did exaust mod and now poor mpg! help!

f100ranger · 11-09-2009, 10:02 AM

the other day i bought a cerrybomb turbo muffler to put on the jeep and i ended up cutting the cat off and now have a header running to a turbo muffler and i removed the o2 sensor from the old cat so now i only have one o2 sensor and i have noticed its smells like i am running rich and my gas milage has droped and the check engine light is on what can i do to fix these problems! im a broke college kid with no job any more and gas milage is very important now! thanks

**Unlimited04** · 11-09-2009, 10:07 AM

Quote:

Originally Posted by f100ranger

the other day i bought a cerrybomb turbo muffler to put on the jeep and i ended up cutting the cat off and now have a header running to a turbo muffler and i removed the o2 sensor from the old cat so now i only have one o2 sensor and i have noticed its smells like i am running rich and my gas milage has droped and the check engine light is on what can i do to fix these problems! im a broke college kid with no job any more and gas milage is very important now! thanks

put the O2 sensor and cat back on the way it was. they're supposed to be there. you completely wasted your money removing those items, and now you need to put them back in place.

spnkr94 · 11-09-2009, 10:12 AM

Quote:

Originally Posted by Unlimited04

put the O2 sensor and cat back on the way it was. they're supposed to be there. you completely wasted your money removing those items, and now you need to put them back in place.

X2...you need both o2 sensors.

00tjtyler · 11-09-2009, 10:16 AM

you need to put the cat back on to regain the mpg's and the o2 sensor or it will get worse. Plus im pretty sure cutting the cat off is considered illegal in most states.

f100ranger · 11-09-2009, 10:16 AM

could i fab a second o2 sensor on and leave the cat off? i never liked the way it sounded with it on there.

ckisela · 11-09-2009, 10:18 AM

you must go to Community college....

Dmcastino · 11-09-2009, 10:20 AM

You really should put the cat back on man, its there for a reason.

**Jerry Bransford** · 11-09-2009, 10:21 AM

The downstream 02 sensor has nothing to do with the air-fuel mixture. Its sole job is to monitor the cat for proper operation and light the Check Engine light if the cat isn't functioning properly. It does nothing else, it cannot affect the air-fuel mixture.

Something else has happened, how is your upstream 02 sensor? That is the one that if it goes bad can ruin your fuel economy by setting it full rich.

**grogie** · 11-09-2009, 10:22 AM

This would be a good addition for the things I regretted doing to my TJ thread.

f100ranger · 11-09-2009, 10:27 AM

how do i check the o2 sensor that is up stream to make sure it is functioning properly?

MUDDYSAHARA · 11-09-2009, 10:27 AM

and why do you want it to sound like a log truck......cherrybombs are for hotrods with big motors, not a straight six.

03rubiconMG · 11-09-2009, 10:31 AM

i cannot see how not running a Cat can effect fuel economy its just there for emmisions i believe.

The issue lies in the O2 sensors. Try drilling and tapping the O2 sensor that you left off back into near where it used to be and see what happens, or switching which O2 sensor you left out. As jerry said only 1 of the two sensors monitors fuel, maybe you left that one out. and the one that monitors the cat in.

00tjtyler · 11-09-2009, 10:33 AM

you can also try cleaning the upstream o2 sensor with a propane torch i believe if i remember correctly chemicals will effect it.

Tyler99TJ · 11-09-2009, 10:37 AM

I cut out the caton my Jeep, but I cut it off just behind the sensor. My check engine light did not come on and it has a little more power. I would not cut it off if I did it over because it doesn't make a noticeable difference.

f100ranger · 11-09-2009, 10:39 AM

can i just buy two new sensors and replace the one i have on right now and add the second a coulpe of inches before the muffler?