Hi, I have a 2018 Sport 6MT with almost 40,000 miles on it and I’m wondering if anybody has run E85 without a check engine light.
I’ve put a few gallons in a couple of times (from empty) but only for some light highway driving and only for about 20 minutes before filling up with regular. I haven’t gotten a Check Engine Light yet(my old GE8 threw one immediately after filling with e85) and am wondering if anyone has run it long term.
I’m not interested in running it all the time, just a tank every once in a while to clean out the fuel system.
Thanks, Jeremiah

 

Why would you do that? Using E85 will get you 20-30% less MPG's. And doesn't improve performance on stock vehicles.

 

Great question; check out my last sentence:
“I’m not interested in running it all the time, just a tank every once in a while to clean out the fuel system.”

 

There is no flex fuel sensor on the Fit. Without it, you'll be putting way less E85 in the mirror than required and running lean. Your motor will die soon. The stock Fit ECU does not have the code to accept or account for the greater volume of E85 required to reach stoichiometric operations.

 

Except Honda makes a specific fuel system cleaners for that. Because even Honda doesn't recommend using E85 in their vehicles.
Straight from Honda's website. I'm pretty sure they know a tad more about how their products work than you do.


"Can I use E85 in my Honda Engine? E85 contains 85% ethanol and must not be used in Honda engines. Using fuels with percentages of ethanol or methanol higher than 10% (E10) will cause starting and/or performance problems."

"E85 is an alternative fuel. It is not gasoline. It is made by combining 85% ethanol with 15% gasoline. Honda engines are not currently certified or designed to run on E85 or any other alternative fuel.

Always refer to your Honda owner’s manual for a list of recommended fuel and the current approved additives."

 

Honestly, with a completely stock non-flex fuel vehicle, I'd be rather hesitant to do anything beyond E10 in the Fit or any other recent Honda without an ethanol sensor to quickly and consistently compensate fuel trim and ignition tables to match the fuel blend.

Like mentioned, you'll be using about 30% more fuel due to E85's stoichiometric AFR being around 9.75 to 1 depending on quality verses E0's 14.7 to 1. Following that with the headache of mixing and calculating the fuels periodically, it would almost be easier to run a top tier fuel cleaner like Berryman's B12 or BG 44k as some examples.

Add to that, potential limitations with fuel injectors and/or the fuel pump depending on the E blend. The factory PCM can only compensate so much (15 to 20% lean or rich short term fuel trim wise IIRC) before you start seeing misfires or lean DTCs that I don't see too much of a benefit.

With that said, if you're wanting to do this then the only plausible thing I've heard of that would make me even consider dabbling with ethanol fuels is produced by eFlexFuel. Its effectively a "piggy back" device featuring an ethanol sensor and its own control unit to sense what the E content is then makes alterations to the base flash on the PCM (be it stock or reflashed via Hondata/KTuner/Honda Tuning Suite). Give it a look at the link attached if you're curious.


I'm tempted to try it out as a means to have more fuel options during road trips but that is a gamble that I'm not quite fully willing to take on just yet. I'd rather try it on my beater Fit before putting it on my good Fit. haha

 

Official Honda licensed engine cleaner. Recommended by Honda for your engine "and fuel system" to do exactly what you are looking for. Without worrying about future engine damage. You can buy it from different places online, or your local Honda dealer will also have other recommended brand options to use as well. Any of those are a much better option than running straight E85.

https://honda-tiongnam.com/product/h...ngine-cleaner/