Catalytic Converter replacement
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Intermediate
Joined: May 2016
Posts: 37
Likes: 27
From: SF Bay Area
Catalytic Converter replacement
Hi All, My car is a 2005, 997.1 Carrera S with 175000 miles. For the last 3 months I have been getting the error code of P0420 ( Catalyst system efficiency below threshold Bank 1) and I have applied all the initial remedies such as total fuel system clean up and spraying directly into the plenum, etc. However, after a couple of hundred miles of driving, the error code reappears. I have two questions. First, are there any thing else I can do to pin point the problem to the Cats being old and worn out? Second, if I have to replace the Cats, other than the OEM option, are there any reasonably priced, reliable options that are CARB compliant (for California) that I should consider? Any help will be appreciated? - Robert
Drifting
Joined: Mar 2013
Posts: 2,578
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From: Bay Area on the Peninsula
After 175,000 miles, how much longer do you expect the cat converter to last? If you have to replace it, either get a used Porsche one, or a new Porsche one. Where you are, SF Bay, you fail smog if they look at the cat and it's not Porsche.
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Joined: Oct 2014
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The cat got stolen off of my F250. CSAA sent me to a shop with 100% coverage and free welded cage to avoid future theft.
The replacement cat was not OEM. When I took it to the smog station the test took an extra hour while Sacramento looked up the cat status. I passed because the aftermarket cat was state approved, but it was more of a hassle.
Meanwhile, back to the 997.1 ... Those messages are internally stored but not throwing a CEL. Thoughts??? I'm thinking there's a problem getting through a cleansing cycle, but I am not sure why that would be the case.
The replacement cat was not OEM. When I took it to the smog station the test took an extra hour while Sacramento looked up the cat status. I passed because the aftermarket cat was state approved, but it was more of a hassle.
Meanwhile, back to the 997.1 ... Those messages are internally stored but not throwing a CEL. Thoughts??? I'm thinking there's a problem getting through a cleansing cycle, but I am not sure why that would be the case.
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Joined: Oct 2007
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From: Clemson, SC
Someone who lives in a state that doesn't do emissions testing who upgraded their exhaust to 100 cell or 200 cell cats must have some OEM ones kicking around they'd be willing to sell for a couple hundred bucks.
I'd sell you the ones off my 997.1 but sold them a out 10 years ago to someone that needed OEM looking cats but was going to cut them open and remove the material to pass visual inspection somewhere.
Maybe reach out to the aftermarket exhaust guys as owners who have them install upgrades may not want the old parts - maybe Soul Performance, Fabspeed, etc or even eBay or LA Dismantler since they're liquidating everything and going out of business.
I'd sell you the ones off my 997.1 but sold them a out 10 years ago to someone that needed OEM looking cats but was going to cut them open and remove the material to pass visual inspection somewhere.
Maybe reach out to the aftermarket exhaust guys as owners who have them install upgrades may not want the old parts - maybe Soul Performance, Fabspeed, etc or even eBay or LA Dismantler since they're liquidating everything and going out of business.
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Joined: Sep 2018
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From: Sierra Foothills
My gen 2 car just threw a cat efficiency code over the weekend. It had been sitting for a while without being driven (about 2 months). I took it for a long drive and after an hour we stopped for lunch. After lunch it was fine until I got on the freeway, then it posted the code. I had just filled it up with Chevron so I kept driving it and got the cats good and hot going up a long grade in 4th gear at WOT. After 2 more starts it cleared itself. She only has 107K miles. I'm guessing gunk in the cat just needed to burn off. Thoughts?
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My gen 2 car just threw a cat efficiency code over the weekend. It had been sitting for a while without being driven (about 2 months). I took it for a long drive and after an hour we stopped for lunch. After lunch it was fine until I got on the freeway, then it posted the code. I had just filled it up with Chevron so I kept driving it and got the cats good and hot going up a long grade in 4th gear at WOT. After 2 more starts it cleared itself. She only has 107K miles. I'm guessing gunk in the cat just needed to burn off. Thoughts?
FWIW, since Covid created less frequent driving, the stable of friends and neighbors for whose cars I wrench on has had a lot more trouble with bothersome codes that come and go.