Can someone help me understand lean burn a little better?
 

I understand it lowers A/F ratio but what exactly should I be looking for on the o2 sensor? I was told by some people the voltage will drop to 0.000 when in L/B but then a read another post that said 0.035-0.075 was L/B? Which one is true? The reason I ask is, if it is 0.000 then L/B is extremely hard to get to engage on my civic, if it's 0.035-0.075 then I'm in luck because it's extremely easy to get into L/B.

I'm also talking about maximum L/B. I know that the lower the a/F the lower the Voltage but I'm talking about the lowest af ratio possible.

Nobody? :(

You can't reliably detect the A/F away from stoichiometric on a narrowband sensor. You need a wideband.

On a normal engine I think you can't really go much past 20:1 without having problems igniting the fuel.

I'm talking about my civic HX. 5-wire o2 sensor that's wideband right?

Yes, but the ecu may not be.
http://ecomodder.com/forum/showthrea...deo-28496.html
The SGII Xgauge Database - CleanMPG Forums

Do you suddenly see an mpg jump on the ultra gauge? My ultra gauge shows 0.000 when im in lean burn. Most likely it is the same on your car. You have to really learn how to get it. What does your gauge read when you are decelerating in 5 gear? Try driving at around 40 mph on a road, let your foot most of the way off the gas pedal but not all the way. What does it voltage does it say then?

No matter how light I go on the throttle it will read 0.035 or 0.050. And I don't see an mpg jump, UG can't detect L/B.

It might honestly be the fact that it hasn't had a tune up in probably 100k+ miles and the egr probably needs a good cleaning, along with an oil change, spark plugs etc etc. There is 198k on the car and I doubt the spark plugs or wires have ever been changed.

Study this picture:

http://chp.decc.gov.uk/cms/assets/im...R082FigC15.gif

I don't understand, what am I looking at exactly?

This is emissions correct? This doesn't display the voltage or any of the info I need :/.