fried coil

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73dartswngr

73dartswngr

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I have a 73 swinger w/318, I have went through three coils in less than a year. They go with no real way of knowing it just happens, is their a reason why. It is an aftermarket oem type coil, nothing fancy, just lifetime warranty. any suggestions would be great.:banghead:
 
It seems to have other problems and not just the coil. I would go through the system and check the grounds..
 
How do you know the old coils are bad? I expect you will say "changed it and problem went away", but that is hardly definitive. Why? Changing it could wiggle a wire and fix a bad connection, etc. If a factory coil isn't overheating, it will last for a very long time. If it overheats, it will be too hot to touch and you will smell paint burning, but when it cools it will probably still work. How would I know? I jumpered +12 V straight to coil+ once to drive a newly bought A-body home, got 5 miles and started missing above 40 mph, coil was very hot, wired thru ballast and no more problems.
 
1...........What are you buying for coils? Brand? Exact part number?

2...........What are you running for an ignition, IE points? Mopar ECU? Other?

3...........Ballast resistor?

4...........Have you done anything towards voltage measurements on the coil and resistor, and system running voltage at the battery? Any trouble with the battery boiling over?

5..........Have you checked for coil heating, IE run it awhile and felt the coil?

6...........Do you or anyone routinely leave the key in the "run" position with the engine "not" running?

These, and many other questions.........................


To put things in perspective.............I've junked out a couple of cars, one was a 77 Dodge van, and I do not believe the regulator, the ECU or the coil have ever been replaced. I would bet money that the ballast had not, either. In my lifetime, on my own cars, I bet I've only needed to replace a couple of coils. (I'm 65 years old) I have had to replace a couple of ECUs and a couple of ballast resistors or maybe more. At least one or two ballasts may have been damaged by cold (winter) splash.
 
There are a few reasons why a 73 would just die suddenly. When its intermittent temperature related failure in the ignition, the time it takes to R&R a coil or most anything else would allow the true culprit to cool and function again.
When its a hidden charging system issue, It likely only fails when heat, wipers, headlights, etc.., are all on.
 
alright to clear it up for everyone, the coil is being replaced, I have got the new oem type coil from shucks/oreilys so its probably not the best but its in my price range (and since it keeps going out and has lifetime warranty its really in my range) I don't have the exact part number handy. the car has electronic ignition I believe since its a 73 so I don't think points are an issue. the reason I know its the coil is because as soon as I replace it, the car fires right back up again. so now if anyone has any suggestions then I will be all ears.
 
73dartswngr said:
so now if anyone has any suggestions then I will be all ears.
Click to expand...

Yeh I do. How about answering the questions I asked you, please?. I don't type this stuff out to hear my keyboard rattle.


67Dart273 said:
3...........Ballast resistor?

4...........Have you done anything towards voltage measurements on the coil and resistor, and system running voltage at the battery? Any trouble with the battery boiling over?

5..........Have you checked for coil heating, IE run it awhile and felt the coil?

6...........Do you or anyone routinely leave the key in the "run" position with the engine "not" running?

.
Click to expand...

Quite frankly, if you are returning to the same parts store time after time, buying the same type coil, I'd try "somewhere else," and maybe invest a little more money in a higher quality coil. That might not be the trouble, but with so much trouble, it would be worth a try.
 
I have not checked the ballast, and guess this is why I am asking for suggestions on what to start with. what voltage or ohm am I looking for their. also what voltage should I have at the coil, battery or less? I would love some feedback on that so I could possibly figure out why the coil is going bad.
 
The coil + voltage will vary. Battery should run not more than 14.5 running at a fast idle

Coil might be anywhere from 9-12. If it's more than that, you've got trouble
 
You need to have a voltmeter to run this down. It think you should continue to address this because it indicates something is wrong, which could lead to worse....

Measure as above; measure right on the coil + with the meter, and with the meter - lead to the alternator case (on a clean spot so you have good contact) or the battery -; the reading might be a bit different with the car running vs just having the ignition switch in the 'on' position. That coil + voltage might vary from the above range a bit, but not by much.

I too would like to hear the answers to Del's original set of questions; they are important to know to be able to help further.

And BTW, if you get/have a cheapo meter, check the battery after the car ahs run and then set overnight to see ifg you get around 16.6v on the battery. Crosscheck it on another car too, in case your car's battery is weak or something is not charging. Adn you can chekc it on a 9V battery, and you should read around 9.6v on a new one. All this is necesary to make sure your meter is accurate. I check my $15 and $200 meters regularly this way to make sure they are still accurate.

Do you have the wiring diagram for the car? That'll help other to help you.
 
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