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Cleaning Catalytic Converters

Henman

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By rights this should be placed in general discussions but I cannot get my thread in there😢
I have a 2005 Allure CXL with the typical PO420 code displayed and searching through this forum I ran across using O2 senser spacers with limited or questionable success and from time to time I have watched YouTubes such as this

showing the use of Laquere thinner and in this vid Scotty uses one gallon of Thinner for half a tank. Has anybody tried this with success? The comments below his vids show many end up with the dreaded PO420 code gone and passing California emissions tests👍 Some mention the Thinner didn't work but removing and cleaning with soap did. Of course another fellow attempted to debunk Scotty's method but he didn't follow Scotty's instructions and only used a quart instead of a gallon! Many who commented on the "myth buster" mentioned "you didn't follow the instructions and only used a fraction of the Thinner!!"
Other than Scotty having thinning hair in the front😖like I'm experiencing does Scotty's cleaning method work?
Yes I did replace O2 sensors which didn't work as a result of taking it to a local fly by night garage where the idiot walked up to my car that was sitting for a half hour during winter, plugged the scanner in and had it idling and said you need new sensors! I should have given the finger and walked away because he didn't "light up the converter" or have the engine revving at 2500 RPM for a number of minutes to get the converter at proper operating temperature!! A total waist of money, unnecessary parts replacement and the return of the code! All that idiot knows is how to take a customers money.
 

2007LucerneCXL

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Illinois
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2007 Lucerne CXL. and 1995 Lesabre currently, past 1973 Riviera, 1968 Riviera
Cataclean is one of the better in tank cleaners, but not sure if it's going to cure the problem if the convertor is not operating correctly and is plugged.
 

Henman

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Not plugged just slightly below new spec. I can drive for hours continuously on highway and all's fine. Drive for days in my small town and all's fine. Drive in rush hour city traffic Bing on comes the $light! Garbage because exhaust doesn't smell rotten car is good on gas and that damn PO420 code😡
Nothin but a damn cash grab as we get cornholed because the Cat is 94% instead of %100. The upstream shows normal activity and the downstream shows slow very slight activity. The most maddening thing about that stupid code is it can be a number of faults or nothing worth justifying replacement.
 

2007LucerneCXL

Full Member
2,872
866
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Illinois
Buick Ownership
2007 Lucerne CXL. and 1995 Lesabre currently, past 1973 Riviera, 1968 Riviera
Unless you are going to take it to a qualified shop for additional dianogist, then going with the Scotty method and hope for the best is one solution. Let us know how it turns out.
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Sstevieboy0208

Buick Newbie
47
5
8
Cincinnati Ohio
Buick Ownership
2011 Buick Lacrosse
By rights this should be placed in general discussions but I cannot get my thread in there😢
I have a 2005 Allure CXL with the typical PO420 code displayed and searching through this forum I ran across using O2 senser spacers with limited or questionable success and from time to time I have watched YouTubes such as this

showing the use of Laquere thinner and in this vid Scotty uses one gallon of Thinner for half a tank. Has anybody tried this with success? The comments below his vids show many end up with the dreaded PO420 code gone and passing California emissions tests👍 Some mention the Thinner didn't work but removing and cleaning with soap did. Of course another fellow attempted to debunk Scotty's method but he didn't follow Scotty's instructions and only used a quart instead of a gallon! Many who commented on the "myth buster" mentioned "you didn't follow the instructions and only used a fraction of the Thinner!!"
Other than Scotty having thinning hair in the front😖like I'm experiencing does Scotty's cleaning method work?
Yes I did replace O2 sensors which didn't work as a result of taking it to a local fly by night garage where the idiot walked up to my car that was sitting for a half hour during winter, plugged the scanner in and had it idling and said you need new sensors! I should have given the finger and walked away because he didn't "light up the converter" or have the engine revving at 2500 RPM for a number of minutes to get the converter at proper operating temperature!! A total waist of money, unnecessary parts replacement and the return of the code! All that idiot knows is how to take a customers money.
Let me know if this work for you please asap. I'm getting the same codes
 

Rich B.

Active member
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Minot, ME
Buick Ownership
2016 LaCrosse & 2013 Boss 302 Mustang
Something as such just may work. Not sure about the newer brick design converters but the old monolith style perhaps? The thinner I’d imagine would increase the after burner effect to burn off contamination.

And way back they had the air pump to add extra oxygen to the exhaust for converter🤪
 

Sstevieboy0208

Buick Newbie
47
5
8
Cincinnati Ohio
Buick Ownership
2011 Buick Lacrosse
Something as such just may work. Not sure about the newer brick design converters but the old monolith style perhaps? The thinner I’d imagine would increase the after burner effect to burn off contamination.

And way back they had the air pump to add extra oxygen to the exhaust for converter🤪
My question is if it's safe for direct injection engines
 

Rich B.

