I've just recently restomoded my Dart, and all of a sudden smoke started coming out from under the dash. Turns out the two hot wires that go to the amp gauge decided to go mission impossible on me. Melted the plastic off the wire not to mention what it did to my bulkhead connector box. I'm running an MSD6 with a MP Electronic Distributor. I've also updated the system to the later electronic voltage regulator. The first problem I had was that the car would turn over, but not start with the key. I had to install a start button wired to the starter relay to get it to fire up. Now the wires got hot and melted. The underhood harness is all new. I figured maybe the bulkhead box was putting up to much resistance causing the wiring to get hot. So I wired the two seperately through the bulkhead with no connections, 10 gauge wire, and soldered the lines together. Fired up the car, and at first that seemed to solve the problem. Then while the car was running and under the dash I reved up the engine to about 2k rpm's and the wires starting getting very hot again. So I broke out the multimeter and started checking loads on the battery, altenator both at idle and acceleration. I was showing 12.6 at idle, and roughly 13.7 at around 2k rpm's. Well all that seems just about where it needs to be for a typical charging system. I haven't been able to check the load yet on the two wires running to the amp gauge, but obviously somehow they are being overcharged to the point the wires want to melt. I'm taking the altenator to a shop tomorrow to be tested to see if it has any issues, and maybe pick up another voltage regulator to see if maybe the new one that is in the car has somehow gone bad, but it doesn't made sense that the battery is seeming to get the correct charge both at idle and revving the engine. Anyone had this type of problem before and what solution did you come up with? I followed the wiring instructions to the "T" and have gone over my wiring three times just to make sure I didn't miss something. So any help with the hot wire issue, and the not being able to start with the key would be appreciated. One other note is that all the parts that are in the car currently are brand new parts. Everything is new, so I'm left scratching my head on this one guys. Please help...

you're old enough to remember mission impossible . Smoking wires: Either too much flow (amperage) from overcharging or a dead short or a bad connection (or a combination of both). If the batt is up to where it is not overcharging & 13.7 sure sounds OK. I would put one of the large ammeter wires on the other side (both wires on same side on the same terminal) to bypass the ammeter & try it. EDIT I'm assuming that the yellow wire to the "sol" terminal on the starter relay is not getting fire in "crank"? Trace it back upstream to the bulkhead terminals (on both sides) for it then under the dash trace it further rearward to the ign sw (st) terminal. And that the "grn" terminal on the starter relay is grounded thru the NSS or bypassed.

Wow.

You have several problems all once. I would address them 1 at a time.

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I've just recently restomoded my Dart, and all of a sudden smoke started coming out from under the dash. Turns out the two hot wires that go to the amp gauge decided to go mission impossible on me. Melted the plastic off the wire not to mention what it did to my bulkhead connector box.

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This sounds to me like the Ammeter is shorting out. IT could be a bad ammeter or more than likely the insulators (usually a thick paper like material) are bad. In either case do not connect the ammeter until you verify it isn't shorting because any gauge wire will burn if there is a direct short involved.

Check the fusible link. Usually if you smoke an ammeter wire it will toast the fusible link also.

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The first problem I had was that the car would turn over, but not start with the key. I had to install a start button wired to the starter relay to get it to fire up.

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You need to find out the problem here. It could be several things, wiring, ignition switch, or ballast resistor. Laying odds on this one it is a bad ballast resistor or connection at the bulkhead. Still check for voltage at the crank position of the ignition switch.

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Now the wires got hot and melted. The underhood harness is all new. I figured maybe the bulkhead box was putting up to much resistance causing the wiring to get hot.

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The heat should be at the point of resistance not in the wires. Resistance causes heat (think of a light bulb) too much CURRENT causes the wires to overheat. Your problem is either the wires are too small or their is a heavy load/short circuit if the wires are heating up.

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So I wired the two seperately through the bulkhead with no connections, 10 gauge wire, and soldered the lines together.

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10 gauge is the minimum I would run. 8 gauge would be better.

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Fired up the car, and at first that seemed to solve the problem. Then while the car was running and under the dash I reved up the engine to about 2k rpm's and the wires starting getting very hot again. So I broke out the multimeter and started checking loads on the battery, altenator both at idle and acceleration. I was showing 12.6 at idle, and roughly 13.7 at around 2k rpm's. Well all that seems just about where it needs to be for a typical charging system. I haven't been able to check the load yet on the two wires running to the amp gauge, but obviously somehow they are being overcharged to the point the wires want to melt.

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I do not think your problem is overcharging. I think your ammeter is shorting. I would bypass it. My opinion but I would bypass it and recheck.

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I'm taking the altenator to a shop tomorrow to be tested to see if it has any issues, and maybe pick up another voltage regulator to see if maybe the new one that is in the car has somehow gone bad, but it doesn't made sense that the battery is seeming to get the correct charge both at idle and revving the engine. Anyone had this type of problem before and what solution did you come up with? I followed the wiring instructions to the "T" and have gone over my wiring three times just to make sure I didn't miss something. So any help with the hot wire issue, and the not being able to start with the key would be appreciated. One other note is that all the parts that are in the car currently are brand new parts. Everything is new, so I'm left scratching my head on this one guys. Please help...

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Before you do anything else make sure you have a good fusible link and that is actually a fusible link. Not just a piece of regular wire. If you are popping fusible links then I would suggest you put in a 30 to 60 amp circuit breaker in temporarily while you diagnose the problem. Circuit breakers will reset and you can keep testing. Do not use one for driving they could at any time trip leaving your car to stall out. But for diagnostics they are OK.

I hope it helps.

I've allready bypassed the ampmeter, and since I'm running the MSD it doesn't require that you run it through a ballast resistor so that isn't hooked up either. Altenator checked out ok today, so now I'm leaning toward the voltage regulator. As far as resistance is concerned I bypassed the two hot leads out of the bulkhead connector and ran them strait into the firewall. I made the connections under the dash by twisting the wires, and soldering the connections. Finished it off with heat shrink tubing so that I could eliminate any chance of resistance. I'm not blowing the fusible link though. I've chased out all the lines under the dash looking for a short, exposed connection, loose connection, etc... in the hot branches that feed the ignition swith, fuse box, etc... I'm not seeing anything. So this leads me back to thinking that this is a voltage regulator issue. So even though things appear to be reading normally at idle, there has got to be a reason why those wires get hot when revving the engine above idle. I was just hoping that someone on here has ran into this same problem and could pass along the fix. But all input and suggestions are welcomed. Thanks guys, and gals.

I think you will find your answer here. http://www.madelectrical.com/electricaltech/amp-gauges.shtml

That is an excellent post, and link. Explains alot of what I have been wondering. I think I will be able to solve my issues with this as a guide. Thanks very much.

When did the wires smoke?
When the battery was connected, or only after the ignition key was turned on?
The only way I think the wires would smoke without blowing the fuseable link is if the alternator is running and supplying the current to the shorted circuit? There could be a short in the ignition switch, wiring to the fusebox, or the undehood power (alternator field, regulator, Ignition box, or electric choke?)

I would start by checking the alternator brushes and holders to make sure they are not dammaged or melted causing intermittent shorting.