The thing is you don't need to change your wideband settings. You were already on the right path with the AFR base change. That is how GM does it with the flex fuel vehicles. You have to read the wideband as if it were on gas still. 9.76:1 is the same as 14.7:1 on gas and that is how the wideband will show it. You just have to do the conversion yourself. The problem is the 20% theory is a bit light, but a good start.

 

OK, so the ECM will base the enrichment EQ's from the 9.76:1 stoich AFR entered into the stoich AFR block? Versus 14.7 like now? So then I tune with the wideband just like i did with gas, look for 14.7 when commanded and my pe ratio when commanded?

 

Good to know!

I did not know that and often wondered about the WBO2 readings when running meth.

 

Yeah, I think we're on the same page. I'll post an example from some E85 logs I have when I get home from work.

 

Here are a few examples. Now these are actual factory flex fuel vehicles. Having taken the few minutes to look at them I see that my truck is actually a bit off on the AFR meaning that it is likely a bit rich on either the V.E. or the maf calibration. I've barely touched it since the initial dial in from the cam swap. My truck is an 06' and uses software to guess the Ethanol content. My 02' Tahoe actually has the sensor in the fuel line to detect Ethanol content. Somehow in the truck log posted there I accidently deleted the map from the log, but it is my most recent log from the truck. I run E85 only in both vehicles unless I am where I don't have the choice. All of that aside you can see the AFR commanded numbers. The system is basicly adjusting this number to match what the AFR should be if it were running gas only. On true E85 a commanded AFR of around 9.7:1 should read the same on a wideband or narrowband sensor as 14.7:1 on true 100% gas (not a 10/90 blend like is common at the pumps). Don't look at the number on the wideband as 14.7:1, but mearly 1.0:1 Lambada. Think Matrix... lol

 

Ok, with my gas VE tables in effect, and 9.7:1 stoich, I am running 12.2:1 on the wideband. This makes no sense to me, shouldnt it be lean? When I change my Stoich AFR to 14.7 it changes the wideband to 16.4:1, this sounds better to me??

 

This would be a good time to test your E85 Ethanol content just to make sure it's the correct mix. Kinda sounds like you have too high of a gas content in there.