Jeepaholic
TJ Enthusiast
I did the defouler trick. It does work. But that was only for about a year for 2 reasons-star station smog was required, and it really smells not having any cats, especially when driving slow offroad
Catalytic convertor removal
- Thread starter badlieutenant
- Start date
I don't understand all this hate for cats. Its better for the environment, plus is really sucks being behind somebody who doesn't have them. And in today's world where I can buy 50mpg, or 700+hp cars that can do 10s in the quarter, what performance is lost? We've come a long way from the 70s.....emissions and performance can coexist.
Jeepaholic
TJ Enthusiast
My only hate for them is the fact that ca must be ca certified, which cost 3 times as much...
Kristin
New Member
Hi all.....
I have had the cat problem with my 04 4l..... This is what happened.... They remeoved all the cats which were just burnt out lumps of black coal and removed the third cat as well which was clogged with the stuff from the other 2 cats.... To do all this without it throwing codes it had to be coded out of the pcm.... That was pricey.... But it worked.... I now have no cats and no cat sensor related codes.... However.... The idling every so often goes a bit off... I think it might be that the empty cat bulbs are still there so my back pressure isnt hundred percent... Need to save up to have a free flow fitted all the way through now.... Oh yah.... I live in south Africa.... No emission laws here....
I have had the cat problem with my 04 4l..... This is what happened.... They remeoved all the cats which were just burnt out lumps of black coal and removed the third cat as well which was clogged with the stuff from the other 2 cats.... To do all this without it throwing codes it had to be coded out of the pcm.... That was pricey.... But it worked.... I now have no cats and no cat sensor related codes.... However.... The idling every so often goes a bit off... I think it might be that the empty cat bulbs are still there so my back pressure isnt hundred percent... Need to save up to have a free flow fitted all the way through now.... Oh yah.... I live in south Africa.... No emission laws here....
My 97 is missing the cat. Once in a while I'll get a CEL for the cat. Shopping for a replacement as I'm not fond of the pig rich smell. Nothing done to the O2's, no spacers etc....One O2 code in the last 4 months that disappeared when the battery was disconnected.
Airjunky
TJ Enthusiast
Digging up an old thread as I look into exhaust systems for my 02 4.0. When I bought the Jeep, the PO had already modded the exhaust....a header, the stock lower section, which I think is where the cat's are located with all four 02 sensors in place, a bolt on pipe by the skid plate, a glass pack, the a tailpipe. It was a bit loud, but not bad. And it ran great before the engine spun a rocker bearing. No codes are being logged.
The muffler is totally rusted out & the pipe in the cat's place has 2 seized bolts in it. Plus the tailpipe is sitting right on the right rear shock. So I'm thinking about replacing it all with a Flowmaster super 44. But I haven't found that cat pipe anywhere yet through the skid plate yet.
And how far back do I need to run the tailpipe to keep the exhaust out of the cabin?
Any suggestions on where to get that pipe thru the skid plate?
In the pic, the section on the right......are these pre cats? So the section thru the skid plate, this must be a post cat? Think I should replace it? Or run a straight pipe again with the muffler between the skid plate & rear diff?
Oh, and I live in Washington. ...no emissions testing after this year.
The muffler is totally rusted out & the pipe in the cat's place has 2 seized bolts in it. Plus the tailpipe is sitting right on the right rear shock. So I'm thinking about replacing it all with a Flowmaster super 44. But I haven't found that cat pipe anywhere yet through the skid plate yet.
And how far back do I need to run the tailpipe to keep the exhaust out of the cabin?
Any suggestions on where to get that pipe thru the skid plate?
In the pic, the section on the right......are these pre cats? So the section thru the skid plate, this must be a post cat? Think I should replace it? Or run a straight pipe again with the muffler between the skid plate & rear diff?
Oh, and I live in Washington. ...no emissions testing after this year.
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I know this is an old post but how would my Jeep run if I took out the pre cats and the main cat and kept the stock muffler. Also would it sound good if I did this?
Do you think I could remove my main cat and leave the pre cats and keep the o2 sensors without throwing codes and also would that sound good if I removed the main cat and left the stock muffler?
Yes, I did the exact same thing on mine. No CEL codes or anything. It did make it noticeably louder, but only really at full throttle and higher RPMs.
Awesome. I’m having this problem right now where yesterday I was driving and I got the engine reved up pretty high and i heard a noice so I reved it up pretty high and it did it again and then my check engine light started flashing and it felt like I lost some power and my Jeep exhaust sounds different now. It sounds a little deeper almost like a v8 if you really listen to it. I ran the codes today and I got po300 all cylinder misfire and cylinder 4 and 6 misfire As well. I threw a can of sea foam in to maybe clean everything up but I’m leaning towards one of my cats might be clogged. What do you think?
Could be the pre-cats, but more likely it’s a coil pack, spark plug, or short in the wiring.
When I read the title I came in all prepared with my abundance of knowledge about which live traps to use, what kind of nip they like, and how many will fit in a burlap sack relative to how many bricks to use to make sure it never leaves the... oh hell I'll just stop there.
Yeah I replaced my plugs last year with some auto lites that Jerry Branford Recommended. So i think what I might do is talk with a shop and maybe see what they think because I’m thinking about replacing the pre cats and just cutting out the main cat. And it could very well be the coil pack as well.
1995XJ&2006TJ/LJ
New Member
It depends on what year is it. My 1995 Jeep XJ wouldn't run over 55 mph, looked in the muffler caved in...so I cut off the muffler, ran like new, a couple weeks later wouldn't go over 45 mph, now the cat was clogged with, I was like well, it's got to go. Cut it off and had about 2-3 feet exhaust from the headers. It was load as hell with open headers, but I ran like it was new again. It never acted up and a check engine light never came on. I ran it like that for months until I had the money to install a new exhaust. 1996, had stricter epa regs compared to 1995, and again stricter in 2001 I think for the 4.0. Those years might throw a code, but not the older 4.0's with their simple computer and simpler distributer. 1996 and up, I'm not sure most likely would throw a code.
1995XJ&2006TJ/LJ
New Member
Well, our 4.0's are torquey and get awful mpg. When I was running with open headers it gained me about 3-4 mpg. When I put on a new exhaust I went back down to 15 mpg no matter how easy or hard I would drive it.
I've got the Flowmaster cat setup sitting in my garage waiting to go in over the next few weeks, along with 4 new NTK O2 sensors, and then I'm going to take it to a muffler shop to get the rest done. I figure I'm doing the environment enough of a disservice with this gas guzzling hog that I could at least make it run as efficiently as possible. I'll probably get a nice quiet muffler, too. I'll get an old muscle car if I want something loud. The Jeep is loud enough, being a brick that's forcefully slammed through the air.