Uh, maybe it IS the O2 sensor...
 

Thought I'd swap over my O2 sensors to check if there was a problem with one. Pulled off first post cat. Hmm, think I found the problem. 😏http://986forum.com/forums/uploads01...1408225066.jpg

wow looks like the shield was burned/melted right off.

What symptoms were you seeing? O2 codes? Rough running?

I think I need to pull mine and check that as well.

Actually, it ran just fine. Had a CEL and the code was a p0430, which signals a bad cat ( or maybe a sensor that is toast). Also the Durametric readings for pre and post cat were both in roller coaster mode.

How many miles on this O2 sensor?

Don't know really. The car has 85k miles on it but I've only had it for a year or so. The O2 on bank 1 is clean.

Congrat's! Its always nice to find the exact cause of the problem on the first try!

I usually employ the "replaced-345-parts-and-its-still-not-fixed" approach. :)

Too funny. Sounds like someone I know!

Yep, sometimes they do get fouled. Now for the next big question: Why did that bank get so fouled with oil??

Actually, it is not really fouled with oil. The outer shell is broken/corroded/missing and is coated with carbon deposits. The inner sensor is faking off as well. Could be the result of the massive air leak due to a broken oil filler tube and the resulting backfiring and other small explosions that I heard. All fixed now. We'll see...

Those heavy carbon deposits look like excess burned oil in the exhaust to me... but I could be wrong.

Is that a oem or Bosche O2 ?

Not to mention a guaranteed performance improvement for your money spent!

Yes, you are probably right. I have replaced the sensor but the readings still indicate a cat problem. Marbe I'll try a smoke test on the exhaust to check for leaks. I changed the AOS in the spring and the MAF is fairly new as well. Hopefully it's not really the cat. Major $ !

If you end up needing a cat or cats I happen to know a guy that has both cats from my donor engine ;)

Hopefully I won't need them ( it ). All 4 cats ?


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Maybe pull and compare spark plugs on both banks. If one side is heavily carboned, you know there is oil in the combustion chamber.

so I bought a used cat on eBay for 120 bucks. Install no sweat. Running for a week and no codes yet. Probably too early to tell (touch wood) but my SAI codes haven't come back either. Wouldn't that be lovely! :)

Congrats:cheers: