Exhaust, too hot???

I have been trying to figure out for a while now if my exhaust is running too hot on my 99, and if so, what can I do about it.

Background: I pulled the carpet and herc'd the interior a few summers ago. Love it, but sometimes when the Jeep is running hard the tunnel and floor on the pasenger side would get hot enough to "melt" the herc, or at least soften it up so it smelled.

Set up: For a number of reasons, including smashing the entire exhaust, I just ended up redoing my exhaust. I added a new cat (generic one from Summit) and welded in an 02 bung. I stepped up to 2.5" tubing now versus the 2.25" stock. After the cat I have a glass pack muffler and then 2.5" tubing out to the back. I added some floor/tunnel shield from DEI under the floor for the whole length of the exhaust.

After finishing this on Saturday, I drove it around and ran up a few hills pushing it a bit. Everything sounds great, seems to run fine, no CEL, so I assume everything is hunky dory. It smelled funny though, so I hop out and see that the muffler is smoking. I assume it's just stuff burning off the new parts, but it seems to be REALLY hot. The end of the muffler attached to the cat has turned black and the stainless steel band clamp looks like it has changed color too. I happened to touch the tail pipe at the rear near the bumper and burned my finger.

So with all that said, how hot is too hot? I can get access to a IR thermometer, so if I get temps, what is a normal operating temperature (on the outside) for the cat, muffler, and piping? I have read that running rich will cause this, but I assume the computer on the 99 will automatically adjust the fuel/air mixture. I pulled a plug out and they still look brand new after 10K miles. Is there anything else I should check?

Help would be greatly appreciated on this!

A lean running motor will cause it to run hot, this was proven to you by pulling a plug with 10k on it and still having it look brand new. A properly firing cylinder will cause the plug to have a slight tannish color to it. How old are those oxygen sensors?

Well I'm not sure if this means anything...but the clamps I used on my new exhaust I installed the other day changed color after a good 30min of driving. And my exhaust till smells a little, and it's been a week...but it smelled really bad in the beginning. It's just a process of burning all the oil and crap inside the muffler, as you said.

As for your muffler turning black...could be what's coming out of your engine causing that? When's the last time you replaced your cat?

Brand new cat.

The o2 senser behind the cat is brand new. The one is the "downpipe" is still stock I believe, never replaced it.

I'll have to get some pics tonight, but what I should have said was the plugs looked good, maybe not brand new. They were a slight tannish color. There ws no build up on them and they looked clean.

get some airbake cookie sheets and attach them the the bottom of the floor pan above the exhaust. It will keep the herc and stuff in your floor from melting.

I had an airbake in there, and it got smashed, so I might rework that.

I am looking to see if the exhaust running hot this way is normal, and if not, a way to fix it, not cover up the symptoms. I know ther are lots of ways to shield the driver's/passengers' compartment, so I am not worried about that. I am more wondering if there is something mechanical or otherwise I need to attend to.

The one before the cat tells the computer how the engine is running. The oxygen sensor after the cat tells the computer if the cat is doing it's job.

ive put a couple diff exhausts on my eep and it ususally smells for a week or two as it heats and burns off factory oils and such. i have also burnt my self on the tailpipe, the exhaust heats up the entire system pretty well all the way to the end.. has always seemed normal to me as ive noticed this on every vehicle i gotten too close to the tail. as to whats too hot... good ?.. maybe on fire