Active member
487
81
28
Minot, ME
Buick Ownership
2016 LaCrosse & 2013 Boss 302 Mustang
I wonder? Direct injection is relatively new (in use that is for gasoline cars), converter shouldn’t of gone bad that quick. I’d look for another simple problem tied in with what might be throwing codes.

Very likely those are covered under extended warranty also, long after all others have expired. How close is thinner to fuel injector cleaner, maybe same stuff?
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Sstevieboy0208

Buick Newbie
47
5
8
Cincinnati Ohio
Buick Ownership
2011 Buick Lacrosse
I wonder? Direct injection is relatively new (in use that is for gasoline cars), converter shouldn’t of gone bad that quick. I’d look for another simple problem tied in with what might be throwing codes.

Very likely those are covered under extended warranty also, long after all others have expired. How close is thinner to fuel injector cleaner, maybe same stuff?
I think that they get a little dirty so I think I will try that to clean it considering that the car actually run and drive fine. Just a very slight rough idle so maybe that will fix it.
If someone used it let me know about the results
 

Henman

Buick Newbie
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Buick Ownership
Buick
Thanks for the replies everybody and for those in the same boat I feel your pain and suffering! This problem has been for a long time and here is one thing to consider as we will find out IF your cat is faulty and this is a great big IF?? one doesn't replace it until the cause has been solved IF in fact it even is a cat problem or something else overwhelming it making it trip a code??? Here is when and where miy adventure started other than purchasing in the first place😡😖
It started at a modest 80,000 miles or about 150,000 KM (sorry Canuckastan Sno Mexican with Metric BS shoved down throat) and at that time I had a slight buzz in exhaust when cold that went away after a minute as the exhaust warmed up. Result was intermittent 420. Later on Buzz remained constant and code was all the time. A Cummins diesel tech told me CHECK FOR LEAKS which of course was the buzz! He said he heard leaks can cause code headaches because when the engine is idling you have pulses of exhaust not steady pressure and between pulses or puffs of exhaust air can get in and trip a code! Well the asshole that ripped me for the not needed O2 sensors and myself examined the resonator while he was doing UNNECESSARY REPAIRS I.E. O2 sensors and we discovered the crimped joint or seam on the top popped open causing the characteristic exhaust leak buzz sound! He said he could chop it out and weld a pipe in its place. I said you don't have a pipe and by the time you are through messing around it will cost me more than getting a direct fit Walker resonator on Amazon which is what I did!! Quieter as well and this cut the constant 420 down to the intermitant 420 it is now! Lesson learned, leaks cause problems and false codes AND my $200 wasted on O2 sensors that were not needed to be replaced could have been used to purchase a new Walker direct fit Cat! Now back to the cleaning and several weeks ago I removed for several reasons, to determine if the bolts and studs were siezed and they were not, and to actually examine it. It looks undamaged and relatively clean. I sprayed it with Spray Nine expecting to see crap flow out and all that flowed out was Chrystal clear rinse water and dashed hopes of a solution! Back in it went and while getting an iexhaust system made for one other car I own I see a spark plug defouler on the display wall of the muffler shop I was at. The owner said about 70% success with them but $50 for this steel O2 sensor spacer. I didn't bother with it and his opinion was the coating or plating on the honeycomb was probably slightly washed or burned off causing a reduction in efficiency I.E. $$ I haven't tried cleaning other than the cleaner sprayed on and rinsed out. Another reason why I didn't try the sensor spacer is if we are attempting to fool the ECU, what effect will this have on gas milage? If it results in improper fuel mixture and wasted fuel it is wasting money instead of solving the problem?? It is to the point of giving up and purchasing a cheap cat on eeevilPay and hoping it isn't something else. This is where I'm at now other than this info and a while ago I used an OTC live data scanner with the cat hot and o2 sensors appeared to have proper readings. As mentioned earlier I can drive for many miles in my small home town or many hundreds of highway miles and NO problem! Take it to a city and drive aggressive in rush hour and Bing on comes the dreaded yellow light of $
This POS does not use excessive oil or burn antifreeze so we can rule this out and at 160,000/80-90,000 miles I replaced the spark plugs with correct OEM properly gapped as well. Most likely a cat running at 90-95% and GM wants my $ for a POS car.
 

DIY_KiNG

New member
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1
Buick Ownership
2010 Buick Lacrosse CXS
I have the same problem and I researched it thoroughly myself, and I have come to the conclusion that its an exhaust leak, albeit very small. Please see the youtube video below for a very easy and effective way to possibly resolve your issue. I have not done it yet, simply because there is no performance issue whatsoever ever with my car and I have a Launch CRP 429 scanner and checked the voltages of the O2 sensors and all, and as far as I can tell it more than a 99.999999% chance that it's a very small exhaust leak. HTH.

 

DIY_KiNG

New member
3
0
1
Buick Ownership
2010 Buick Lacrosse CXS
Check your catalytic converter to exhaust stud to see if any of them are broken. This is what I found on my car and going to replace them ASAP. See the image I posted. EDIT: The bolt might not be broken see GM part number 11561403 or 11546770 look at it in eBay.
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