Electrical shortage/failure help

Right, I've got quite the dilemma here. My 1999 tacoma and I where 1000 miles into a road trip and coming down a forest service road that I camped on, when suddenly the truck starts lerching really hard, the odometer starts going nuts, and the dash is flashing on and off. Stopped the truck, waited a bit and kept going thinking id be okay. Well, smoke came into the cab but only a little before it stopped. If i tried to turn my blinkers on, I could watch the odometer fluctuate with the clicking of the blinkers and if i tried to turn the headlights on the engine died. Took it to a mechanic who replaced the battery terminal clamps and discovered that the ground wire for the tachometer on the back of the engine had melted and snapped right half in two. Got that replaced and didn't have the time or money for them to dig in and find the root cause, low and behold it happened again as i was almost home on the freeway. Same thing, melted ground wire and a shit load of arching. Ive traced both the main negative terminal and positive leads, no arch burns or loose connections that i can find. All of the fuses are perfectly normal. Any ideas?

 

So that red wire with the yellow connectors, must be the new ground strap, that thing keeps melting in half? You have pics of it melted while installed in the truck?

 

I dont, and youre correct that the red wires the ground. It was in almost the exact place that the new ones at. I just noticed that theres no battery negative to body wire, or battery to frame wire. Would that cause the only other ground wire to get over loaded? ive already added in an 8 gauge battery to body ground wire and am considering adding another battery to frame ground just for the hell of it.
I dont think adding more grounds would really matter as it doesnt fix that theres a massive power surge happening at somepoint caused by something that I cant find

 

The negative post on the battery should have a strap on it going straight to the firewall there inside of the fender right there. Does it not have that ground?

 

Nope it only had the one wire going to the engine block

 

Lemme go grab a pic of mine

 

Yeah, looks like they've replaced some wiring on yours. Wonder what that was about?

 

I likely pulled that wire out, it was spliced for the shity lights the last guy had wired in and i thought it was just a ground wire for the lights so it came out with the rest of that harnest. Does 8 gauge hold enough current to be there as the ground wire?
That wires been gone for almost a year, why would it just now start to act up?

 

8 gauge wire is fine. Yeah I think you have more going on as well. Hard to say though. What else has been modified? I think you'll kinda have to get to square 1 where we know what is original and what's been nodded, etc. Also, did that ground burn up at the same time both times? Like when you turned on the headlights? Hopefully there are some commonalities to help us know what direction to head in. But ensuring the grounds are there and functioning correctly is definitely a start

 

I have no idea when the grounds burnt up. Only commonality was rough/bouncy road conditions at the point of major failure. I just added a 4 gauge negative to frame ground to soak up whatever amperage is coming from that electrical shortage. Personally, im selling the truck as soon as I can so if this extra ground wire stops the gauge cluster ground from melting im going to call it good at this.

 

Now the trucks accelerating choppy and inconsistent. Maybe the coil is fried?

 

there should be 3 ground wires, one from the DS inner fender to the negative battery post, one from the firewall to the back of the head and one from the negative battery post to the block. If all of these are corroded the return path for the electricity back to the negative post will find its own path, throttle cables will melt etc. There can be high resistance in the ground cable and the cable can "look" fine.

 

Some how the electrical load was going through that one ground .

Grounding into aluminum is not the best

I wonder if the one going to the block is either broken or corroded to the point it can no longer handle the load.

It also sounds like after market wiring was done

 

I have a 98 and when you lose the ground to battery from the fender EVERYTHING goes dead. I have no tach in mine so can't say to the cable melting.

 

@TheBluePhaantom2 The only commonality is the bouncy road correct? I can't tell very well by the picture but does your battery have a hold down strap attached?

I had a buddy who used an after market Optima battery on an old 4x4 Datsun and he melted his Neg cable in a similar manner because (as he was going down bumpy forest roads) the battery would jump up and arc across the battery posts against the metal hood

 

Good point I don`t see the hold down where it would be stock!!

 

I didn't notice this either. Good eye man
@TheBluePhaantom2 bruh you got that battery and the basics in order right? All those things have to be done or intact for a reason. But the battery could be arching out by moving around