Hello everyone, I need some help figuring out which cats to buy. I have a 2003 with the 4.0L and the sticker underneath my hood says that the car conforms to epa regulations and California regulations. Does this mean I have to buy carb compliant cats? I was looking to buy cats for the 04-06 models since those come with all three cats and seem to be cheaper. I've been reading that they should bolt on fine to a 2003 model. Any insight is greatly appreciated. (I am looking to replace my cats to elimate a P0420 code)
Which Cats Do I Need For A California TJ?
- Thread starter ftft0101
- Start date
California catalytic converter? The expensive kind. As I recall they are all the same but have to have the CARB approval stamped/engraved into it. Won’t pass smog if the cat isn’t CARB approved. Same cat everywhere is cheaper because they didn’t pay for CARB approval.
At least that’s what I have heard. I don’t live in CA so what they require has no effect on me.
At least that’s what I have heard. I don’t live in CA so what they require has no effect on me.
jrussell505
New Member
Wont pass a smog because the guts of the CARB compliant vs Non-CARB compliant cats are different enough to cause the computer to know something is off and the vehicle performance with be negatively affected or everything is the same and they just simply wont pass it if the stamp isn't present
Requires the smog testing facility to crawl under your rig and verify the CARB EO is present on the catalytic converter. In my experience this rarely happens.
Never happened to me. They just hook up the computer if everything reads good you will pass.
jrussell505
New Member
It's a conundrum but I'll try to keep it relatively simple 
Jeep is currently in CA
Jeep is registered in FL and was ordered / delivered to South Georgia dealer when I lived in FL full time.
In the time that the jeep has been here, the cats went south and my fuel economy has tanked massively. Yes I've checked sensors and vacuum lines, etc and it's narrowed down to the fact that the substrate or whatever it's called in the mini cats has blown out or disintegrated and the o2 sensors are reporting the absence of that honeycomb filter to the computer and it's sending WAY too much fuel like 30% too much. I'm not registering it in CA as it won't be staying here for long, but under the hood it says it was shipped with California compliant exhaust on that "CATALYST" decal.
Question is two fold:
1) If I install EPA cats (both the Y pipe with mini cats and rear cat) this time versus putting on CARB compliant parts, will that upset the computer / o2 sensor / fuel trim such that will cause the engine to run too rich or lean or anything of the sort or will any difference be even noticeable?
2) If I go the EPA compliant parts route (which will be half the cost) I can't get EPA cats sent to CA because no one will ship them to CA. I don't want to drive it cross country with the horrible mileage it's getting due to the o2 sensors causing it to run too rich and use WAY too much fuel so I want to swap them before that drive takes place. If putting EPA parts on won't cause a problem with any configuration or such as mentioned in question #1, how can I best get a hold of these parts?? Is there a 3rd party that could / would receive a package on my behalf (even if i had to drive to Vegas or such to pick it up) that I could take back, install, and prep to drive cross country??
I really don't want to spring for CARB parts if it's not going to stay in CA.
Thanks for your time!!
Jeep is currently in CA
Jeep is registered in FL and was ordered / delivered to South Georgia dealer when I lived in FL full time.
In the time that the jeep has been here, the cats went south and my fuel economy has tanked massively. Yes I've checked sensors and vacuum lines, etc and it's narrowed down to the fact that the substrate or whatever it's called in the mini cats has blown out or disintegrated and the o2 sensors are reporting the absence of that honeycomb filter to the computer and it's sending WAY too much fuel like 30% too much. I'm not registering it in CA as it won't be staying here for long, but under the hood it says it was shipped with California compliant exhaust on that "CATALYST" decal.
Question is two fold:
1) If I install EPA cats (both the Y pipe with mini cats and rear cat) this time versus putting on CARB compliant parts, will that upset the computer / o2 sensor / fuel trim such that will cause the engine to run too rich or lean or anything of the sort or will any difference be even noticeable?
2) If I go the EPA compliant parts route (which will be half the cost) I can't get EPA cats sent to CA because no one will ship them to CA. I don't want to drive it cross country with the horrible mileage it's getting due to the o2 sensors causing it to run too rich and use WAY too much fuel so I want to swap them before that drive takes place. If putting EPA parts on won't cause a problem with any configuration or such as mentioned in question #1, how can I best get a hold of these parts?? Is there a 3rd party that could / would receive a package on my behalf (even if i had to drive to Vegas or such to pick it up) that I could take back, install, and prep to drive cross country??
I really don't want to spring for CARB parts if it's not going to stay in CA.
Thanks for your time!!
It's the same O2 sensor either way. The O2 sensor has no way to know what's in the guts of the mini-cats. The only instance where this would be remotely true is in the couple years where CA got the Precats and 4x O2 sensor setup and the other states were single cat 2 O2 sensor.
