Help with OFT just switched E85 - LTFT help needed
 

Hi, I just switched to e85 through OFT a few days ago, been logging. I noticed my LTFT on 91 was fine under +5 usually. Now since I switched to e85 the LTFT varies a lot more from -3 to -5 idle and usually -10 under regular throttle. I have 2 logs 1 with 91 and 1 with e85 hope someone that knows more then me can take a look.

all 3rd gear pulls in 85-90F ambient, low humidity I have UEL headers, test pipe catback w/ resonator right now. Drop in K&N filter w/ silicone sleeve.

91 - stage2 brz UEL headers
http://www.datazap.me/u/hyped23/2013...=2&data=1-2-11

e85 - stage2 brz UEL headers
http://www.datazap.me/u/hyped23/e850...=0&data=1-2-11

Let me know what you think, I'm not sure if just bad e85 or maybe a exhaust leak? If you have time look at the rest of the log paramaters as well. but I went from around +2 LTFT on 91 to -10 on e85...? :iono:

Thanks - Alex

edit* I just installed headers a few days ago, all new gaskets torqued all. Then ran 91 seemed great and switched to e85 once I ran low did everything properly but it all happened in only a few day time span. I added roughly a gal of 91 just to see, and LTFT seemed to drop to -8(very low throttle), but now going back up over -10 to -13 (mid throttle) with more driving.

You have that backwards.

so most likely it is just low ethanol then?

Most likely low ethanol content. I switched over to e85 with just under 1/4 tank of 93 in there (Not recommended). Have the same LTFT -5 to -12 when cruising. It's slowly fixing itself as the 93 is replaced with more e85. As long as there isn't knock it shouldn't be much of an issue. It can compensate up to 40% so you're not even close to the fuel trim limit.

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You should see your LTFT even out over your next couple fill-ups. Residual petrol lowers E%.

Thanks for the info, I think its probably just really low e% then, I can try to source some other places but there is not a lot of e85 in my area.

Yea, but when I switched to e85 I was on E extremely low I run the car vew low until it started to hesitate then filled up. This log was at about 1/2 tank so I think there was not a lot of residual 91 left but idk. I guess I just have to try different stations or roll with it for a while.

I think I messed up by adding a gal of 91, now LTFT seems even higher -13 to -14 but havnt logged to confirm. I just wanted to see what happens, but I think I will siphon this out and start over.

When the fuel light comes on you've got ~3 gallons left in the tank. Run Torque to get a more accurate fuel level reading, and you can run it down even further.

Yeah I know, I ran out of gas a few times lol. I didn't swap fuel once I was on E on the dash, what I did was once I was on E I drove around for a while, then started driving around close to gas station, didn't fill up until my car started to hesitate / lose throttle response. I know its improbable to run out 100% fuel but I'm confident I got most of it out before switch.

I'm not familiar with torque? I'm still new to OFT and e85, I have minor experience with other tuning systems and 91/100 oct fuel mostly

***Now that the LTFT is getting as high as -15% under minor load what should I do?? would switching to 91 map do anything.
What would happen if I added 100 octane gas, would this be bad?

I'm running on -7 LTFT for the longest time, and as long as it doesn't get TOO low, apparently you should be ok. It's just the ethanol content from the pump that's too low. Definitely not e85 as they advertise here in AZ. More like what? E60 maybe

When you are on E85 the LTFT are less of a concern than on 91 or 93. OFT allows the LTFT to make up for variances in ethanol concentrations rather than a flexfuel setup. By the time you run another 2 tanks of your local E85 through the car things will have stabilised.

yeah las vegas sucks so far. I seen one pump that advertises anywhere from 50-80% ethanol that's huge variance. The one I bought from says 85%E but no fukn way the fuel trims seem way off. It got worse by adding in gal/91 so I wouldn't recommend anyone do that.

Thanks for the info, Ill try to stick with it for a while. it seems theres just not any quality e85 in my area. If that's the case ill switch back to 91, Id prefer to run quality 91 with better gas milage then e50. maybe ill have some tested.

Somewhere on the forums Shiv has mentioned there is no power difference from E65 and up.