Keep Frying HEI Coils PLEASE HELP!

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Backfoot100

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You don't remove the dizzy to R&R the ignition module.
I'm thinking that's exactly what the problem is. Thats the only other thing left.
 

AuroraGirl

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find an OE distributor on fleabay and use it(assuming its the same type/year range with different hookups) and use a used one. thats the only thing you need to verify. or bring to auto part store to test(if it can be)
 

AuroraGirl

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clean the distributor and see if you see any burns after a bit. a coil frying sounds like it cant ground. is the rotor turning properly? Is the rotor have plastic screws? is there play in shaft? is the bushing okay? how about thermal compound? Posts on cap dont have continuity to eachother? conductive buildup on components? seen it happen to a battery
 

Octane

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My coil was acting up and since the dizzy was 40 years old I checked the shaft freeplay and it was too badly worn to just do a coil.I put in a msd streetfire distributor,came complete and popped it in and for about the last 5 years it runs great.$175 at Summit.
 

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Just a shot in the dark but, where the coil is attached to ground is there paint (overspray) on it or is it rusty?
 

Poppy 87

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I haven't checked the ground straps between the engine to the frame. The ground strap I'm referring to is the ground strap that grounds the coil frame to the wiring harness. That ground prong has zero OHMS to both the engine block and firewall.
Slow down, do you realize Zero ohm indicate short? If you are measuring continuity there will be some measure of resistance. I don't like throwing parts at a concern, but make sure you understand what you are reading during diagnosis. Good luck
 

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Slow down, do you realize Zero ohm indicate short? If you are measuring continuity there will be some measure of resistance. I don't like throwing parts at a concern, but make sure you understand what you are reading during diagnosis. Good luck
?
I think 0ohms resistance means no resistance, or continuous.
 

HotRodPC

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Wihtout reading all your post and everyone elses responses, so if it sounds stupid to suggest, forgive me. What's your voltage output? Might have an issue with your voltage regulator and cooking them. How about any headlight or other bulb filaments? You going through any bulbs pretty quick too? You should want between 13.2 and 14.2 volts, Any higher and it's not good.
 

Poppy 87

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?
I think 0ohms resistance means no resistance, or continuous.
Perhaps using an analog meter, but a typical dvom when measure resistance will indicate : Ol=open circuit, .2,1,etc=continuity in ohms, or 0=short circuit. At which point you can determine if short to power or ground or internal fault

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bedwards

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I've read this thread over a couple times and maybe I missed it. Did you check and see if the coil ground wire is present inside the cap? There is a ground wire in there on top of the coil that hooks up to the wiring harness.
 

TyTexan

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Sorry. Been sick a couple of days and haven't felt human. Yes, Zero ohms means a short. I was testing between the ground strap (yes the one inside the cap to the plug). I was testing that to ground to make sure I had good ground. Yes, zero ohms, as in, indicating a good ground.

As far as voltage, it was a couple of days ago. But if I remember correctly, I was at like 14.3 volts with the old alternator (running at high idle). That seemed on the high side for me, so I removed it and took it to the store. I replaced the alternator with a new one and the guy at the parts store tested both the old and New alternators. Both tested fine, but the old one sounded funny. Like it sounded like a piece of sand or small particle was loose inside the alternator. So I replaced it anyway just to be on the safe side.

I've thought about this while I was sitting around feeling sorry for myself being sick and I've decided, there is only one wire going into that distributor and the plug wires coming out. The hot wire checks out with proper voltage and the wires leaving (plug wires and plugs) are all new. So there HAS to be something inside that distributor that is going out. Maybe a pickup coil, or control module, or some other kind of short. By the time I try and replace those, or any other parts, along with another coil, I am easily about $80. A new stock replacement MSD brand distributor is $177 with all new parts AND a warranty. So if it fries again, I just take it back. So tomorrow, I'll run to town and pick up the distributor, swap out and see what happens. I'll keep you guys updated. I appreciate the input.
 
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TyTexan

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Update. So I dropped in the new distributor. MSD brand street fire distributor. Its a OEM replacement by MsD. $196 out the door. 10 minutes later and its running great. Took a test drive and hauled a little hay. Ran great.

On a side note, when I pulled the old distrubutor, the coil was not actually melted this time. It looked good. Make me think that it was likely the control module going out and it finally went on the last time.

Anyway, its got a bunch of new parts and is running good for now.

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