brestored

So driving down the road and the jeep dies and I see smoke. I jump out and lift the hood to see a small flame by the firewall. I blow it out and investigate to find that the braided ground strap that goes from the wall to the head had gotten so hot it melted and caught fire to the vacuum hose and a few wires right next to it. I repaired everything, I believe but now the jeep runs really rough. I wonder if this has reset the ecu and now it has to "relearn"? I don't know what was the cause of this issue. I am going to refresh my grounds and replace that braided strap with a coated/stranded wire. If anyone has any thoughts on this issue or the rough idle/running I would love to hear it. Thanks

brestored

It's an 89 4.0

Slick761

Wow you must have had some serious resistance.... or something overloaded it. Does the strap still get hot?

DFlintstone

Almost had to have had a short...bat cable to engine ground somewhere. Did you leave a beer can under the hood?

DEOR

x2 for short

Turbo X_J

Probably way past time for PM.

brestored

I haven't noticed the strap still getting hot. I drove it a around for awhile after repairing things and had no other issues aside from running rough.
No beer can, but I will be checking all the cables +/- both.

cpnwrench

WOW! first I ever hear o' that !!!! Well lets see, you had the braided ground actually red-hot enough to catch fire (or all the grease and gunk and road grime caught fire that was on it)..but seriously, with that kind of arc-ing going back to ground, your charging-starting-battery system has a serious issue....like the previous posters said, double check ALL grounds, and power distribution......

as for running rough now,, well you did catch fire in there,, so maybe them vacuum hoses melted more than what you can visibly detect. (they are very brittle too, I found out the hard way!)

well, best of luck sir, post us back and let us know what you find!
I know I had to replace BOTH the POSITVE and the NEGATIVE battery cables on mine recently as 'Ol Red was not starting correctly. once I did that...she's a beaut now!

all the best!

cpnwrench

cpnwrench

oh yeah, if I am not mistaken, the MAP sensor is mounted up near that area....can you pull codes on it an see if maybe that heat damaged the MAP sensor....?

just a thought

cpnwrench

brestored

Looks like I've got it fixed. There was another wire that was damaged and the vacuum hose to the map sensor was disconnected. Didn't even notice it till I starred looking for signs of damage on the sensor. Jeep is running good once again. Thanks to all for your input.

Moncheche

You can see how hot the ground strap was on my 2000 XJ.
Here's the strap. It melted in two.

This is why. The battery broke loose, jumped over next to the alternator, and the top of the post came in contact with the hood. The battery cable has also worn through and was rubbing that alternator.

Moncheche

I threw several layers of shrink tubing over the hole, and finished with a few wraps of electrical tape. I made a new (temp) ground strap with three runs of 10g solid wire.

Runs like a kitten now. (well, a kitten with serious medical issues)

CCKen

Moncheche,

That new ground strap at the fire wall IS the definition of Bubba'd.

LOL