Hey Captain, I have a question I have been torturing myself with.

Can you please describe exactly how the PCM uses the MAF signal?

Here's my questions. If the MAF gave slightly wrong signal for the amount of air entering the engine, then I assume PCM would attempt to add the factory calibrated amount of fuel for that skewed amount of air. Then when the O2 sensor sees a slightly wrong signal (rich or lean) as a result, the PCM would add or subtract fuel based on the O2 sensor values? Can an out of calibrated MAF present as skewed fuel trims? Am I thinking about this in the correct way?

My MAF reads 5.5g/sec at 575 RPM. A little high from a spec that you previously gave. I also see the fuel trim is supposedly correcting from a supposedly slightly rich condition at idle. Trying to understand if this observation is directly related to my MAF calibration.

Does it make sense to verify MAF calibration before putting too much stock in fuel trim values?

 

This one has just the right amount of technical stuff, while still explaining how and why it works: