Bad fuel trims, 2C2E but no check engine light

Benjiman

Lurker
May 2, 2021
20
4
0
Hi everyone, bit of a strange one here.
Did a second gear wot log the other day. Nothing really seemed strange during the pull, plus I hadn't done a wot pull since last year as the weather has been rubbish over the winter, so if it did lack a bit of power I may not have noticed.
The only thing I noticed was a weird smell about five minutes later when I got out the car, thought nothing of it and went home nice easy motorway drive for about an hour.

Once back I thought I'd check for any codes before looking at the log, I had a 2C2E code 'DME: Oxygen sensor 2 before catalytic converter: Coasting mode check'. I thought that was strange so had a look at the log, Bank 2 STFT seemed to be stuck at 0 and Bank 2 AFR was around 19-20! Could that high an AFR have caused any engine damage? Nothing came up on the dash and I'd never have even known about it unless I checked for codes and the log.

I cleared the code and it hasn't come back, I haven't done any wot pulls since however. I did two logs of a 15 minute drive, one from cold start the other warm.
In both 15 min drive logs STFTs and LTFTs look bad to me, AFR doesn't look too bad but I'm not sure if good enough?
In the WOT pull log both Low and High Fuel Pressures look good to me.
I initially suspected a dying O2 sensor but INPA shows the Voltages in range. Now thinking possible vacuum leak?
I'm hoping to someone more experienced something in the logs might stick out that I'm missing?

Am I safe to do another wot pull to get another log, also see if the error code comes back? The AFR is worrying to me but I'm no expert and don't fully understand it.

Thanks for reading.

Log from WOT pull;

Log from cold start 15 min drive;

Log from warm start 15 min drive;


2009 N54 DCT (UK)
XHP Stage 3
MHD Stage 2+
Inlets
Index 12
Walnut blasted
Direct Port WMI (but that is currently disabled)
 

Benjiman

Lurker
May 2, 2021
20
4
0
Quick update;

One of the o2 sensors was loose so I tightened it up. Now the problem has changed to bank 1 with a 2C2D code, exactly the same stft gets stuck at 0 and afr raises to around 20.

Thinking of replacing both pre cat sensors with new ones, don't really want to throw money at them if it could be something else though. Also seems quite strange that the same problem has switched from bank 2 to bank 1 with nothing done to the car other than tighten an o2 sensor.

Anyone have any ideas?