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Old 08-01-2017, 12:09 AM   #1
Foot Stomper
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55 Cameo letting the smoke out of wiring. Help really needed.

Here's my report of what happened tonight (as best as I can recall).

I accidently left ignition on (after moving the truck outside) to adjust shifter linkage under hood while the Mrs worked the shift lever, and after about 20 minutes of linkage fiddling, the green wire from ignition to positive terminal on coil smoked and burnt to a crisp! In a panic I turned off ign switch and disconnected the battery cable. I then replaced crispy wire with new green 18 ga wire. The terminal block on ignition switch that connects green 20 ga wire also feeds a green 20 ga wire to resistor on firewall.

Just before the linkage tinkering, I did rearrange the green positive coil wire under hood by pushing some of it's excess wire through the grommet in firewall towards the interior of the truck. I mention this as I am not sure this contributes to the challenge or not...

Tried starting (no start), this time green wire to resistor let the smoke out. I turned off ignition switch and disconnected battery cable... in a panic!

I took a jumper wire from pos terminal on coil to battery and tried starting but it failed to fire. One thing this truck did before tonight was fire up immediately without hesitation or coaxing.

Keeping in mind that an attempt to hotwire the truck without a successful start, I changed ignition switch with another one - untested but seemed to be in working condition. Tried starting (no start). NOTE: The replaced switch had a "start" function (and a small bulb and socket) which varied from the wiring diagram and the replacement I had in my spare parts bin.

Jumped resistor brown to green and then the violet wire from solenoid to ignition switch let the smoke out!

This a new truck for me. I have removed many wires that were installed for trailer brakes and other things not factory related. Replaced the cracked coil with a new one, cleaned everything up nicely, wired turn signals and until now, I was 100% happy with the overall condition of the wiring. The general condition of the wiring is old, but very good. The wiring diagram matches 99% to the truck's wiring; the green wire (coil pos to ign) had a pink butt connector but aside from that and a different colored wire to the neg post on coil to distributor, all other wires and connections are factory.

I have had the truck running for over an hour since I brought it home a month ago. I have been working to get it road worthy and in doing so, rebuilt the carb, replaced all coolant hoses and coolant including the water pump.... this is to say that I have had no smoked wires to date while starting it and letting it run to get up to temperature and getting the signal, brake and dunning lights working.

I put in a 25 amp inline fuse to power the turn signals and it is still good after all the smoked wires. One thing that was fried when I got it was that power supply wire to signals and once I cleaned up all the tail light wiring by replacing it with all new,

I am very confused and upset that what was once working perfectly is now burning up wires and it seems to be getting worse instead of better.

I wonder if my new coil is the culprit for these newly smoked wires?

What's a damage report without pictures...
First one is green from ign to coil.
Second is violet.
A picture of green wire with butt connector before it melted.
A picture or my ignition switch that was in the truck, before I removed it.

Thanks guys... I hope one of you can help figure this one out for me.
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Old 08-01-2017, 12:35 AM   #2
VetteVet
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Re: 55 Cameo letting the smoke out of wiring. Help really needed.

Sounds like the coil or the resistor is shorted to ground. When you turned the key on and left it on for 20 minutes you may have shorted the coil.
When the key was turned to start (purple wire) the hot red wire and the shorted green wire
connected with the purple wire and shorted it to ground causing the smoke.

When you hot wired the burned up coil it should have caused the hot wire to smoke unless the coil windings were burnt in two, which would explain the no start.

Are you running your wiring through an amp meter or to a battery gauge?
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Old 08-01-2017, 12:52 AM   #3
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Re: 55 Cameo letting the smoke out of wiring. Help really needed.

I am running the truck wiring through the amp gauge.

So, replace the coil and burnt wires as they are currently wired and all should be good again?

The hotwire attempt caused no heat or smoke in the 14 ga hot wire jumper.

Thanks for your help VetteVet!! I'm near panic here and your advise is very helpful!
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Old 08-01-2017, 09:51 AM   #4
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Re: 55 Cameo letting the smoke out of wiring. Help really needed.

Assuming you have a points distributor, you should check the points for burning or welded together. You should also check the green wires for short to ground before you put voltage to the new wires.

It would also be a good idea to pull the wires off the coil terminals and check between them for resistance. The meter should read just under 3 ohms. If you get zero ohms the coil is shorted out and if you get infinity or no reading then the coil wiring has burnt and this is probably why it won't spark.
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Old 08-01-2017, 05:27 PM   #5
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Re: 55 Cameo letting the smoke out of wiring. Help really needed.

Today I replaced four wires with new ones and replaced the coil.

No more smoke and wiring stayed cool to the touch. Phew!!

Thanks VetteVet for helping me through this nightmare of nearly burning my truck to the ground!

I bench tested the fried coil and had no connectivity at all.

The points seemed to look OK before I tried starting it. I started it and it ran very poorly. Seemed only 3 of 6 cylinders were firing. I am going to replace the points and condenser tomorrow. I reinspectrd them and they did look discoloured.

Hopefully that will be the end of this chapter.
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Old 08-01-2017, 07:19 PM   #6
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Re: 55 Cameo letting the smoke out of wiring. Help really needed.

http://www.ebay.com/itm/CHEVY-INLINE...item4d5f189877
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Old 08-03-2017, 12:20 AM   #7
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Re: 55 Cameo letting the smoke out of wiring. Help really needed.

Well, I replaced the points and condenser and still has a miss. Running on 5 cylinders sucks! Especially when it ran perfectly before the smoke!
Changing cap, rotor and plugs tomorrow. Hopefully this is the final, final chapter!
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Old 08-04-2017, 08:17 PM   #8
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Re: 55 Cameo letting the smoke out of wiring. Help really needed.

Turns out it was spark plug on cylinder one. As soon as I changed it out, smooooth idling.
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