have a little debate. damon says the higher the voltage reading the leaner the mixture. i say the higher the voltage reading the richer the mixture is. now to support my claim, both my OTC scanners have a led that switches from lean to rich when the 02 go above .5 volts. now unless scanners have been programmed wrong or my teaching is incorrect, the higher the voltage the more unburned fuel is in the exhaust. then the computer reduces the pulse width to lean the mixture. maybe i'm wrong, but i don't think so.

 

The higher the voltage, the less O2 in the exhaust due to a richer mixture. The lower the voltage, the more O2 in the exhaust due to a leaner mixture.

FYI, with Highway Mode invoked, I run a "commanded" AF ratio of around 16.4-17:1 and my O2 mV readings are around 60-120 mV.

 

thank you. that's one for me.