highvoltagefeathers

So I'm looking to get new stainless headers (crack in the "collector", sure that's a surprise to everyone) and running a 2.5 exhaust system with a magnaflow muffler and high flow cat.

I have a 1997 Cherokee sport with the 4.0, and want to include an electric exhaust cutout in the section that crosses just behind the oil pan so I can push a button and be the loudest car on the block . Just for kicks, and maybe a smidge more power in the higher revs.

I know that there are 2 O2 sensors on the jeep. One just downstream of the headers (before the planned location of the cutout), and one on the backside of the catalytic converter (after the planned spot for the cutout).

Something tells me that the O2 sensor just behind the headers would be the only one the fms listens to in order to adjust the mixture, and that the other 02 sensor is just there to spit code if your cat is broken so you can go pay a dealership to replace it.

But I want to be sure that if I do include the cutout and a check engine light comes on when I open it, that its just letting me know that it thinks my cat. conv. is busted, and not burning valves and screaming for help cause of a lean mix.

Thanks!

Feathers

ZINGGG

Well you are correct in thinking that the upstream o2 is the only one of the two that determines air/fuel mixture. That's quite an awesome idea you have there. I hope you take lots of pictures and do a write up of you go through with it!

odgreen

fist thing first. installing a cut-out in front of the cat is illegal and against the rules to talk about in this forum. second jeep 4.0l need back pressure to run correctly. you eliminate the cat its going to bog down and run like crap.
3rd its will cause your ecu to run in limp mode running lean.
dont be a douche and put a cutout right after the manifold...

odgreen

cf rule #5
Illegal Activity
5. Do not talk about illegal activity on this forum. This includes illegal drugs, parties, wheeling, internet use, etc. Violators of this rule will be dealt with on a case by case basis. This rule includes the discussion of removing catalytic convertors, this is illegal and not allowed to be discussed on this site.