86 2.9l wiring issue almost caused fire

[Cameron1591]

Sorry in advance for the novel, but theres a lot that could comtribute to my problem. So I'll start out with the problems I know I've had in the past.
Shortly after buying the truck last year I replaced the heads due to milky oil.
Got all the work done there, and it ran fine for weeks. I had jnstalled a larger used radiator, new cap and rotor, new platinum 4 plugs, new wire set, and new battery with the heads.

Then I noticed a new problem one night that was not an issue b4.
When I turn on my brights the engine would drag down drastically and almost die. Turn them off and it's back to normal.

About 2 weeks after this started my ignition coil "went out".
It had a large crack on the bottom and had stalled out at 30mph. It started smoking when I tried to restart and that's how I found it was the problem. It partially melted the plastic of the wire harness when this happened.
I replaced it and it started right up.

9 days later the same new part went out. Somehow power steering fluid got on it and may have caused it to short. Still unsure how this happened.
Replaced it and drove for about 2 weeks.

Made a turn one day and the engine died almost instantly when I put my signal on. Tried to restart 3 times and it wouldn't take. On the 3rd try smoke started pouring out of the hood.
I popped the hood to see a wire smoldering by the "remote power terminal" behind the battery on the passenger fender. Also saw a wire smoldering on the driver side fender.
Quickly disconnected the ignition coil wire harness and rotor cable. It quickly stopped smoking.
The 2 wires look like they may be the same wire running from terminal across the grill back into the firewall. The section by the terminal peeled the insulation off and the driver side section burnt apart comletely.

Haven't had time to trace wires or look into it much.
The battery still had a full charge about 5 weeks later.

Any ideas of what my problem could be? I have a few just looking for more experienced input.
Any advice is much appreciated.

This isn't my daily driver so it's not an urgent issue for me. Was unsure what forum to post it in though.

 

[RonD]

I would first check all the fuses, someone make have used the old "penny trick" instead of a proper fuse.

The 1986 may have two wires to the "+" on the coil.
1 wire is from the ignition, key switch, this will have a ballast resistor, so coil only get 8volts when engine is running, this prevents coil from burning out.
the other wire is from the starter motor solenoid, this gives the coil 12volts, but ONLY when engine is cranking, this helps for cold starts.
This wire might have been moved to the battery side of the solenoid, which can cause the early demise of coils.

Melted wire means a 12volt wire was shorted to ground but without a fuse, or fuse would blow before wire could melt.
The alternator's B+ hookup should have fusible links, short wires that will burn out if there is a short, these often go on the starter solenoid, battery side.
Alternators can fail and send out higher voltages, up to 50volts, which would melt wires if alternator's B+ wire(s) was not fused.

Other wires you will just have to trace and see why the fuse didn't blow, everything has fuses to prevent what happened from happening, so someone either bypassed a fuse or ran their own wire, and did it wrong

 

[Cameron1591]

I was afraid some1 may have done some wiring wrong when I got the truck. The last owner told me he replaced the engine an tranny a few years back and I've came across a few wires that weren't properly connected.
Also I discovered the radio wiring was hacked up and "rigged" to an old dial stock radio and doesn't come in we'll or play through the new speakers well.
I'll start checking the things you described and tracing wires.
Thanks for the input.