Stioichiometric AFR straight across the board?

[Protec]

Looking for your recommendations on if you change the B3671 Stoich AFR from the GM scale to a straight number such as 14.2 for those of us who have somewhere between E7 and E10?

What advantages does this have?


The vehicle does not have a flex fuel sensor but I assume you leave B0178 Flex Fuel option as "Yes" and B0178 as "Calculated" and it should use LFTF's????

It would seem that with 14.2 is across the board the LFTS's would not matter as it would always command 14.2?

Is this a better process than the PCM trying to use the different Stoich values in the factory setup?


Thanks in advance..

j

[joecar]

If your PCM calculates the stoich AFR (using LTFT"s) then by setting B3671 to a single value you'll short circuit the process, which will give you the wrong stoich AFR since the alcohol content of E10 is +/-5%...

i.e. my opinion is that the factory table/algorithm work reasonably well.


Which year/model/vehicle do you have...?

[Protec]

14569


Joe,

Its a 2009 L9H 6.2L that was a swap into a 2011 Jeep Jk - Sorry :)


This was a change done when I had it tuned professionally... The truck runs fine and WB02 are where they should be...

I'm just getting to a point where I'm looking to know "Why" some things are the way they are... You know.. Just enough information to be dangerous!


Thanks for any help...


John

[joecar]

Your tuner may understand the local fuel in your area.

[Protec]

Thanks Joe...

I'll speak with him on some background on this method..

Appreciate you...

Thanks,

John