O2 Swing Points

[EagleMark]

I found some conflicting info on O2 swing pints in searches. Starts with this:

Table {B4105} “O2 Switch Point”:
Set all values to 450mv. This value (450mv) equates to 14.7 AFR and has
been found to enhance the smoothness and the accuracy of the LTFTBEN
values.

Thought the .450 was Stoich and not 14.7 to 1 AFR?

If changing AFR to fuel of say E10 which is 14.2 then Stoich would be the same .450 mv, that is what we're shooting for correct? Stoich?

There's a very small window of accuracy in narrow band O2 sensors which .450 is right in the middle of. So this was my next point of conflict"

The O2 switch points are basically the voltage the computer will switch around while in Closed Loop. So if you want a leaner or richer AFR then adjust your switch points accordingly. I have mine set to switch around ~15.2-15.5 while in a light load, which in my case is ~ 250mV. It is good for a couple more MPG.

Since this is outside of accuracy of NB it could not be accurate, but if set with WB could it work?

[Gregs]

I found some conflicting info on O2 swing pints in searches. Starts with this:



Thought the .450 was Stoich and not 14.7 to 1 AFR?

If changing AFR to fuel of say E10 which is 14.2 then Stoich would be the same .450 mv, that is what we're shooting for correct? Stoich?

There's a very small window of accuracy in narrow band O2 sensors which .450 is right in the middle of. So this was my next point of conflict"



Since this is outside of accuracy of NB it could not be accurate, but if set with WB could it work?

http://forum.efilive.com/showthread....&highlight=e10

^^ its kind of a long read...

[EagleMark]

Yes long read and a good read! And through all that, seaching the internet for correct AFR for E10 to determine Lamda I came up with 13.81 to 14.3 for E10 fuel. Seems the number preferred on this forum is 14.22 which is where I started my tune.

Data logging serial WB shows average lambda of .98 and a AFR of 13.9 when comanded AFR is set to 14.22

Closest correct answer to AFR for E10 came from GMPP back in 2009 at 13.81.
http://forum.efilive.com/showthread....l=1#post103066

Since our pumps here state fuel can contain up to 10% ethenol it's a wonder what it will be. So far my summer through winter has yeilded same consistent 13.9 in E10 fuel supply.

Last summer I did 2 tanks of 93 non ethonal for highway trips, first tank had a little E10 and yeilded 14.4 and second tank was 14.6

Many years ago I drove a tanker truck and delivered fuel to gas stations (pre E fuel) do to always leaving with a full tank and severel fuels in seperate compartments and the gas station order to take a full load but may have not sold enough gas by the time of delivery it may not fit! Rule then was 92-3 octane could go in 83-4 octane tank but not the other way around. This was always the case as less 93 octane was sold. Intresting note is tanker could have load of gas delivered, then load of diesel, then load of gas. Same tanks, no flush or wash.

So I asked a fuel delivery driver what the rules are now? Absolutly no E fuel in Non Ethonal tanks. But you can do anything you need to do with all three E fuel octanes but try to only put higher octane to lower octane tank if you have to much. He also stated all octanes contain same amount of ethanol. We have no E15 or E85 in our area...