PatchworkPatty

Ok, long story short (ish). Was swapping out a starter motor and when I was wiggling it back into its tight little spot, for some reason had the battery hooked back up. yes, I know…
Shocked pretty good, then smoke but couldn’t tell where from since i was underneath the truck. then fire. yes, fire. got it out with an entire fire extinguisher.

The damage. there’s a wire grounded to the back of the block that’s also grounded to the cab by where the heater hose goes through the firewall. why? i don’t know nor do i remember putting that there, but I obviously did at some point when i was doing the swap. that wire completely melted not from outside temps, but from overload inside, clearly. Also the power steering line is toast.
But, more importantly, it is completely dead now. Battery seems ok, but there is nothing. No dash light etc. nothing. I’ve been looking but can’t find any main fuse that is toasted.

Where and what should i be looking for? Did I completely kill the one thing I love?

Also, could I have fried the computer? what about the starter that made the connection that sparked it all, would that have been damaged?

This is on a 3.4 v6 (from a 2000) I swapped into my old truck (1988, replacing the 3.0) about six years ago. It’s been awesome, has taken us from Oregon to the bottom of south america, where we currently are so while some parts are easy, others are more difficult, and also not being in a city, having limited access to help and the places you know and transportation etc adds to it all.

I really need some help here, I’m pretty alone on this, so any thoughts or anything would be greatly appreciated. Also, time is sorta of the essence as well, seeing as my vehicle permit is almost up in Chile, so i need to cross into argentina soon, but kinda need to be able to drive the truck, to be able to drive it to and across a border haha.

Thanks so much for any help you might have.

fierohink

You probably popped one of the main fuses. These are big square fuses rated at either 50A or 80A.

The fried wire will take some more digging. Can you follow both ends? Was it the trigger wire to the starter?

PatchworkPatty

Yeah that 80amp looked ok but I’m trying to find another one right now in this little town. But is there another one somewhere that could have blown?

and could that one fuse make the everything electrical go dark?

the fried wire i replaced. it was just a ground connection bolt on the firewall and to the same thing on the back of the block. only about it a foot long. it just doesn’t make sense to me, that that wire got so overloaded, and it doesn’t go directly to anything.

the wires to the starter motor feed through that 80 amp block fuse. but those wires themselves seem to be fine.

PatchworkPatty

[QUOTE=fierohink;52472848]You probably popped one of the main fuses. These are big square fuses rated at either 50A or 80A.

Would that one fuse be enough to lose 100% electronics?

2ToyGuy

A quick glance at the schematic here shows clearly that there is one wire supplying all the power to all the vehicles electrics. I am pretty sure that it's not just a "wire", but it's a fusible link. I would wager it burned open , whether you can see it or not. It's designed to allow the wire inside to burn open without going through the insulation.
A quick test with a multimeter would tell the tale. Ohm end to end of that wire, and I wager it reads open.

Make sure you replace it with a identical, OEM, item, if you can. It actually functions as a high amperage fuse, so it's important to the system. If you can't get an identical, OEM, fusible link from someplace, you CAN replace it with a regular 10 or 12 AWG wire, but I would replace it ASAP with a fusible link again.

You should, as well, verify every fuse you can find. I don't think too many of them will have blown, but it's important to check NOW, rather than once you have a new fusible link in. That way you aren't chasing down problems you could have found in the beginning of the whole repair process.

Hope this is some small help...
Pat☺

EDIT: A large number of systems pick up their ground through that wire. It's absolutely vital to the functioning of the vehicle! I can't absolutely speak as to just WHY it cooked when you fried the rest, but you should definitely replace it immediately. The spark plugs get their ground through that wire, as do any number of other systems. VERY important, indeed. Check the alternator's ground wire, too.
Heck, check ALL the grounds. You ran a huge surge through the entire electrical system, and it not only went through the "hot" wire, but it had to go back to the battery, and thus it went through all the ground wires. Check them all, from the battery outward. You may well find more cooked wires than you may think you will. Small insurance in any event against future, hard to find, problems.

​​​​​​​Pat☺

Malcolm99

The wire at the back of the head is the main engine ground, you need that connected, I'd check all grounds as thats where the power went and burned, and then start checking fuses and testing/replacing the relays in the fuse box as they also have grounds, main power, EFI, starter, ect.

PatchworkPatty

ok here is what i found so far:

i found the fusable link, but it was connected to nothing. i probably erroneously left it off when i did the engine swap because with the 3.4 i had to move the battery to the other side, so it would no longer reach the positive terminal of the battery. so it was just hanging out the bottom of the fuse box with the 80A fuse in it. i assume that is why the fire started (because it wasn’t attached to burn out)

i checked every ground i could find, including the alternator ground and they all looked fine. i also already replaced to burned up ground from the engine block to fire wall…but curious what gauge should that be?

i have checked every fuse and relay i can find and everything looks fine as far as i can tell.

so now, i am recharging the battery (which got drained in the surge), and replaced the 80A fuse (even though it looked fine) and replaced the ground from engine block to firewall. i know i need to replace the power steering line since it melted, but what else can i check???

2ToyGuy

The hot to the starter, the big wire direct from the battery.
I would also check the ground to the engine block, again, a large gauge wire directly off the battery negative terminal down to the AC compressor mounting. If no AC compressor, it's usually bolted on where the mount would go.

The ground on the back, from the head to the firewall is usually 12 GA, IIRC. When I replace a ground, I always go one size up. If Toyota used 12 GA, I use 10 GA. It's served me very well so far. Sure doesn't hurt anything.
I always figure that Toyota is trying to save money and weight, so if I go one size up, I'm in good shape. Granted, it's a small thing, but they add up. A lot of little things can add up fast. I now have a little wiggle room as far as current carrying capability. If I want to add something, I already have the increased current capability.

I would take your battery to a auto parts store or mechanic that can do a Load Test on it. It's common for a cell or two inside the battery to be bad after an episode such as yours. A regular multimeter can't do a load test, and once the battery is charged will indicate a perfectly good battery. It takes a special, heavy duty tester. Most auto parts stores that advertise battery testing can, and will, do a load test for you for free. You may come to regret it if you don't get a good load test.

Did you put a new fusible link from the battery to the engine compartment fuse block? IIRC, there should be one between the alternator and battery as well. The heavy wire from the bolt on the side of the alternator, under the red rubber cover. Worth a quick ohm check.

Keep us in the loop
Pat☺