Plz Help With Tune, Fluctuating AFR

FlashPro questions & answers specific to the 2006-2011 Americas Civic Si
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d21x
Posts: 3
Joined: Thu Apr 14, 2022 4:51 pm

Plz Help With Tune, Fluctuating AFR

Post by d21x »

Hi,

2007 FA5
Ktuned 3" CAI
93 Octane
Stock Everything Else

Cruising at 70mph, my afr fluctuates. This is on cruise control. Also noticed when crusing and giving very light throttle afr fluctuates. Any help would be appreciated. Thanks.
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EFICU
Posts: 3299
Joined: Mon Feb 25, 2019 10:14 pm

Re: Plz Help With Tune, Fluctuating AFR

Post by EFICU »

Which calibration did you originally start with? I know that it's one of mine, but which one was the original because something has been modified to make the commanded AFR hunt. My AFR would be constant at part throttle, but yours is hunting while driving in part throttle instead of commanding 14.64. Let me know so I can compare the files.
d21x
Posts: 3
Joined: Thu Apr 14, 2022 4:51 pm

Re: Plz Help With Tune, Fluctuating AFR

Post by d21x »

Yes I did start with one of yours. Thank you by the way.

GoldeunAgma.SD.Rev01 (Blended)(Vtec4600)

This one had almost the same mod as mine so I used it and adjusted fuel.
EFICU
Posts: 3299
Joined: Mon Feb 25, 2019 10:14 pm

Re: Plz Help With Tune, Fluctuating AFR

Post by EFICU »

Gotcha. Comparison shows the only thing you changed was some fuel stuff, and you enabled the rear o2 sensor. Enabling the rear o2 sensor can cause some weird AFR issues. I would take the same calibration you posted here, your Rev5, disable the rear o2 sensor and make another datalog similar to the one you posted and see if the issue persists. If it goes away, we know the issue, if it still persists, then I can work with you starting on another calibration to diagnose the issue. But take your Rev5, uncheck the rear o2 sensor, save it as a new file, then reinspect and let me know.
d21x
Posts: 3
Joined: Thu Apr 14, 2022 4:51 pm

Re: Plz Help With Tune, Fluctuating AFR

Post by d21x »

Thanks for the fast response. I will do that. I guess I really only need the rear o2 for emissions, but since I don't need an inspection any time soon I'll just disable it. Thanks again!
EFICU
Posts: 3299
Joined: Mon Feb 25, 2019 10:14 pm

Re: Plz Help With Tune, Fluctuating AFR

Post by EFICU »

Yeah give it a shot and see how it acts. You will want to watch the commanded AFR, if the commanded AFR is constantly changing while you're cruising or at part throttle, something isn't right. It should command 14.64 at cruising and part throttle. The file you're on should be doing that, but I think the rear o2 being on is causing the hunting which is probably what is causing your issue you mention. But give it a shot, and post a datalog when you can. For inspection, you can have the calibration with it turned on.

You're welcome, let me know if it works, I'm curious to see.
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