Difficult to imagine that a bad catalytic converter could potentially take a perfectly running XK8 to the scrapyard right?
This was / is the dilemma that I have been involved in for the last couple of months as I attempt to get through CA smog with my 2003.
Two months of searching for parts with nearly zero result. I finally had resolved that I was going to have to attempt building a cat myself and even prepped a number of parts to do so.
Been running on a temporary permit since beginning of November and had to get an extension that runs me until the end of the year. I am hopeful that this allows me enough time to finally get this off my plate.
In the eleventh hour, I stumbled on a set of used cats on eBay but they are not the ideal ones by any means.
50-State cats off a 2003-2006 XKR with 78k on the donors clock. My car is NOT a R but after doing some panic searches on the part numbers and reviewing the pics closely, it does look like the same physical design and I am hopeful that they will boltup without any issues.
Then comes the real rub in all of this - will they work?
My car is an original CA car from 2003 and I suspect even then, would have CARB approved emissions.
The cats I bought are 50-state cats and I am nervous about them not running clean enough to avoid a CEL just because they don't scrub the air enough vs California cats?
Not sure how close the two were in smog performance back in 2003 but I am keeping my fingers crossed that with them being relatively low mileage cats, they may just sneak me past.
It's my bank2 cat that is causing the issue so I plan on just replacing that one first to see if the problem resolves. If that works out, I will replace the other side as well because my car has 180k on the clock and it certainly won't hurt it having fresher cats on it, especially since the bank2 cat failed me.

Just a word of caution to other 2003-2006 owners that you should protect your cats at all cost. My failure was self-induced as I ran the car too long on what turned out to be a failed mass airflow sensor.
Will never make that mistake again as finding replacement cats for these model years is next to impossible or prohibitively expensive for the age and / or value of the cars currently.

I will post an update once I have the parts installed to see where this takes me. If it doesn't work, I am not sure what my next steps will be at the moment.

 

Sorry not much help BUT when I went down this road in my 2014 XJR. I also purchased a used (65K miles) cat off EBay. Worried it would not pass emissions the same as you. It all worked out fine and the car passed without problems. BUT it is a risk because with used parts you just don't know what your getting. I also read where it was illegal to sell used cats by the EPA. So not sure how or why used ones are sold on EBay? I am very glad I got it! Jaguar wants $2400 EACH! Even used I had to fork out $500+.

I looked at sport cats and after market ones as well but again like you I could not be sure they would make the car pass inspection or not. The 2014 XJ uses the same converter for the V-6 and V-8 engines and I installed one from a V-6 car.

Here are a few things that I ran across but did not use.

China is now making the catalytic bricks that go inside the converter housing. I saw a guy who cut open his bad cat. Measured the brick inside and found one with the same dimensions on AliExpress. Got it and welded up his old cat housing with the new brick inside. He said it passed just fine. They come in all sizes/geometries. Now would I trust one of these? I don't know but my car was 30 days out of inspection and I could not get it inspected until the cat was fixed. So I was interested.
Inside Cat Bricks

There is a company Davicomfg that makes after market Cats. But they only have the right one for your car and their notes say it does NOT pass Ca. emissions. So no good for you.
Davico Cats

The reason I posted about them is when I had my problem they also only offered one side for my car and as luck would have it. The wrong side!
I contacted them and they were very open to adding to their product line and said if I was interested I could send in my old cat. They would copy that and release it. No need for a working cat as what they need is a pattern to copy so they can match the piping.

I did not send in my old one and they still only offer the side I did not need. It will work for Federal emissions but again NOT for Ca. emissions.
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I'm not sure if they will work but I have a pair in my shop I just took off a '97 XK8 CA car.

 

A hefty price tag on those, but my plan is to buy a pair for my Xkr 4.0

https://swallows-jag.co.uk/product/s...l-sports-cats/

 

Yeah, I ran the entire deal on everything I could find. We have cars that were only made for three years vs. the previous 4.0L cars that ran for twice that long so aftermarket on the older cars seems easier to find.
What helped me to score these in the 11th hour was my search criteria on ebay. Instead of searching for anything to do with "cats", my search was for "downpipes" and that is what showed these and others. Maybe also why some of these breakers are allowed to list them and ship them to CA?
They arrived yesterday so not the work can commence. Hoping for no big struggles swapping them out and very hopeful for a result at the end.

 

They do not bolt up to the 2003-2006 model years. If only they did, we 4.2L guys would have more options.

