C6 Corvette flex fuel setup

[Scottgt21]

I had my car running pretty good on 91 pump gas so I decided to try to set it up on a flex fuel tune. Made myself a little base map to start off on and threw 5 gallons of E85 into about a half tank of gas. Started up no problem and idle is sitting pretty much around 1 lambda. Odd thing is that according to my scanner it says im about 20% lean at idle and cruising around. The car drives pretty smooth minus a bit of surge at low rpm from time to time but I'll work that out a little later. This is my first time attempting a flex fuel tune and I've gone through everything I thought was relevant. I'll attach my tune and a log file from this afternoon. Do any of you guys see something amiss as I'm sure I've overlooked a few things or set something up incorrectly. Thanks for any helpMy gs 2bar (flex fuel).hptMy gs flex fuel 1(first drive).hpl

[07GTS]

ecm330 enable it, also comp change thresh 2% and maby a .04 in the other transition/delay so it uses whats in the rails, disable desoot mode also, for flex the blend factors for the transient fuel needs to be populated so it adjusts for ethanol, few little things that jump out

[Scottgt21]

Right on I appreciate the suggestions. I'll look into those now

[Scottgt21]

ecm330 enable it, also comp change thresh 2% and maby a .04 in the other transition/delay so it uses whats in the rails, disable desoot mode also, for flex the blend factors for the transient fuel needs to be populated so it adjusts for ethanol, few little things that jump out

I think I've got all the changes made that you suggested. How does this look?

[07GTS]

ecm33392 can be set to 1.0 also will help dialing in fuel without chasing a moving target, the evap blend just same as impact, then looks good just dial it in

[Scottgt21]

ecm33392 can be set to 1.0 also will help dialing in fuel without chasing a moving target, the evap blend just same as impact, then looks good just dial it in

Thanks for the pointers. I've made those changes and I'll see how the car responds this weekend when I have some free time. When you say to just dial it in, do you mean with the MAF and VE tables? I was under the assumption that when tuning flex fuel you shouldn't need to adjust those much. If it needs just a little fine tuning then no biggie but, if I need to make big changes to those tables I.E around 20% am I still missing something or is that kinda normal?

[07GTS]

yes mainly because if u set the multiplier table to 1.0 for airflow which i recommended it would have added various percentages to your fueling based on different airflow aside from the normal maf/vve so with it at 1.0 now u should check the maf/vve make sure they are ok and more then likely may need a few tweaks to get back to normal but should be better overall like that for the flex percentages and be more consistent

[Scottgt21]

yes mainly because if u set the multiplier table to 1.0 for airflow which i recommended it would have added various percentages to your fueling based on different airflow aside from the normal maf/vve so with it at 1.0 now u should check the maf/vve make sure they are ok and more then likely may need a few tweaks to get back to normal but should be better overall like that for the flex percentages and be more consistent

Thank you for all the tips. Today I found that my Math that I'd set up my wideband error histogram with was not set up correctly to read EQ ratio instead of AFR which were skewing the numbers. But with you tips applied the car is transitioning very nicely as I add more E85. Fueling is staying about spot on and timing is following my flex adder as well.