EHarris

Who has done this job in the driveway? My 08 is throwing the O2 Bank 2 codes for the last 10k and now it's coming on once a week. Im due for CA Smog here by March 23rd also. Has anyone does this job recently themselves and do you happen to have the part numbers or confirmation that the part numbers in this post are correct? I have an 08 JKU 3.8l.

https://www.jk-forum.com/how-tos/a/j...nverter-407293

Quadratec sells one with the 02 censors pre-installed? Will this work in CA?
https://www.quadratec.com/products/57605_0000_07.htm

Rock Auto
https://www.rockauto.com/en/moreinfo...33352&jsn=2037

karls10jk

I've removed and replaced this guy a couple times when doing a clutch. Getting the clamp off where that one slips into the intermediate piece is about the worst piece of it. I ended up using an air chisel to 'push' the intermediate piece towards the rear axle. I've had an exhaust leak at that joint since doing the job.

Job wise- not a terrible thing to do. Spray down your clamps now and maybe even order the Mopar clamp to replace it so you can expedite the process. The U bolt clamps don't work here so skip them. Loosen the pipe with a twist, lubricant, and little taps (air chisel) and use a ratchet strap on the rear bumper to help pull the exhaust pipe back and away from the piece you're replacing. Loosen up those 4 from the exhaust manifolds (good time to replace those if you suspect you've got cracks there, particularly the driver's side) then unclip the o2 sensors. From there, it's just gently working it out from the control arm mounts which should be easier with no control arm brackets.

I'm thinking more on this now- you might have to remove the crossmember and auto skid bar to get this piece out. That requires pulling the t case skid plate as a well. When you pull the transmission crossmember you'll want to support it with a jack while you work. Jack placement is key because you don't want something so large that it'll be in the way of you working the exhaust pipe out.

EHarris

I was just thinking of replacing the entire system. The exhaust manifolds got replaced under lifetime power train warranty twice now. I just figured after 175k from there straight through and a new muffler Is that crazy? Was also thinking about the EGR Valve at this point too. Ignition is all new, plugs, wires, coil pack and pcv valve (seated properly now lol).

Am I missing anything here? How about removing the fender flares for better access? I've done the transmission pan so I will place my jack accordingly that's a good tip.

karls10jk

I'm typically a big proponent of early PM but I think replacing the muffler is not necessary. That being said, I've replaced mine. I backed into a rock bank and it cracked the shell on the muffler. But I don't see a point in otherwise replacing it.

As far as removing the fender flares for access- if your factory captive nuts break loose then yes, you may want to pull the flares. My Dorman replacements have the manifold threaded so there is no nut on top which makes it much easier to tighten. If you decide to do the EGR then yes, pull that flare. That's worthwhile every day of the week in my book.

I'm working on replacing the plug wires at 215k miles, just haven't quite got there yet.

EHarris

OK so I can just do the CAT and new O2 Sensors. Is it possible that my CAT is good and its just an O2 sensor or at 175k its just best to get it over with? I am trying to find a CARB compliant CAT right now for CA at the best price. I'd want to stick with all mopar sensors. My biggest concern is getting the clamp off where it disconnects from the exhaust pipe. I'm hoping my impact wrench would break it free.

karls10jk

Absolutely possible that the cats are fine and it's just a sensor. I'm at 215k on my original cats. When I pulled them down for the clutch, they still looked to have the honeycomb in tact.

Mopar sensors or NTK- I bought a NTK after stretching the wires on one of mine and it's the same sensor that came out of the vehicle.

As to that disconnect- the impact wrench may be able to break the clamp free but then you've got years of corrosion and carbon holding the two together. I sprayed lubricant into the joint and hammered away with the chisel to slide it back. If it's sensors then you don't have to worry about this though.

EHarris

I guess I would hate to change all 4 sensors and then still have the code come back and have to pull the sensors out of the old and put into the new. It seems pulling O2 sensors out of a vehicle with 175k is also a challenge. How would you handle this? P0430. Im geting the code about once per month now.

captainstabbin

I was getting that code on my 08 and bought some stuff from amazon that cleared the code for a year that allowed it to pass the emissions test in PA. When the code came back and added the stuff again and it took the code away and again the vehicle passed inspection. It was $15 for a can. If your interested I can try to find the product. I ended up trading it in for an 18 in June.

karls10jk

You're in a pretty predicament. I'd check out some of those cat cleaners and see if that'll get you to a place where it'll pass. I have an 03 Rubicon with 250k+ that has that code and the cat cleaners will eliminate the code for a day or two then it'll come back. For that, I think there's a leak upstream or the cats are bad.

For the JK- I'd buy the sensors and replace them. I pulled my one that was stretched (broke the wires) at 120k and it was relatively painless- even though I lived on the coast and it was frequently submerged in water. I saw no evidence of cat issues when I pulled them for my recent clutch work at 210k miles. I'd just hate to fork out $2000 for cats when all you really need is $200 worth of sensors. If they're bad then you can go replace the cats and move the sensors. Once you've pulled them then they'll be easier to get out.

Removal tactic for me was spray it down before driving my 40 mins to work, work all day (cool down), drive home (heat up), then hit it again with spray when I got home so it could seep in as it cooled. Repeat the process until you're ready to tackle it. As I mentioned, the sensor really came out uneventfully and that was using a standard wrench. The ideal solution would be those fancy O2 sensor sockets but I didn't have one.

Mr.T

A few thoughts: P0430 is for low cat efficiency. But in addition to a worn out cat, it could be an exhaust leak or aged O2 sensor (upstream aged compared to downstream). If the cat cleaner spray works, the cats are probably wearing out.

Edit: Graphing the O2 sensors output might be able to confirm a bad cat. If the oscillations at the upstream sensor are seen at the downstream, the cat isn't working. Comparing banks 1&2 is another technique. Might be worth some technician time as opposed to trying parts. Buying the OBD equipment is another route, but it's like any investment of time and money -- takes a while to pay for itself.

Generally I'd stick to Mopar or NTK sensors, and replace in pairs (on each bank). O2 sensors can get damaged by clanking them around when removing or installing the cats -- first hand experience on that. In other words, I'd remove any sensors worth saving before removing the cats, and then install sensors after the cats are bolted in. New bolts and clip-nuts for the flange connection to the exhaust manifold are worth getting unless they have been recently replaced.