about pulling the dist and making sure the wire you're talking about is connected. Unfortunately, to do that, the blower may have to come off again as well.

 

I'd still do this check off the wire to the coil coming out of the module. You're not checking the ground path through the module, I'd want to know that's good also. And keep in mind that when the point plate moves while driving, the ground resistance could be changing also if that bonding wire is missing. And if you're running a big spark gap, I'd close that down to .032-.035" to reduce stress on the coil.

This one is a real puzzler....

 

Quick question, I am late to the game here.

What gauge is your wires from the battery to the starter and ground? And also what gauge wire from the battery feeds your fuse panel. and How long are such wires?

I have found on 6 volt cars, that the normal wire gauge you buy at the store is too small, and if you have a motor with some ass the wires are too small for 12v also. Sometimes a supply wire being too small causes a bottle neck etc.

Also terminal ends for battery cables are notorious for being badly crimped etc. or having corrosion inside.

Just a few points to ponder. Saying you are eating batteries it sounds you have a big amp problem.

 

This really is a problem you want to hit with "modern" technology, in the form of a oscilloscope; a mobile, battery powered, 4-channel one with a lot of memory. You would hook it to ignition system positive, negative and the line between coil and electronics, and have a spare channel to monitor whatever you like, perhaps the coil current using a current clamp or ignition secondary if you have the probe for that.
Anyway. What you get is a recording of exactly what happens first, you can see what happens ~microsecond by microsecond (depending on settings, available memory and the total length of the recording, a spark lasts about 1/1000th of a second so that's VERY detailed data, a thousand datapoints just during one spark). You see if you lose power, ground, or the electronics simply stop switching the coil current first. Cold, hard evidence pointing towards the cause.

A more common, cheaper 2-channel scope can do the same, but can only monitor two things at a time = you need to record more than one occasion to get all interesting places checked.