Regarding your question on the shipping, I'd look into forwarding services and have it shipped to them. Or to a friend in another state, or just call the company and explain the circumstances and ask if they can ship to you at the current address so you can get home safely.
Last edited:
It's a conundrum but I'll try to keep it relatively simple
Jeep is currently in CA
Jeep is registered in FL and was ordered / delivered to South Georgia dealer when I lived in FL full time.
In the time that the jeep has been here, the cats went south and my fuel economy has tanked massively. Yes I've checked sensors and vacuum lines, etc and it's narrowed down to the fact that the substrate or whatever it's called in the mini cats has blown out or disintegrated and the o2 sensors are reporting the absence of that honeycomb filter to the computer and it's sending WAY too much fuel like 30% too much. I'm not registering it in CA as it won't be staying here for long, but under the hood it says it was shipped with California compliant exhaust on that "CATALYST" decal.
Question is two fold:
1) If I install EPA cats (both the Y pipe with mini cats and rear cat) this time versus putting on CARB compliant parts, will that upset the computer / o2 sensor / fuel trim such that will cause the engine to run too rich or lean or anything of the sort or will any difference be even noticeable?
2) If I go the EPA compliant parts route (which will be half the cost) I can't get EPA cats sent to CA because no one will ship them to CA. I don't want to drive it cross country with the horrible mileage it's getting due to the o2 sensors causing it to run too rich and use WAY too much fuel so I want to swap them before that drive takes place. If putting EPA parts on won't cause a problem with any configuration or such as mentioned in question #1, how can I best get a hold of these parts?? Is there a 3rd party that could / would receive a package on my behalf (even if i had to drive to Vegas or such to pick it up) that I could take back, install, and prep to drive cross country??
I really don't want to spring for CARB parts if it's not going to stay in CA.
Thanks for your time!!
I had a non CARB catalytic converter shipped to CA. Purchased it from an eBay store and the seller had no clue. Computer won't know the difference.
It's a conundrum but I'll try to keep it relatively simple
Jeep is currently in CA
Jeep is registered in FL and was ordered / delivered to South Georgia dealer when I lived in FL full time.
In the time that the jeep has been here, the cats went south and my fuel economy has tanked massively. Yes I've checked sensors and vacuum lines, etc and it's narrowed down to the fact that the substrate or whatever it's called in the mini cats has blown out or disintegrated and the o2 sensors are reporting the absence of that honeycomb filter to the computer and it's sending WAY too much fuel like 30% too much. I'm not registering it in CA as it won't be staying here for long, but under the hood it says it was shipped with California compliant exhaust on that "CATALYST" decal.
Question is two fold:
1) If I install EPA cats (both the Y pipe with mini cats and rear cat) this time versus putting on CARB compliant parts, will that upset the computer / o2 sensor / fuel trim such that will cause the engine to run too rich or lean or anything of the sort or will any difference be even noticeable?
2) If I go the EPA compliant parts route (which will be half the cost) I can't get EPA cats sent to CA because no one will ship them to CA. I don't want to drive it cross country with the horrible mileage it's getting due to the o2 sensors causing it to run too rich and use WAY too much fuel so I want to swap them before that drive takes place. If putting EPA parts on won't cause a problem with any configuration or such as mentioned in question #1, how can I best get a hold of these parts?? Is there a 3rd party that could / would receive a package on my behalf (even if i had to drive to Vegas or such to pick it up) that I could take back, install, and prep to drive cross country??
I really don't want to spring for CARB parts if it's not going to stay in CA.
Thanks for your time!!
Contact the depth of motor vehicles in Florida and ask them if they look at part numbers on the cat as part of their visual inspection for smog.
As far as getting federal parts,have a friend ship them to you. Or do as duck doctor said
Florida. I ended up buying Walker CARB compliant catalytic converters for a 2004 model. They fit my 03' perfectly fine and have been working for the past 6 months.
WestCoastDan
TJ Addict
Looking at new exhaust options for our '03 as well, and I'm not seeing many that meet the CARB requirement here in CA. Those options that do are priced 2-3X the non-compliant models.
I also suspect that the smog test equipment here in CA wouldn't know the difference, but if the tech sees brand new exhaust - especially since the cats are right there for all to see when the hood is open & the vehicle is high enough for an easy peek underneath - then he will likely look for compliance markings.
I also suspect that the smog test equipment here in CA wouldn't know the difference, but if the tech sees brand new exhaust - especially since the cats are right there for all to see when the hood is open & the vehicle is high enough for an easy peek underneath - then he will likely look for compliance markings.
Check rock auto for carb compliant cats for an 04' model. They were a lot cheaper than the ones for an 03' and they fit without issues. The Walker ones I got only had the two cats near the manifold and not the third one though.
During my most recent smog test the tech verified the CARB EO on the two underhood catalytic converters but didn't pay attention to the one tucked under my low profile transfer case skid. Guess it depends how motivated they are.
Similar threads
