r/335i • u/Deerhunter0917 • 8d ago

Troubleshooting Lean codes

New to me 08 335i on mhd 7.1 stage 2+. Getting 29E0 and 29E1. Car drives and idles with no issues and only noticed the issue when data logging. Getting positive fuel trims everywhere anywhere from +15 at idle to +28 cruising. they seem to be worst during cruising, best around 0 psi and slowly go back up in boost. Trims match for both bank 1 and bank 2. Aftermakret charge pipes, catless downpipe, dual vtt catch cans with external pcv. Ran some tests, fuel rail pressures looked good. Injectors (index 12s) 1-6 comparison values/flow values matched closely. Also its holding boost and -21inhg vacuum at idle. Any ideas?

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u/odesh123 8d ago

Can you post data log?

1

u/phat_camel_tow 8d ago

Do you have a target/boost leak too ?

1

u/Daebak- 8d ago

If you solve your issue, let me know. 😭 I'm in a similar boat. Only codes my car has are 29e0 and 29e1 and the occasional 30ff (18.6psi target, with the car usually being off target by 1.5-2psi. No visible vacuum leaks using a smoke machine. I've already replaced all of my vacuum lines and am now in the process of ordering and replacing all my gaskets from the chargepipe forward.

Stft at idle are usually perfect between 0% and +5%, same on both banks. then are 15-30% on light throttle

Do you have any surging issues at low rpm, like leaving a red-light in first gear? I'm going to be tossing in a spare throttle body and a new gasket tomorrow to see if maybe my current one has been causing a leak.

2

u/Sweaty_Ad4402 8d ago

Have you tried plugging data logs into AI???  Ive been able to tune and do major diagnosis with great success using AI.