I just wanted to make sure that it is the nbo2 sensors that, as you said, serve as a witness to the MAF data and not the other way around.
Correct me if I'm wrong, but our cars will still operate with the maf disconnected, which is why I questioned that.
You don't happen to know the trigger/threshold voltages on the nbo2 sensor readout that actually causes the fueling changes, do you? I've studied the different voltage vs AFR plots and the curve's temperature dependence, but I haven't been able to find any hard number about the ecu's thresholds for reversing the fuel trend.
The below pic came from a Bosch pdf, but they have inconveniently omitted the axis scales. The other chart is an actual plot, but no info on what sensor was used or at what temp. My best to guess is .7 and .25 are the thresholds based on overlaying trust two charts.
Can you guess why a tinkerer such as my self would be interested in this info? I'll give you a hint, there's more power at 14.2 than there is at 14.7
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