So I drive a 1990 Jeep XJ. Last week, it wasn’t starting/running and while trying to diagnose the issue I stumbled upon a mystery tubing piece. I was underneath the car, and on the right side of the transmission, I have a tube that’s not connected to anything down there. It’s the same material as the vacuum tubes in the engine bay. It seems to run up towards the motor around the area where the tranny fluid dipstick is, but I can’t pinpoint its origin. I finally got the car running and driving today, but it’s idling kind of rough. Could this be related to the tube? Does anyone know where it’s supposed to go? There’s another tube next to it that runs to the neutral safety switch

 

Might be the breather for the front diff... post a picture so folks can see exactly what it looks like.

 

It comes from up towards the engine bay

Runs alongside the tranny

And just isn’t connected to anything. The whole engine is very shaky and sounds like it’s glugging along when it’s running

 

Trace it back to the other end. Guesses are - axle, transfer case, or transmission.

BTW, i have never seen the exhaust tack welded directly to the crossmember like that before. Should be a rubber hanger in there so the exhaust can move a little.

 

My buddy said it sounds like not all of my pistons are working, but I’m not sure how to diagnose or fix that

 

I've tried to trace it to but I lose it around where the tranny fluid dipstick is

 

Check compression.

 

how do I check that

 

watch this...

 

Vent tube photos in this thread. https://www.cherokeeforum.com/f2/np2...filter-227368/

Vent has no vacuum, if that's what is not connected. Looks like a vent tube size wise.

 

Roger that, exhaust should'nt be welded to something solid. And is not how my 90' hangs with factory setup. Looking for a cracked exhaust manifold which are pretty common with that design already.

 

it was like that when I bought it I guess, but is that something that I need to unweld?

 

Yes. When you give the engine gas, it rocks side to side. When this happens, the exhaust rocks a little with it. This is part of the reason why exhaust is hung using rubber, to absorb the shock, as well as keep the vibrations down. Because the exhaust is welded solid, there is no movement. So, when the engine rocks side to side, the exhaust is being twisted more than it was designed to. The header on the 4.0L already has a reputation for cracking the collector as it is, even with a rubber hanger. That welded tab just speeds up the process. Something is going to give, and that weld looks solid, so my money is on the header cracking.

So, yes. Unweld it and buy the proper hanger.

 

do I need access to a welder or can I just separate it with an angle grinder?

 

A Sawzall would work nicely.