
Originally Posted by
donald7150
I did not
Changing those values seems to have no effect on anything
Basically what happened was I bootlegged a tune that someone foolishly posted on this forum from a vendor i wont mention, I foolishly copied all the relevant values into my file and started using it. The truck behaved beautifully aside from cruising at highway speed entering a moderate grade i would get a P0299 underboost and limp mode.
If i floored it at every hill it was absolutely fine (definitely not ideal)
So I returned the stock boost control tables to my tune and all has been well for about 12,000km now and still the full effects of the tune
Boost control tables are just vane position and while they do control the boost, it has to line up with the boost setpoint tables as well. If the vanes are not spinning the turbo enough to reach the target in the boost setpoint table then that may cause the issue. I didnt experiment with it
The tune i have would command the vanes at around 70% at cruising speed/throttle position (im guessing in an effort to gain some MPGs) and i guess wasnt producing the boost pressure the ecu was expecting and threw the code every single time. Stock table has them at 85-90% in that same range. Once i went back to stock on those particular tables the underboost issue was gone
Ive learned alot since the original post and that tune i downloaded was definitely not a good one.