[flanmorrison]

Hi all - I'm attempting to diagnose an issue that has been ongoing for a few weeks. I am new to performance upgrades and tuning, so please forgive my ignorance.

2015 BMW M235i 8AT RWD
VRSF Intercooler
VRSF Chargepipe
Stage 1 BM3 (see below)

It started with a CEL for Mass Air Plausibility, Air Flow Too High. I cleared the code, it returned, and began to have a bit of a rough idle. The car was still under an extended warranty, so I took it in to get it diagnosed/fixed.

They replaced the MAF, and told me that it was likely bad due to an oiled K&N air filter that was installed by the previous owner. I ordered a Dinan intake and installed it, but a few days later the fault code returned, along with some rough idling (both on startup and when coasting to a stop) and the the car even stalled out (8AT transmission). This was followed by an additional fault code for lean mixture. At this point I was suspecting a vacuum leak.

I decided to take the vehicle to BMW to get a full diagnostic workup. They returned the car to me 10 days later, letting me know that they found no issues, they reset adaptations and the code hadn't returned.

An hour after I picked up the car, the CEL returned.

After a bit of research, I suspected that the combination of intake + intercooler was either sending more air than expected to the engine, or it was messing with the readings on the MAF sensor.

I was planning on tuning the car at a later point anyway, so I thought I'd try flashing BM3 Stage 1 tune to see if that might help adapt to the intake. Before I flashed, I took a few logs and saw a couple knocks and timing being pulled on WOT.

After the tune, no such timing issues or knowck. And so far the CEL hasn't returned, but upon reading the logs post-tune, I am seeing the following issues:
- lag in actual boost vs target (1-14 psig actual vs 16-17 target)
- unable to reach target load (70 actual vs 160 target)
- throttle angle spiking to 100 on deceleration without pedal input
- wastegate remaining at 100 while boost is building
- STFT remaining around 1.15 under load

I have taken the following troubleshooting steps:
- replaced MAF sensor twice
- triple checked all connections, tubes, seals
- sealed meth bung on chargepipe
- reset adaptations

LOGS

Stock
https://datazap.me/u/michael/stock-t...7-31&solo=1-31
https://datazap.me/u/michael/stock-t...0&solo=1-21-31
https://datazap.me/u/michael/stock-t...0&solo=1-21-31



BM3 Stage 1:
https://datazap.me/u/michael/bm3-sta...0&solo=1-21-31
https://datazap.me/u/michael/bm3-sta...0&solo=1-21-31

[mike@x-ph.com]

For a proper log, you need the acceleration pedal needs to be at 100% from 3000 rpm to redline