[JoshApple]

So I am installing new turbos on my N54 335i 07, and when I removed my downpipes to start, I realized all my o2 sensors were completely black, one of them being completely fried and deformed. I also know that my catalytic converters blew a while back for some reason that I am not aware of.

There was a botched stage 1 tune that got corrupted and I had to have the ecu manually reset to stock at an Indy shop. It was causing all sorts of problems and maybe could have led to a jacked up fuel mixture?

I’m going to attach some pictures showing the black soot that is on the turbo exhaust holes or whatever on the engine block, keep in mind, that same black soot is current going into the exhaust system as well, in the downpipes and in the midpipes.

I’ll also attach the photos of the blown primary cats and the o2 sensor that is deformed.

I would like to get any idea as to what could cause this black soot and where I should go from here as I already have the car taken apart mostly

[neilvan]

Black soot is normal in the exhaust path as it is combustion; turbo more so.

The blown out cat and O2 are more serious; likely the tune related

[alpnwss]

Are your injectors toast? Might be running rich/lean

[JoshApple]

Originally Posted by alpnwss

Are your injectors toast? Might be running rich/lean

Not that I know of, no injector codes or rich lean codes. Replaced injectors to all index 12 shortly after I bought the car, don't think that's the issue but maybe I should check?

I have FCP lifetime warranty on all 6 so.

[nsjames]

you had a terrible tune that got the cats hot enough to melt.

Probably what destroyed that O2 sensor too.

Tune is fixed, soot is normal. Continue on.

[JoshApple]

Originally Posted by nsjames

you had a terrible tune that got the cats hot enough to melt.

Probably what destroyed that O2 sensor too.

Tune is fixed, soot is normal. Continue on.

Thanks a lot, most likely what happened

Catless downpipes going in as well as a new o2 sensor and we should be ready to go

[alpnwss]

Originally Posted by JoshApple

Not that I know of, no injector codes or rich lean codes. Replaced injectors to all index 12 shortly after I bought the car, don't think that's the issue but maybe I should check?

I have FCP lifetime warranty on all 6 so.

I was expecting your answer to be "I haven't touched the injectors, should I?"
If they're Index-12 and functioning properly they are not the culprit. Someone recently posted about a similar issue and had bad injectors. Sorry!