Quote:
Originally Posted by johnlvs2run
I'm not convinced the o2 sensor reading of .6 volts is indicative that Dfco is not working.
Why does instantaneous mpg show that Dfco is almost immediate?
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I understand your skepticism, and I believe there is a chance it turns out correct. But it seems unlikely. The UG probably shows 999 because the UG mpg reading is not based on a specific sensor, but is rather a calculation. So when I clicked the button on the UG saying my car has DFCO the unit began showing all those nines whenever I let go of the throttle for a second while in gear. They have programmed the UG to assume that there is not fuel. I don't think they took into account the variations I'm seeing. It'snot a scientific instrument. It's really just a very good consumer toy. So I guess I'm saying my hunch is that I should believe the voltage reading from my relatively new sensor rather than the UG's calculation. Don't forget that once I started using DFCO last spring, after three years of basically accurate calibration of the UG's fuel consumption calc to the gas station pump I use, I suddenly started getting FE data showing a big difference in FE. The UG was suddenly way off. Suddenly it was always telling me I had used a lot less fuel than my regular pump was saying I had. The O2 sensor data I'm seeing is the best explanation of that experience: that the UG's instant FE calc is imprecise for DFCO scenarios and exaggerates my car's effectiveness in cutting off the fuel.