[e46m3to335i]

Can't figure out why I have this code. Started after I flashed from stock to MHD Stage 1 about a month ago. Since then I have changed plugs(NGK 1 step colder @ .022), coils, index 12 injectors (coded properly through INPA, walnut blast, upgraded PCV valve (BMS), vacuum lines (Veracious Motorsports 3.5mm), and a new bank 1 pre cat o2 sensor. I am currently running stage 2 tune because I recently added kittlyless DP's.

Car: 2009 135i M6 with 123K Miles

Current mods: MHD Stage 2 (91 Oct), DCI's, Kittyless DP's, VFSF CP with Tial BOV (11 psi spring) 1/4" tap from the manifold mod.

I have noticed that my bank 1 stft's are always 6-7 points higher than bank 2 always are. This code was present prior to the DP's and will always reappear with 20-30 miles of normal driving (usually while cruising on the highway).

Besides changing the bank 2 precat sensor along with both rear o2's, what else is there that could be throwing this code? Honestly the car drives amazing and idles extremely smooth. I've checked that both V-Band clamps are sealed and tightened correctly as well as the actual o2 sensors are snug in the pipes. Also confirmed that none of the sensors are located in the wrong pipes.

Any ideas??

-Nick

[RocketSurgeon]

Are you running dp fix? That's a common source of fuel trim issues.
Are the injectors 100% OEM, like from FCP or some reputable vendor?
Can you post up a log on datazap?

[e46m3to335i]

Originally Posted by RocketSurgeon

Are you running dp fix? That's a common source of fuel trim issues.
Are the injectors 100% OEM, like from FCP or some reputable vendor?
Can you post up a log on datazap?

No DP fix other than the catless option in the MHD tune options menu. Code was present prior to going catless as well. Injectors are genuine. I'll try to get a data log today and get it posted.

-Nick

[e46m3to335i]

https://datazap.me/u/e46m3to335i/log...og=0&data=3-21

[RocketSurgeon]

Have you tried clearing your adaptations?
Your bank 1 stft is higher despite bank 1 running a tad rich. I don't suppose there's a way to monitor post-cat O2 readings....

[e46m3to335i]

Originally Posted by RocketSurgeon

Have you tried clearing your adaptations?
Your bank 1 stft is higher despite bank 1 running a tad rich. I don't suppose there's a way to monitor post-cat O2 readings....

Yes. I have tried resetting adaptations multiple times. No change

[ArweenX1]

Originally Posted by e46m3to335i

Yes. I have tried resetting adaptations multiple times. No change

Had the same issues. Rear O2 replacement got rid of 2C31

[e46m3to335i]

Originally Posted by ArweenX1

Had the same issues. Rear O2 replacement got rid of 2C31

Did you replace both rear o2's at the same time or just bank 1?

[ArweenX1]

Originally Posted by e46m3to335i

Did you replace both rear o2's at the same time or just bank 1?

Both. Did upstream O2s a couple weeks before.

[e46m3to335i]

So I swung by an auto parts store after work yesterday and picked up a couple universal Bausch o2 sensors (Part# 15733). Cut off the factory o2 pigtails and made the appropriate connections with a solder gun. I think I found my issue, at least that's what my data logs are showing:

Prior to new rear o2's:

https://datazap.me/u/e46m3to335i/log...23&zoom=0-3720

After new o2's:

https://datazap.me/u/e46m3to335i/log...og=0&data=3-21