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Discussion Starter · #1 ·
This seems like a really straightforward thing, so I feel dumb asking this question, but I couldn't find an answer after searching.

Where do I install the AEM UEGO O2 sensor if I still have the stock downpipe?

I've got a HFC that has a bung on it for the rear O2 sensor, and I'm assuming the stock downpipe only has a bung on it for the stock O2 sensor, so where am I supposed to put the UEGO O2 sensor? Does the stock front O2 sensor get replaced with the UEGO O2 sensor and then provide "stock-like" O2 level readings for the ECU? I know I don't want the UEGO after the HFC, so the rear O2 bung is out of the question.
 

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Discussion Starter · #5 ·
noob question what happens if he replaces the rear 02?
I'll get a CEL that sticks around even if I disable the rear O2 in the ECU. I'd like to not get a CEL (hence the HFC) plus it's not good to have your wideband O2 sensor after the cat. I'm sure you don't want the stock front sensor there either, so there's really nothing to do with that bunghole (heh) except keep the rear O2 sensor there.
 

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Discussion Starter · #9 ·

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You can weld it on the down pipe. Or upgrade to a DP with an extra bung already welded into it. I think the AMS DP has a second one already welded on.
 

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get a bung welded before the cat. if u drill into the cat make sure the bung is SS. But i would just weld it to the dp Make sure the bung is in a location that doesnt interfere with the flow of the air going to the first 02 sensor.
 

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Discussion Starter · #20 ·
This would have been a lot easier if Cobb had moved the HFC three inches back from the flange. I understand that they wanted to have the cat as close to the turbo as possible, and they probably assumed people would just buy their dp and put the bung there, but for me it's a bit inconvenient. Oh well, no big deal.
 
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