[ejacob363]

I have an issue with my 2012 335is that has stumped me for the better part of a year, and I can't find anyone else with an identical problem. The car runs the Stage 2+ MHD V10 OTS map and has 55,000 miles.

When running the car on E50 during a 3rd gear pull, the HPFP rail pressure crashes between 3000–4000 RPM and recovers higher in the rev range. In line with the drop in rail pressure are almost max negative STFT. This is frequently followed by various misfire codes and 29DC (cylinder injection cutout). There are no codes/misfires if I start in 2nd and shift into 3rd, but there are still large negative STFTs. On 93 oct., there is no decline in HPFP pressure or any codes/misfires, but the negative STFT remains, and there appear to be several timing corrections. In all cases, the LPFP seems to be keeping sufficient pressure.

My current assumption is that the O2 sensors are bad or that I have another faulty sensor someplace (either on the fuel or intake side), but I am far from an expert at deciphering datalogs. I was hoping someone could interpret what this could mean, or if you've had anything similar happen, I'd appreciate any input.


Relevant maintenance:
OEM HPFP – 1000 miles ago
Index 12 Injectors – 2000 miles ago
Walnut Blast – 2000 miles ago
LPFP (Fuel-It! Stage 2) – 3000 miles ago
NGK 2-step plugs – 8,000 miles ago
Eldor coils – 8,000 miles ago


Datalog for E50 3rd gear:
https://datazap.me/u/ejacob363/e50-3...-21-22&solo=19

Datalog for E50 2nd to 3rd:
https://datazap.me/u/ejacob363/e50-2...14-19-20-21-22

Datalog for 93 oct. 3rd gear:
https://datazap.me/u/ejacob363/93-oc...14-19-20-21-22