So I've read a lot of mixed reports on whether or not this can be done. As anyone with an x-type, who has had to deal with bad catalytic converters knows, replacing them (especially the rear) is quite a troublesome and expensive job.

I've read about guys saying "seafoam it!", "BG44k it!" or the latest, "Spray gumout right in the throttle body!" (wouldn’t that strip the throttle body coating?) and other various methods.

Has anyone had success in de-carboning the converters while on the car? I'm skeptical to believe anything aside from replacement would be very effective however my wallet keeps screaming to search for a few more answers

 

You can't really clean the cats. your cats are either good or not, there isn't really an in between. you have the option of replacing the cats with a free flow model, but seriously, it will add about 2 HP at most. And the cost a fortune.

 

Yeah, I'm not convinced either.

After hearing (and mostly dismissing) the idea, I took it to a reputable muffler shop to get a quote for replacing them as I've read about guys having new cats fabbed by a muffler shop to save money over the OE fits. They basically told me they wouldnt touch it as it was way over their heads to install it in our cars. Thats when the manager of the shop told me that he had seen many used car dealers de-carbon cats and had success in getting them to work again. He did stress that he had no idea "how long" they would last as they were sold off and never heard from again.

Thought it was worth a post to see if anyone had any luck.

 

stshots, I have Seafoamed and BG44K'ed my car. I can't say that after the BG being used in the gas that I noticed any change. Granted, my car wasn't really having issues and I was simply doing this as a preventative thing. As for the Seafoam, of the things I have done, if something made an improvement, it was that. Granted, I sucked it directly into the engine and created one of the biggest smoke clouds you can imagine. I didn't put it into the gas and do it that way.

If you were to get a true "cleaning" of the cats, I would think that you would have to directly spray something into the cats and let that soak in and then run the car to get the cats up to temp. Anything else I think is going to get eaten up in the engine as if it is burning inside the cat, it will burn inside the engine, therefore leaving nothing for later. Atleast with the seafoam, you are running the engine rich, which will leave something for later.

If you have any more questions, just ask. I will tell you what I know.

 

When your cat goes bad its generally a rattle and its broken internally.
If you are getting a code from the cat, its the sensor.
You can't clean a broken cat and make it work

 

what would happen if you just removed it ,and put in a straight pipe, beside making a better sounding exhaust?

 

Thermo, I agree with you. Seems like it would be tough to get anything past the combustion through the fuel. I may try a bottle of seafoam just for the sake of saying I did.

Mike, I agree that if the cats are gone, they're gone. However I would hate to spend $2000 to replace cats that are potentially just clogged with a few good chunks of carbon and not actually broken up.

Ultimatley, I plan on swapping them out as my car has been throwing some pretty good fits lately with the only codes being P0420 and P0430. The o2 sensors are new. I've also "re-sealed" much of the top end of the engine to try to correct any problem that may have caused them to fail or throw the codes in the first place including IMT rings, PCV hose and upper plenum gaskets but am fairly convinced it was previous owner negligence with poor fuels and maintenance.

The gas milage is off, the car is feeling very choked with a noticable decrease in power, has been hesitating at lower RPM under load and it is getting worse as time goes on.

I admit, I am no ASE cert mechanic but I am good with a wrench and am absolutley no stranger to working on cars. I havent taken any of my vehicles to a shop for repair in over a decade as I just do it.

However, I could be very wrong about the issues and am open to any suggestions here as I have been very impressed with the caliber of people who use this forum.

 

I wish I could! Unfortunatley we have emissions testing in UT. I wouldnt be able to get plates.

 

Car would likely throw a code every time you started it too.

 

The cats are in a horrible spot, this is true. My advice would be to not bother with any chemical treatment of the existing converter hoping for a cure and instead spend your time looking for a skilled fabricator who has the talent to remove and replace the OEM cats with suitable less expensive aftermarket units. These guys are out there, you just have to search sometimes.

This is of course if you have determined that your converters are indeed faulty and/or plugged an you have ruled out all other variables - vac leaks, sensors, etc.

Good luck!

 

Any luck, i have the same delima right now

 

No dice so far... I have posted replacement instructions on your thread.

 

Benchmark makes direct fit cars that cost much less than OEM.

 

As does Davico. I like the Davico's a bit better but the Benchmarks are just a little cheaper and I can't find a Davico front converter. The Benchmarks are more accesible. Already have some on the way. I'll post once they are on and let everyone know how it went.

 

Getting ready to perform the annual maintenance on my `06. As I was buying stuff on Amazon, a recommendation came up for the 3M Do-It Yourself Fuel System Tune Up Kit. Has anyone tried it? Amazon reviewers rave about it. I know my ******* used to tell me that they apply BG44K when they thought they could rape me on the $650 annual maintenance (obviously they never succeeded). Does this stuff really work??

BG44K is only $19, whereas the 3M is $35.

Thoughts???

 

spiel, like I mentioned before, I have used BG44K in my car and didn't notice anything change. You can try the 3M stuff as I can't say that I have heard anyone say anything positive or negative about the product (forge the way to new ground).

As for cleaning products, for the most part, if you use quality gasolines, the need for a fuel system cleaner isn't that big of a need. Modern day fuels have more cleaners in them than I care to admit to. The only thing that I could possibly say is to run a different brand of gas periodically as the different manufacturers use different detergents and if you run the one brand for a long time, it may be missing something. By using the other brand, it stands a better chance of catching that missed thing from the normal brand.

 

Mt audio a6 has 2 cat codes plus engine coolant sensor is it possible that engine temp sensor will b giving a false reading making it believe the cats aren't working correct

 

Have tried magic juice and it will not bring back a failed cat. Convertor Warehouse out of TX has direct O.E.M. style replacement cats for unheard of prices. Have not used personally but I am about to.

 

If you get the chance before installing the new $$, try running the car with the MAF unplugged. Let us know if it gets confused or if it runs better.
Good luck with the fix!

 

It is possible to clean carboned up, but INTACT cats using lye (caustic) or citric acid (acidic). Not like new, but at least back to functional.


Here is the downside: you STILL have to take them OFF of the car.


Opinion: If you are in that far, spend the $300 for a set of replacements.