 

Nice work but I was surprised to discover that one manufacturer - and maybe even this one - uses an off-the-shelf magnaflow cat that costs like 130.00 US.
That's a lot of profit for welding up the ends and the bungs. I get it that it is design, jig, materials etc. but it feels like being held to ransom a little bit.
There are just so few options for these model years that it allows a vendor to basically set whatever they want in price as long as it is still less than the factory parts.

 

Sounds like we need to contact “Davicomfg” as mentioned in post number 2 above and do more in-depth inquiry about their manufacturing offer. Every owner of these model years will eventually likely find the need for replacements if they keep and drive their cars.

I doubt Jaguar still has these manufactured…so…

Davicomfg might find incentive in that it seems they would be the sole world-wide manufacturer!

Brian W.

 

Hey that's great you found a used one! Let's hope it is good and you pass emissions.

Can't answer about how they can sell them other than there are so many people selling things I don't think the government can keep track of them all regardless of what the laws are. EBay certainly could care less until they are prosecuted for this.

Yes I did not bring up the Swallows ones. They are very well done but expensive as posted above. That link brings up another thing I could never find a straight answer on? Looks like the OEM's use 400 cell cats. Most sport cats are 200 cell but these Swallow units are 300 cell. I was told by people selling the 200 cell cats that they will not pass emissions?

Will only 400 cell cats pass emissions? I guess again it depends on what the laws are where you live. But I have to pass inspection and finally just went back stock to avoid any problems with passing.

Just a note? It's been 1.5 years and about 6K-8K miles since the used replacement was installed plus another yearly inspection and all is well.
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Certainly seems like the right path as they have one of the two already designed.
Hopefully someone hooks up with them before a single XK8 is lost to the lack of available parts to keep it on the road.

 

Keep an eye on fuel trims. If they're not flagging codes but are off where they should be then your cats may suffer reduced lifespans.

 

Set up an LLC in montana, title/register it there, no smog needed.

Any aftermarket cat you use in CA will need a CARB EO or you need to find a smog shop that doesnt care. The cats being nigh on inaccessible on these cars is the one thing on your side - i have a smog shop local to me that smogs my Miata that's missing one of its catalytic converters, but they haven't noticed yet because the sportier header i replaced it with is hidden under an OEM heat shield. Theyve smogged it like that twice now.

 

OEM cats should be 600 cell, so rather obstructive

 

Yes, very good intel on that.
As I said, I did this to myself by not taking the myriad of misfire codes, etc. too seriously. The trims were intimating an airleak on bank 2 but nothing severe.
It wasn't until I got a "restricted performance" alert that I decided to take the problem seriously but alas, by then it was too late.

 

I bought a used pickup truck a couple of weeks ago and the owner had just had it smogged. I asked where he had it done and it was the same shop I was intending to bring it to. He said they didn't do anything but hook up to the computer to check for codes and IM readiness which is a relief. Since these will go on and look 100% stock, I doubt anyone is going to do much to prove anything different on the worse of occasions. Still, fingers crossed that the parts get me through those codes and IM readiness in the first place.

 

On another note albeit complete snakeoil.

Since I will have a stock cat that is for certain disrupted due to overfueling, I am going to poke around with the idea of seeing if it can be cleaned.
Obviously, I have zero expectations on whether or not it can be but it does provide an opportunity to have a look at it anyway.
Was already considering what types of chemicals there may be out there they may be able to breakup the blockages without damaging the materials.
Will probably keep the old cats onhand for someone elses emergency should I be able to see a difference using a borascope.

 

Well good luck as I thought the same thing! At least at first!
I ran several bottles of Cataclean thru the car which at $26 a bottle is not cheap. Does it work? Will it work?
All I can say is it did not work for me.

I finally got the code to go away by using various spacers and "mini" cats screwed into the O2 ports. But within several months the cat efficiency code came back and after removal of the cat. I found the honey comb inside the cat had collapsed and completely blocked the O2 port!



After seeing the above I gave up and replaced the cat.
I have also read that when this happens it can fill the exhaust pipe up with broken chucks of the cat. Sometimes even plugging the muffler. Mine did not go that far and it looked like the honeycomb pieces all stayed inside the cat.
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I think that this thread will become more and more important as our 2003-2006 cars age.
Hopefully, some manufacturer out there will put together a cat package that is designed solely to keep these cars on the road and not necessarily a performance upgrade.
Yesterday, I pulled the bank2 cat off of my car. Happy to say that it came off without anything stripping or breaking. The day before, I decided to crack all of the nuts between the cat and the exhaust manifold and then shot some WD40 over each nut. I believe this soaked in overnight and facilitated an easy removal. Only needed a deep well 13mm socket and a pair of wobble extensions (short, long). Made sure to keep the socket tight and straight on each nut and gingerly got each one off.

