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Author Topic: MED9.1 VR6 cat delete, rich until warm  (Read 1763 times)
MirXas
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« on: July 16, 2023, 10:12:03 AM »

Hey.
MED 9.1 3.2 FSI VR6 swapped A3 8L. Cats removed, rear 02's in place. Set CDKAT, CDKATSP to disable cat dtc's and FKHABMN, FHOKH to disable kat heating. When front o2's start working, lambda correction is -25% on both banks until about ~82 degrees of engine temperature in normal units. Then it goes to normal trims and starts fluctuating +-10% for some time (checking rear o2's I guess, because they respond to that). No fault codes until some driving on cold engine, then both bank fuel trim rich codes appear. Everything was fine before removing both cats. Any ideas what could be causing this behavior and what should I modify next ?
« Last Edit: July 16, 2023, 10:38:43 AM by MirXas » Logged
VagDoc
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« Reply #1 on: July 16, 2023, 02:48:05 PM »

Disable the rear sensors and cats in ESKONF+Prokon and leave the cat heating maps alone.
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_nameless
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« Reply #2 on: July 16, 2023, 07:16:42 PM »

Disable the rear sensors and cats in ESKONF+Prokon and leave the cat heating maps alone.
Hey doc... MED9 has no ESKONF
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Giving your mom a tuneup
VagDoc
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« Reply #3 on: July 16, 2023, 11:43:44 PM »

You are correct lol I am not entirely sure why I said that because I know it doesn't exist in MED9. Cheesy
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MirXas
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« Reply #4 on: July 17, 2023, 08:52:06 AM »

Yup, there's no eskonf. No ideas ? Smiley I can log something with vcds, just dont know what.
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Silencesilja
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« Reply #5 on: July 17, 2023, 01:31:34 PM »

Try leaving everything stock, except FHOKH, rise RLKTDMN to max, and lower RLKTDMX to min.. Might not be the best solution since cat cleaning and post cat corrections will still work, I don't know the other abbreviations off the top of my head
« Last Edit: July 17, 2023, 01:34:45 PM by Silencesilja » Logged
Leonhard
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« Reply #6 on: July 17, 2023, 11:19:26 PM »

you might add:

CWKONABG = 1 reduced to bit 0 (B_katfz)

and there is no need for working rear O2s

CWKONLS = 17 (bit 0 + 4) only B_lsv(1+2) activ
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MirXas
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« Reply #7 on: August 07, 2023, 04:09:24 AM »

Still no luck unfortunately. Looks almost like a mechanical/fuel delivery problem, but i'm positive that it was fine before removing cat's. Tried completely disabling and removing rear o2's (as much codewords etc. that i could find in s4wiki and elsewhere). Disconnecting the MAF does nothing. Almost thinking of trying to tune fueling maps, but I guess that wont work if fueling is in some other "state" than normal. And yes, I dont know what i'm talking about Cheesy
« Last Edit: August 07, 2023, 05:00:35 AM by MirXas » Logged
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