o2 sensor simulator????

[2000xj4x4]

i cut my cat off about 6 months ago (along with the stock muffler) and welded a dynomax muffler in place of the factory one. I also left the o2 sensor where it was right in front of the muffler. About a month latter my CEL came on and my jeep started missing really bad and idling real low but it only does it every once in awhile and im assuming the has to do with me removing the cat. has anyone had this problem after removing the converter? i already used sparkplug nonfoulers as spacers to pull the o2 sensor out a little which just made it worse. a friend of mine suggested an o2 sensor simulator on ebay but it looks like a scam. id really like to get the problem solved without buying a new cat cause they're pretty expensive and i threw my stock one away.

P.S. i already tried repacing the o2 sensor. and louisiana doesnt check emissions.

[2000xj4x4]

alright well i guess i'll just have to put a cat back on it and see what happens

[Blaine B.]

Without a cat, you'll have less backpressure. There's a large debate on this....

But the o2 sensor behind the cat doesn't control the engine, it only checks to see if the cat is working or not.

The o2 sensor on the downpipe controls your motor. Take it to autozone and see what code you are getting, it could be entirely different.

Especially since it threw a code an entire month later.

[RaccoonJoe]

I agree with Blaine. I'd get the codes checked, just to see what's happening in there. You might find something totally different.

I had a 96 s-10 that lost a cat one day due to an accident with a Saw-Z-All and a welder. I spliced in one of those "MIL Eliminators" off E-Bay, and it shut off the check engine light. I didn't have any engine problems without that eliminator thingy....I just had crappy MPG. Put that box in place, and the mileage came back up.



*and don't listen to the crap about no cat = no backpressure. It may very well be true, but I've never seen it cause problems, as long as there's a muffler on there. I did it to my XJ, and the only "problem" that may be related is a small drop in MPG. 'course, that could also be due to a heavier foot, longer warm-up times in the AM, and winter gas....


*edit* I did a bunch of research before using the MIL Eliminator. Search that phrase in Google, and you should get links to some turbo mustang forums. They have *huge* debates about whether these things work or not....but the general consensus (and my experience) is "Yes"

[2000xj4x4]

alright thanks i'll look into the MIL Eliminator i noticed a pretty bad decrease in mileage also so i really need to get this taken care of.

[pierceME311]

The MIL eliminator is the way to go, I used them on my contour SVT when I installed headers without pre-cats and they work great. They are not a scam and can work on any OBD-II system. There are however, some very crappy ones out there, make sure you get a good set and they will be fine. This is definately a get what you pay for product.

[JNickel101]

didnt think you could use a MIL Eliminator to replace the upstream O2 sensor....?

[Blaine B.]

I believe you can, it will fool the computer into thinking the fuel/air mixture is just right.

[McQue]

so explain something to me...if you want to improve your mileage, and get the right fuel/air mixture to fix a poorly running engine...maybe rich, maybe lean, and you are getting a check engine light...why would you spend good money on a good mil eliminator to fool the computer into thinking the fuel mixture is correct?

Maybe I misread this thread, but it seems like you need to start with finding out what the DTC code is... If you install a mil eliminator, how will you know when your fuel is running too lean? or rich? Do you have a Fuel/Air ratio guage installed?

Most people can smell when something is running rich, but I believe there is a recent thread about a motor that was running lean in one cylinder and now that piston has a whole in it...

McQue

[UNCC_99XJ]

Originally Posted by McQue

so explain something to me...if you want to improve your mileage, and get the right fuel/air mixture to fix a poorly running engine...maybe rich, maybe lean, and you are getting a check engine light...why would you spend good money on a good mil eliminator to fool the computer into thinking the fuel mixture is correct?

Maybe I misread this thread, but it seems like you need to start with finding out what the DTC code is... If you install a mil eliminator, how will you know when your fuel is running too lean? or rich? Do you have a Fuel/Air ratio guage installed?

Most people can smell when something is running rich, but I believe there is a recent thread about a motor that was running lean in one cylinder and now that piston has a whole in it...

McQue

You're not the only one who intrepreted it like that. I'd rather spend the money in properly fixing the problem then fooling the computer into thinking that it's fixed.....but maybe i'm reading this wrong.

[XJ01-08]

Heres what im thinking about getting since i took off my pre cats and my lengthen the wires to locate the sensors behind the main cat didnt work.

http://thefastman.com/02Simms.asp