plug lead glowing and smoking
#1
plug lead glowing and smoking
My Beauty 1988 V12 has had new leads, plugs, distributor cap etc fitted and has been running like a new car. Yesterday it scared the crap out of me when I was out of the car and my wife yelled that there was smoke coming from the engine. I opened the bonnet and one of the HT leads was glowing with smoke coming off it. I freaked out and grabbed my fire extinguisher which stopped it. I had not been running the car long enough for it to get really hot. After about 5 minutes I started the car and it was OK to drive a short way home.
HELP is it safe to drive - what could have been the cause? Could the lead have been arcing to something. Now when I look I can't even see which lead it was. Any help would be terrific and very much appreciated.
Les
HELP is it safe to drive - what could have been the cause? Could the lead have been arcing to something. Now when I look I can't even see which lead it was. Any help would be terrific and very much appreciated.
Les
#2
I can not see how a HT lead can get this hot and the engine remain running. The HT leads are also silicone insulated over 200°C rating. To get this hot the carbon conductor would have broken down and/or the coil fried.
I would look around and see if you can find another wire in the vicinity that has head damage.
I would look around and see if you can find another wire in the vicinity that has head damage.
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orangeblossom (09-04-2018)
#4
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Lesbrough (09-04-2018)
#5
#7
Current flow in a HT lead is on/off as the plugs fire, current enough to kill a HT lead would kill the coil first.
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#8
You're lucky it did not release ALL the smoke, we all know electronics/electrics work on smoke and when it's all gone it does not work any more................ Although in my experience these faults are much easier to find.
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89 Jacobra (09-08-2018)
#9
This is baffling. I have taken the car out and driven it until it’s “hotter than hell” and there is no problem. I climbed onto the (cold) engine and took a close look at everything. I can now only assume that there had been some foreign material blown in and landed on the hot wires and was cooked. It was between the coil and the Lucas ignition amp.
Is there something I am missing and it’s waiting to bite me again when least expected?
thanks everyone for helping, Les
Is there something I am missing and it’s waiting to bite me again when least expected?
thanks everyone for helping, Les
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Lesbrough (09-08-2018)
#11
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A couple or more thoughts:
1. Heat in a wire usually means high resistance. Or a dead short to ground.
2. If it was/is a wire either HT or otherwise, I would expect signs of damaged insulation, burnt or melted.
3. As the symptom is gone, and all seems well, I suspect foreign matter that cooked and the engine fans blew the ashes away.
4. Try the engine in the dark and see if you get a TESLA like light show. Evicdence of leaking insulation
Carl
1. Heat in a wire usually means high resistance. Or a dead short to ground.
2. If it was/is a wire either HT or otherwise, I would expect signs of damaged insulation, burnt or melted.
3. As the symptom is gone, and all seems well, I suspect foreign matter that cooked and the engine fans blew the ashes away.
4. Try the engine in the dark and see if you get a TESLA like light show. Evicdence of leaking insulation
Carl
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