Slant Six Forum :: Burnt out HEI ignition coil?

It sounds like you have a defect somewhere for sure. I would want to see a schematic of how you wired things before making any pronouncements.

The negative side of the coil should be the only thing on the C terminal of the HEI module. Is that true or do you have a tachometer?

I can't make sense of your pictures. Draw a diagram. It's good for troubleshooting. You will probably want to have your car's wiring diagram available.

If you grounded the negative side of the coil then it was you who destroyed the coil. Draw a diagram of the circuit you made and you'll see why.

The wires that went to the ballast resistor are connected together so that the HEI system gets full voltage all the time.

This does not need to be so complicated. Why are there 2 relays? Why is the starter and voltage regulator wiring highlighted? All you need from the original wiring is switched battery voltage to the HEI module and coil. You get that by bypassing the ballast resistor. If you have low voltage at the coil and ignition module then consider a relay triggered by the coil feed.

It looks like 14 yellow to coil and module not getting power during cranking. Relay working off run circuit

Author:	Hilderbrand1983 [ Fri May 22, 2020 3:48 am ]
Post subject:	Burnt out HEI ignition coil?
'67 Dart 270, wired in an HEI ignition per this forum. Used a Standard FD478 ignition coil. I can't get the darn thing to start but it cranks just fine. That is, until yesterday. I think I resolved the no-spark condition in the startup ... only to have the ignition coil nearly catch fire. I removed it from the car immediately and it was hot to the touch for ~30 minutes or so. Part of the plastic guts poured out like lava from the front. Have I done something horribly wrong? BTW, melting Ford ignition coils smell sweet, like candy!

Author:	Joshie225 [ Fri May 22, 2020 8:22 am ]
Post subject:	Re: Burnt out HEI ignition coil?
It sounds like you have a defect somewhere for sure. I would want to see a schematic of how you wired things before making any pronouncements. The negative side of the coil should be the only thing on the C terminal of the HEI module. Is that true or do you have a tachometer?

Author:	Hilderbrand1983 [ Fri May 22, 2020 9:55 am ]
Post subject:	Re: Burnt out HEI ignition coil?
Quote: It sounds like you have a defect somewhere for sure. I would want to see a schematic of how you wired things before making any pronouncements. The negative side of the coil should be the only thing on the C terminal of the HEI module. Is that true or do you have a tachometer? Thanks for this. I'll see if I can upload some pics to imgur to post on this forum. This simple upgrade has been full of gremlins. I think I may have screwed up where the instructions read re: the ballast resistor wires, "plug them into each other." I did that as if they were running across the ballast resistor. Was that wrong? Also, the ignition coil very helpfully does not indicate which is the positive connector. I assume the notched connector is the negative one. The lead I bought on Amazon (recommended in the instructions) only snaps on in one direction, so I also assume the ignition coil is "keyed" in that direction (that is, I am simply unable to plug it in backwards). I'm about ready to throw this whole thing in a river and go find my old points distributor.

Author:	Hilderbrand1983 [ Fri May 22, 2020 10:01 am ]
Post subject:	Re: Burnt out HEI ignition coil?
Here's a link to the imgur album - https://imgur.com/a/SSHJlNB I've got two red wires on the relay next to the coil, but that's temporary (I only had red of the proper gauge laying around). The 30 post (which gets full power) is a red wire as well. Also, I have a tach lead but no tach (I attached a ring terminal in an attempt to ground it, hoping that would solve my problem. No luck). I'm happy to answer whatever questions you might have so you can get a better idea of the problem I've created - crank, no spark.

Author:	Joshie225 [ Fri May 22, 2020 10:02 am ]
Post subject:	Re: Burnt out HEI ignition coil?
I can't make sense of your pictures. Draw a diagram. It's good for troubleshooting. You will probably want to have your car's wiring diagram available. If you grounded the negative side of the coil then it was you who destroyed the coil. Draw a diagram of the circuit you made and you'll see why. The wires that went to the ballast resistor are connected together so that the HEI system gets full voltage all the time.

