So started reading the gasbuddy message forums, seem's 99% of the stations I frequent have been selling E10 w/o labeling it on the pumps or stations. So I went to a known 100% gas station on my last tank, and even tho temp's soared into the mid 90's requiring alot more AC usage, even some non-Ecno AC on a few days, my last 6 tanks avg'd 27.6mpg (much cooler days, never had to turn on max AC) my first tank avg's 29.6. So what, big deal 2mpg's (what about a 7% increase). Well when paying the (or near) same price I'm actually saving money by paying more. Using those figures, a 27.6mpg tank for 350miles cost $46.29 @3.65e10 to fill, and at 29.6mpg only $44.81 @3.79(100%), so it's less than a $1.50, but every tank, that adds up! (probably doing my math wrong going by miles vs gallons)

So to my question, is there a faster way to reset the computer from thinking it's running E10 to pure gas? I thought I read somwere it takes at least 3 tanks, my first took 2 weeks, if these high temps continue I would like to try to reap the savings faster if possible.

 

There is a recent study http://www.ethanol.org/pdf/contentmg...yStudy_001.pdf

comparing 87 octane with E10, E20 and E30 blends. The results may be surprising to many readers. This reply doesn't answer your question but might E10 might be the worse fuel for mileage and your pocketbook.

 

You may be remembering GaryG talking about it took him/takes 3 tanks of fuel to reobtain his previous vehicle mileage after using one tank of E10. Our Escape Hybrid does not have a "reset" computer button in regards to mpg and ethanol useage.

 

The car keeps trim values for numerous air-fuel mixtures under numerous load and RPM values. It takes GaryG 3 tanks to get his car back to what he considers normal. The time will vary from person to person.

Let's simplify the data for this discussion to include only a few values:

The car learns fuel trim at:

1000 rpm and 30% load
1000 rpm and 40% load
1000 rpm and 50% load
1000 rpm and 90% load
1000 rpm and 99% load

1100 rpm and 30% load
1100 rpm and 40% load etc.... etc..

You get the picture. The car keeps fuel trim values for thousands of RPM and Load conditions. It might take 3 tanks for someone to cycle through all combinations when they change ethanol %.

Drive at constant speed and say 2400 RPM on the highway, then change fuel.
Then get back on the highway at the same speed and RPM.
The FEH will adjust for this particular condition (2400 RPM) within minutes.
But it won't have a chance to correct for all the other conditions until you vary the RPM and load conditions. So in theory, stop and go city will correct your fuel trim the quickest, because you vary the throttle a lot, and highway driving will take the longest.

-John