Although I was suspect, I had seen a vid on YT that showed someone getting one of the studs out of the cat using the torx head on the stud. I can say 100% that for my rust free CA car, this did not work. Almost immediately, I snapped the head off of the stud - so defintely be diligent on getting a socket on the nut to remove the cat - not the torx head on the stud.
I had to do this as the used cats I purchased were missing one of the M8 studs each and one of them had a cut M10 stud. Once I had my old cat out, I had access to the studs I needed and using heat and double-nutting on the stud + a little hot WD40, I managed to get the studs I needed without damaging any of them. I am going to reuse the O2 sensors for now as they were reading fine on my software. If I run into issues, I won't have an issue replacing them with new if that is what is necessary.

Today, I am moutning up the replacement cat on bank2 and then I will know 100% that it was the issue and fingers crossed - the initial problem will be resolved. If that all goes well, I will then proceed to replace the bank1 cat as I have a pair. I am holding off on that until it is proven to me that these cats work on my car. Since bank1 is more fiddly to get access to, I consider it a time saver until the repair is verified.

I did have a thorough look at the old vs replacement cat last night. I looked into each cat on the manifold end and did notice a difference between the two. The replacement has clearly defined passages in the media of the cat and the old one that I removed has what is obvious collapse of media. So, this cat doesn't appear to be a candidate to fix unfortunately. I thought I would see stable - but blocked media but it defintely looks collapsed or eroded. Whichever descriptor is more accurate. If I find the time post install, I am going to take the angle grinder and cut the top off of the old cat to clearly show how they collapse when they go bad. I tried taking a photo but it is so deep and subtle through the camera lens, it is very difficutt to have it show up. Cutting the top off the old one will make it easy to see.

For those interested in the conclusion to this repair, please stand by and I will have an update posted in the next 24 hours I suspect.

 

Very good point about removing the stud! I also have a rust free southern car and the studs did take heat and time and spraying penetrate to get them moving. Yes forget removing the stud with the external fitting on the stud! Mine was not Torx but had flats on two sides of the stud for a set of pliers.Use the old fashion double nut method.

Here is the stud and nut I used. I had to order them from Jaguar. At first I thought these should be just common exhaust studs. But after buying several from my local parts store they all were different in one or more ways. Note this was for my 2014 with the 5.0L so not sure how many cars used this stud. Check it with a jaguar dealer parts site before ordering.



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Couple of updates.

- Ok, I screwed myself slightly with the purchase of these 2 cats. Although the bank2 cat physically goes on without any issues, the bank1 cat is of no use to these cars as it lacks the connection for the EGR pipe. The good news is that it is the bank2 cat that is causing the issues so in the end, I probably did not need the other one although it would have been nice to mount them both as a set. I was in a panic when I saw the listing and literally took 10 minutes to research before hitting the buy it now button. Someone out there will need a low mileage bank1 cat for a 2003-2006 XKR, so I am not overly concerned about getting some funds back for that.

- Car is back on the ground and I did do some testing yesterday. I still have the 2 monitors not reset. The evap and the comprehensive but I suspect that I need to get her out for a good drive today to see if those monitors finally reset. As I looked at my SDD software live data, I still see a difference in the display of bank1, O2 data vs bank2. THat led me down the rabbit hole last night in understanding more completely what I am looking at and what it means, when also including fuel trims. I know I have only ever changed one O2 sensor on the car and that was on bank1 so the sensors on bank2 are pretty old. Not saying there is anything wrong with them at the moment as they ARE both active. It is just that they might be very tired and that may be the reason for a variation on the results in SDD. Heading to the car here shortly to retest a bunch of things to make some verifications and update my understanding.

- For those that have swapped out O2 sensors on these model years, what brand os sensor did you choose? If I find it necessary, I would like to pick up at least 1 sensor - even if just to do some comparison work on the readings I am currently getting. What I have learned that is super helpful is the differences in how the wideband sensors work vs narrowband and how they correlate to the fuel trims too. I waded through quite a few unhelpful videos but did find a couple that corresponded to the setup on these cars. Will post my results later today for those that may need to understand things better. Fingers crossed.