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Author:	Hilderbrand1983 [ Sat May 23, 2020 6:38 am ]
Post subject:	Re: Burnt out HEI ignition coil?
Quote: I can't make sense of your pictures. Draw a diagram. It's good for troubleshooting. You will probably want to have your car's wiring diagram available. If you grounded the negative side of the coil then it was you who destroyed the coil. Draw a diagram of the circuit you made and you'll see why. The wires that went to the ballast resistor are connected together so that the HEI system gets full voltage all the time. Ok, so here is the original wiring diagram (I've highlighted the relevant wires) and a diagram I made with Word of how things currently look under-hood:

Author:	Badvert65 [ Sat May 23, 2020 9:00 am ]
Post subject:	Re: Burnt out HEI ignition coil?
Attached are two of the most basic HEI diagrams. One with a relay, one without. Either way, the "Ignition Switch" signal is the "Start/Run" from the OE vehicle wiring. Attachment: HEI-Diag.JPG [ 47.2 KiB \| Viewed 5472 times ] Attachment: 1-GM-HEI-opt.jpg [ 25.02 KiB \| Viewed 5472 times ]

Author:	Badvert65 [ Sat May 23, 2020 9:15 am ]
Post subject:	Re: Burnt out HEI ignition coil?
FYI, Your wiring diagram looks like it is correct. Maybe you should check to see if you have any wires accidently grounded, especially to the coil.

Author:	Joshie225 [ Sat May 23, 2020 10:18 am ]
Post subject:	Re: Burnt out HEI ignition coil?
This does not need to be so complicated. Why are there 2 relays? Why is the starter and voltage regulator wiring highlighted? All you need from the original wiring is switched battery voltage to the HEI module and coil. You get that by bypassing the ballast resistor. If you have low voltage at the coil and ignition module then consider a relay triggered by the coil feed.

Author:	Hilderbrand1983 [ Sat May 23, 2020 11:11 am ]
Post subject:	Re: Burnt out HEI ignition coil?
Quote: This does not need to be so complicated. Why are there 2 relays? Why is the starter and voltage regulator wiring highlighted? All you need from the original wiring is switched battery voltage to the HEI module and coil. You get that by bypassing the ballast resistor. If you have low voltage at the coil and ignition module then consider a relay triggered by the coil feed. One relay is for the voltage regulator, the other is for the module. I put the VR-128 into the diagram because some wires that formerly went to the ballast resistor now run through that relay to the voltage regulator. And I don't know why this is so complicated but agree, it does not need to be such.

Author:	Joshie225 [ Sat May 23, 2020 3:45 pm ]
Post subject:	Re: Burnt out HEI ignition coil?
Draw a schematic diagram showing the ignition circuit. You have created a wire-run diagram. That's fine for showing how to put something together, but it's not very good for showing how something works. Take "firewall" out of the diagram. Add the ignition switch. Delete the ground wires, but show the grounds. Why is the coil bracket grounded? You don't need that. The voltage regulator should not be drawing power during cranking so its relay should be triggered on only in the IGN1 (run) condition.

Author:	matv91 [ Sat May 23, 2020 5:08 pm ]
Post subject:	Re: Burnt out HEI ignition coil?
It looks like 14 yellow to coil and module not getting power during cranking. Relay working off run circuit

Author:	Hilderbrand1983 [ Sat May 23, 2020 5:20 pm ]
Post subject:	Re: Burnt out HEI ignition coil?
I swear, I'm just about ready to give up. Took the relay out of the equation altogether by wiring my 16DBL* wire from the ignition straight to the module. I know it's not good for the module (I've got two extras) but maybe it was a bad relay. Really grasping at straws here. Nope. Still no start. With the key at RUN, the B and C posts on the module have power and the W and G posts are grounded. If the new ignition switch doesn't fix it, I'll be totally out of ideas.

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