So this morning there was some traffic so I didn't get any constant highway cruise readings, and after poking through my old logs I realized the data there wasn't actually clean either :/ I'll be taking a longer drive tomorrow and logging both stock and modified VVT map tunes on flat (hopefully) open freeway and figure out what's really going on.
I've been trying to think of a way to outsmart the rear O2 sensor but I just found out it's a narrowband, which means it'll be 200 bucks for a narrowband emulator to trick it :/ The other thing I could do is set the A/F learning mass airflow limit higher to basically disable the downstream sensor. There's a value called "Max range B/Min range C" which is set at 12g/s, which I think if I bump up to 17 will avoid learning because highway cruising uses about 16
However, there's a "Max range C/Min range D" value of 20 which I'm too scared to touch.
I could also outright disable learning by setting learning limits to 0%, but that makes me feel uncomfortable too.
These new ECUs are too smart! Slightly older models could either be commanded to run lean in open loop, or tricked into it by triggering open loop -_- I suppose I could set a majority of the 14.7 cells to 14.6 to trigger open loop everywhere but I would literally have to disable closed loop operation everywhere or else it starts learning again, and I don't really feel comfortable having it run open loop everywhere except idle.