Does anyone know what o2 sensors are on a federal emissions equipped Xj?
Is there one in the engine bay and one down by the main cat?

I have a cali emission with the two upstream and 2 down streams, I bought a computer with code 634AF. I’m wanting to install that computer and run the two upstream o2 sensors on a header. I already have this setup but with the cali emissions computer and it is running lean and burning valves/seals

A search on another forum says 634AF is a Federal Emissions PCM.

https://store.allcomputerresources.c...-computer.html

Yours should be a 635AF CA Emissions.

https://store.allcomputerresources.c...-computer.html

Federal is 1 O2 before, 1 after.

Thanks for the reply, I will have to remove the harness from a federal emission Xj it sounds like. I was hoping to just plug the computer on and use the two upstream o2 sensors I have now.
Is the o2 sensor before the cat located on the header?

Well to turn it into a "factory" Federal emissions will use the Y pipe, Walker 52439, where the dual cats are.
You will use the Walker down pipe, 53440, that goes with that and the bung for the O2 sensor is at the end just before the rear cat.
You will you use bolts in place of where the O2 sensors are now in the 2 piece exhaust manifold.
Or I guess you could just leave them there. LOL.
The Walker rear cat, 16117, has the bung at the end just before the muffler.
Or maybe you could weld in a bung on the round rear cat that you have on the Jeep now.
You will want the one of the 2 engine wiring harnesses that have 2 connectors to the PCM with the fuel injector connectors on it, O2 sensor connectors, etc.
Might do this someday cause I came across a Federal Emissions '00 in the boneyard and grabbed the wiring harness and PCM.
And since I already replaced my exhaust a number of years ago with Walker parts, dual cat all the way back, already have all those parts in that I wrote above.
Except the Y pipe which I sourced for fear that at some point they might become N/A.

Are you planning to "convert" your CA emissions vehicle to Federal? Not to be a "narc" about it but:

"Under Title 42 USC:yada:yada;yada: Motor Vehicle emissions prohibited acts:The following acts and the causing thereof are prohibited—

(3)(A) for any person to remove or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this subchapter prior to its sale and delivery to the ultimate purchaser, or for any person knowingly to remove or render inoperative any such device or element of design after such sale and delivery to the ultimate purchaser; or

(B) for any person to manufacture or sell, or offer to sell, or install, any part or component intended for use with, or as part of, any motor vehicle or motor vehicle engine, where a principal effect of the part or component is to bypass, defeat, or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this subchapter, and where the person knows or should know that such part or component is being offered for sale or installed for such use or put to such use;"
https://www.govinfo.gov/content/pkg/...tA-sec7522.htm

I'm simply trying to inform you. There may be state laws governing this as well. You may do as you wish. I don't know of anyone prosecuted for violation. The real impact is if you're subject to emissions testing where you live.

Swapping out your entire exhaust system can get expensive too.

Perhaps you should "back up a bit" and explain what going on? You have a lean condition and you think the PCM is the culprit? Your earlier posts only talk about a roll over.

I know it’s illegal and also know that it’s against the forum rules, don’t mean any disrespect to the forum or moderators I’m just trying to make it run better and warn other people what will happen if they do the same thing.
I have a JBA header with two bungs for the upstream o2 sensors installed, I’ve had it like this for a while but it burns oil now and gets 10 mpg.
Thank you Ralph for the reply and info, going to the junkyard asap

https://www.cherokeeforum.com/f2/ann...rum-com-rules/

Please refer to #11 in the link above.

This is kind of a grey area, we didn't used to allow it at all, but since local laws are what your state goes by, and states decide on emissions, it's up to you to know and follow your local laws.

We will say this...if you decide to do a delete, you do so at your own risk. It's solely your responsibility.

Technically it’s Federally illegal to sell the vehicle after you convert it. My 01 is a Cali emissions Jeep. The sticker under the hood says it’s California Emissions. You can’t sweep it under the rug for it to go away once converted. A guy making $13 an hour doing emissions might not know the difference between federal and California emissions but the next owner might eventually figure it out and since you converted it illegally your leaving yourself open to legal prosecution. Just something to consider before you proceed. Even if you live in a non-emissions testing area because it’s federal law.

We've already been down this rabbit hole. We decided that it's the vehicle owners call. We do not condone anything and will not advise one way or the other. It's the vehicle owners responsibility.

Happy to share I hooked up HPTUNERS to my jeep and turned off the rear o2’s, also plugged them back into the harness. Averaging 15mpg now combined city/highway and in the mountains of NC. If I ever had to sell this jeep I’d make it clear that it won’t pass emissions and of the “tune”.
🤘🏿