liquid_helix136

I noticed if you turn off the primary o2 sensor, (aka run it in open loop) then go back to closed loop, the fueling is entirely f@#ked, like you mentioned. It does it with closed loop enabled, but set to 0/0 as well huh? That's highly annoying.

VitViper

It's not as bad with 0/0, but there is some sort of fail safe condition triggered. When the primary lambda is off you are absolutely in silent "limp mode" logic. Everything appears to work and run just fine til you turn it back on. I've found quite a few gotchas like this in the Honda ECU's over the years, some quite useful for some things lol. I just don't care to share -- my work gets ripped off enough as it is, heh.

liquid_helix136

Fair enough.

Just wanted to update, I went ahead and spent about an hour tuning the fuel tables with closed loop activated and S.Trim set to -1/+1%, this seemed to be close enough to 0% that I could use the values as raw fuel values, and it didn't trigger the fail safe mode. Put closed loop back on to -10/+10% and drove around for about 30 minutes and now the learned S.Trim value is only taking away 1% fuel on shifts. I'm seeing closed loop correct for at most 4% on my logs. Looks decent