Baystate Jeepers

So I chopped my muffler a while ago and drove for about 4 months like this before I decided I would put a glass pack on it. Now I have a healthy amount of back pressure and a more pleasant exhaust note. Every now and then I get a check engine light code p 0431 "warmup catalyst deficiency". I just clear it and it goes away for a while, but usually comes on when I'm muddin though higher water. I'm not worried about the code, but I do feel like one or more of my cats (3 in total because it's an 06) are failing because sometimes I smell the fumes when the jeep hasn't warmed up. Or I'll be on the highway and lose a little power because it feels like a blockage somewhere. Point is everything usually resolves itself.

Now that that's out of the way, here are my questions:

If I gut all (or just the one before the muffler) cats, obviously I'm going to get a cel. Is there any way I can permanently resolve this?

Yes I know this kind of mod is illegal. Yes I know it's bad for the environment. All the tree hugging granola crap aside, I want to gut my my third cat, if not all of them, and completely bypass the cel.

Is there a good tuner or something where I can just turn the O2 sensor values off? Or maybe a MIL eliminator that will work on the jeep?

I really just want to get it inspectable, the guys I take it to for inspection don't care about anything as long as the car seems safe and the cel isnt on.

Ideas?

On an EFI engine you need at least one O2 sensor to help manage the fuel delivery/mixture. The others are usually just for emissions, but may also tie in to the fuel control loop (I don't know)....

In some cases you can fool the computer with a simple R/C circuit which will provide a signal similar to an O2 sensor, but it is illegal, and will mess up the fuel system if it uses that O2 sensor to adjust the fuel mixture. This can work for the sensors just tied to check emissions... I've never done it, but the info is out there on how to do it.

JW

RLVRSK wrote:Now I have a healthy amount of back pressure ...

An engine is an air pump. Removing restriction increases efficiency.

Here's a nice article abot the back pressure myth.

http://mechdb.com/index.php/Exhaust_back_pressure_myth

RLVRSK wrote: Every now and then I get a check engine light code p 0431 "warmup catalyst deficiency". I just clear it and it goes away for a while, but usually comes on when I'm muddin though higher water. I'm not worried about the code, but I do feel like one or more of my cats (3 in total because it's an 06) are failing because sometimes I smell the fumes when the jeep hasn't warmed up. Or I'll be on the highway and lose a little power because it feels like a blockage somewhere. Point is everything usually resolves itself.

Now that that's out of the way, here are my questions:

If I gut all (or just the one before the muffler) cats, obviously I'm going to get a cel. Is there any way I can permanently resolve this?

Yes I know this kind of mod is illegal. Yes I know it's bad for the environment. All the tree hugging granola crap aside, I want to gut my my third cat, if not all of them, and completely bypass the cel.

Is there a good tuner or something where I can just turn the O2 sensor values off? Or maybe a MIL eliminator that will work on the jeep?

I really just want to get it inspectable, the guys I take it to for inspection don't care about anything as long as the car seems safe and the cel isnt on.

Ideas?

I would start by replacing the bank 2 downstream O2. I think you said you had 39K on this Jeep in the other thread?
There is no way to modify the factory ECM, that I know of, to eliminate the O2 sensors. Even if you could, the engine would run like ass without closed loop feedback. IMO, any kind of gutting of the cats is just butch - besides the fact it's probably a welded system and would be a PITA to weld back up. In addition to that, cats are worth money! Anywhere from $50 - $100 each! Hollowing them out would be tossing money away. In addition, the Federal warranty on emissions systems (i.e. cats) is 8yr/80,000 miles. If it is your cats, then they could be replaced by a dealer.