1995 4.0 XJ died while cruising....then wouldn't restart....

Hi. Well to start off, this evening I was welding up my cat and muffler. Previously had them clamped but that was leaking a bit so I decided to weld them. I'm not a welder and I just was able to borrow a friend's welder yesterday....I practiced last night and this afternoon and was able to weld up my exhaust with a 110 volt flux core welder.

Earlier in the day I welded about half of what I needed to but needed to run to the store to buy more wire. I took the XJ and that was all fine and dandy. Came home and finished welding up the rest of the exhaust. About 6 welds in total, with the ground from the welder being attached to the "air injection" tube coming out of the side of the cat.

Later that night I took the XJ out for a cruise. I was about a mile from home when the XJ just died and cut off. I was traveling about 45mph at the time. I was able to coast to a side street. I turned off my headlights, restarted it, and then flipped my headlights back on. It immediately died and would not restart.

So I tried starting it various times (it would crank but not fire) and even unplugged the crank sensor a few times, nothing would help. I did not check for spark (obviously did not have it!) but did check for fuel and I did have fuel.

So I waited about 45 minutes to an hour for a friend to come by with his truck and tow me home about a mile.

After towing I decided to just try and start the Jeep again....and what do you know, it fired right up.

I replaced the crank sensor as well as the cam sensor about 3 years ago exactly.

The cam sensor I purchased from a smaller local auto parts store. I am not sure what brand of it was but it was a good brand.

On the other hand, the crank sensor I popped in was from AutoZone. Not sure if it was Valucraft or Duralast.....

The symptoms seem to be screaming "crank sensor" but is it really possible for the new AutoZone unit to fail so soon? Or is it just the usual Valucrap and Dura$hit garbage?

I am thinking my welding did NOT play a role in this and it is just a coincidence. I am guessing that if it were to destroy the PCM it would have immediately. And besides that, it was running perfectly fine besides the time when it died and would not restart!

Let me know what you think. The AutoZone part was a 3 year ago thing. I don't really buy anything from AutoZone anymore....so if I do get another crank sensor it will definitely not be from there! I was thinking about getting a few from the junkyard from low mileage XJ's. I know when my original crank sensor failed it had over 178,000 miles on it. Original as far as I know...but now I have only around 31,000 miles on this AutoZone crank sensor....

Thanks.

BTW it's a 1995 with 4.0, AW4 and NP231

Crank sensor is always the bet for intermittant conditions. You could try heating it up while running with a hair dryer or something, and if it dies, spray some cold water on it to see if it restarts.

Just curious--did you disconnect the battery before welding? Both times?

No, did not disconnect the battery or PCM at all during my exhaust welding. Didn't think I really needed to for such a small weld job although I have heard conflicting things, mostly about structural welding to the unibody though...

Last time I remember when I replaced the crank sensor it still wouldn't work and it actually ended up being the cam sensor. That was 3 years ago, probably the AutoZone garbage is at fault this time as I believe the cam sensor was of a better brand and quality.

Just for future reference, oxy/acet. welding OK, but if using anything else I recommend disconnecting BOTH battery cables.

It started fine earlier this afternoon. About an hour ago I took it for a small cruise down my block. Had it running for about 5 minutes. Drive back to my house and it dies in the middle of the street, will not restart.

Going to grab a crank sensor ASAP.