Because in order for the PC to do it's job, you have to disable the feedback loop to prevend the ECU to undo the changes of the PC by correcting its signals based on the reading of the O2 sensor.
Does that make any sense? I'm confusing myself at the moment. I need to get in bed.
Yeah, that makes sense. But only for the current implementation of the Power Commander, IMO. I would think a
complete Power Commander solution would itself make use of the information from the O2 sensor. It's valuable to know what the composition of your exhaust gases is, and I'm not talking about keeping the comforter pulled over your head. The OEM design attempts to get the combustion right on the front end, then uses the O2 sensor to measure whether the mixture is
actually good. Clearly, Yammie doesn't think they can get combustion completely right without measuring the output. If they could, they'd ditch the O2 sensor and save some cost. Using the O2 sensor seems like a good strategy to me.
That's why I'm surprised the PCIII ditches this potentially valuable system input. Theoretically, the Power Commander could use such an input to verify that the programmed changes in the map actually do no harm.
Am I smoking crack?