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Discussion Starter #1
I have a 2013 Civic.
I'm about to start experimenting with non ethanol Premium fuel to see if there's any fuel economy improvements.
For quicker results, should I reset the ECU, or just let it re-learn on it's own?
If reset is the answer, how exactly do I perform a reset so fuel & timing maps/trims are reset?
Thanks!
 

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I have a 2013 Civic.
I'm about to start experimenting with non ethanol Premium fuel to see if there's any fuel economy improvements.
For quicker results, should I reset the ECU, or just let it re-learn on it's own?
If reset is the answer, how exactly do I perform a reset so fuel & timing maps/trims are reset?
Thanks!
There are folks here that say they see a substantial increase in MPG by using premium fuel.
I did a premium fuel test on my '12EX auto trans and experienced minimal MPG increase.
6 tanks of 10 gal each, So California 91 octane.

I did not reset the PCM.
90% of driving is in the city
most trips less than 3 miles one way
most trips are from cold start (ambient) conditions.

As it is said: "your mileage may vary."
 

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I have a 2013 Civic.
I'm about to start experimenting with non ethanol Premium fuel to see if there's any fuel economy improvements.
For quicker results, should I reset the ECU, or just let it re-learn on it's own?
If reset is the answer, how exactly do I perform a reset so fuel & timing maps/trims are reset?
Thanks!
I've already tried that. Non-ethanol in any grade makes absolutely no difference in my Civic. In my VFR, non-ethanol makes it a completely different and more powerful vehicle.
 

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Hopefully Silver2Coupe will weigh in here, as well. He has done much experimentation in this realm and may be able to provide even more information.
 

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If you use a scan tool it will adjust faster but it should adjust on its own if you can make the ecu learn but on average it take a few tanks. Every time you add premium the octane raises in the tank from the regular and premium mix. Octane requirements change a lot too. The ecu is capable to adjust to 100 ron fuels with out a tune.Most major brand premium uses less ethanol or anther oxygenate. Too many variables to say if non ethanol gas will get better mpg.


Top Tier 3 Premium in my Honda's, I can get up to 30 to 40 percent better mpg and power is greater at lower rpms through the rpms I run at. I cant hypermile like I did in the past because traffic is so much worse and it is too dangerous to try even if its right or the law. The object is to use the Imid mpg and find the sweet spot for the octane you use, then see if you drive in that zone. Fuel enrichment is the ecu response to knock which will cause lower mpg but no knock.


Edit: Reset the ecu with a scan tool zeros the fuel trims and any learned throttle to trans settings. I used to do it in my 12 Civic which I got a best of 51 mpg average with premium and not exactly hypermiling. Average at the pump not Imid.
 

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Discussion Starter #8
So here's what happened so far.
Around town driving, nothing to report yet really. Day to day, my wife drives the car mostly and doesn't worry about mileage.
I drive if we're on a road trip, like we were yesterday....
100 km trip, no ac, 2 people in the car. Very mixed driving in warm weather, Half flat terrain, half hilly terrain with some 80 kmh stretches,100 kmh stretches, 3 towns, each with several stoplights, and one small city with about 30 or 40 stoplights, maybe half of which were red - again, hardly an ideal test, but I drove for mileage, eco on, traction off, and doing the speed limit.
51 US mpg - 61 Imperial.
I've never seen fuel economy that high in this car on 87. I got 50 US (60 imperial) once a few years ago on a really easy 80kmh 'mileage cruise'.
Not exactly scientific testing, but I know this car fairly well, and this is - definitely - a substantial improvement. This is at least 30% better economy than I've come to expect out of the car on a trip like that.
Testing will continue, but for now, non-ethanol 91 octane looks promising....
 

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That's why GM ( among others) lobbies to have a unified 95 octane fuel. Also, the Mazda Skyactiv engines that have 13:1 CFR in North America instead of 14:1 elsewehere, because our fuel sucks. The low octane fuel is a limitation in the quest for better fuel economy...

GM Lobbies For Standard 95 Octane Fuel | GM Authority

Marko!
 
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