Bad Ingnition Wire to Coil?
I have recently worked with an experienced mechanic to rebuild 427/390HP in a 1969 coupe. For looks and protection I also installed a new set of wire braded plug wires. During the start up we think one of the plug wires was in contact with the positive post of the coil while the key switch was in the on position. A short time later we saw/smelled smoke and think we damaged the ignition wire to coil. First question is this wire a resistive wire? We have since run a new wire a resistor to the coil and the car starts/runs good but the smell remains. Can anyone tell be where/how the ignition wire to the coil gets its power?
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Re: Bad Ingnition Wire to Coil?
The first bit of bad news is that the ballast resistor was not used after 1967, the second is that the failure mode from the problem you described is that the resisatance wire heats to a level that will melt the insulation of the surrounding bundle, causing shorts, very likely why you are still smelling wiring burning. If you have not disconnected the battery, do so IMMEDIATELY, and from there you will have to remove the wiring harness and unbtape it to inspect for damage and make a decision to replace/repair, Unfortunately, I would recommend checking the IP wiring also for damage and potential replacement...Bill Clupper #618 -
Re: Bad Ingnition Wire to Coil?
Should I just be concerned with the ignition harness or others as well? Also just check the wires that go to the fuse block? Would rather have the bad news now rather than be stuck on the side of the road or have an electrical fire....Comment
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Re: Bad Ingnition Wire to Coil?
Shawn,
The IP (Instrument Panel) wiring that bill suggested checking is the wiring harness inside the car from the fuse box to the ignition switch, and possibly up to the instruments. Corvettes have burned to the ground from these kinds of problems -- thus the reason Bill suggested disconnecting the battery IMMEDIATELY. The only way to know the condition of the wires is to unwrap the harness, separate, and examine them. The condition of the wires will tell you how far you need to go up the harness to feel safe. There is no way we can tell that over the Internet -- it just doesn't work that way. It is a lot of hard work, but shortcuts in this area can be very dangerous.TerryComment
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Re: Bad Ingnition Wire to Coil?
Should I replace the IP harness and ignition harness?Comment
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Re: Bad Ingnition Wire to Coil?
My Internet crystal ball isn't working today.
You will have to look at the wires to see if they are damaged, and also make an assesment of the over-all condition of the harness -- have there been splices or modifications to the wiring over the last 40+ years? -- in order to decide the wisest course of action.TerryComment
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Re: Bad Ingnition Wire to Coil?
The car has spend most of its life in the South Dakota, only has 47k miles, and is always garaged. Most of the wires look to be in very good shape and with minimal if any splices. Frustrating that this happened in the first place but basis past threads it appears shorting the resistive wire has happened to others. I am going to start with the ignition harness first and go from there. However I certainly appreciate the heads up regarding the Dash/IP harness and will take a close look. I think your crystal ball is working just fine.Comment
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Re: Bad Ingnition Wire to Coil?
Shawn,
The price you'd pay to swap out a questionable harness would pale in comparison to a car fire. Regardless of the mileage or being garaged, in the end it's a 46 year old electrical harness. It's cheap insurance.Comment
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Re: Bad Ingnition Wire to Coil?
I had to make a few phone calls and ask a few questions regarding which harness I needed to get but have ordered a new harness. Would still like to know where the resistive ignition wire gets its power source from.....Comment
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Re: Bad Ingnition Wire to Coil?
Ignition switch, it is paralleled in the harness with a wire from the solenoid that is energized when the starter is engaged to supply 12 volts for cranking then switches off to allow the resistive feed from the ignition to keep the car running.Bill Clupper #618Comment
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Re: Bad Ingnition Wire to Coil?
Did a continuity test and found problems with both the engine harness and dash/IP harness. Going to replace both. I really appreciate the help and suggestion to test both or I could have ended up watching the car go up in smoke. Not looking forward to the work but as Mike and others commented it is cheap insurance.Comment
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