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50% ethanol mix?

Z

ZippyDan

Platinum Member
my mom just told me she accidentally put 50% ethanol in her tank before she realised her mistake. she filled the rest of the tank with regular unleaded (which i think has 10% ethanol anyway). this is in a 4cyl hyundai. i figure it will probably fine, but im always curious for details. anyone?
 
where the heck did she find E50? i have never seen it before, sure it was not something else? i have seen E10 E85 and E100 before.
 
I'm not sure, but I think the E85 cert'd vehicles may have different materials used for their gaskets and such.

It's painful, but you might want to take that thing on a highway trip and run it out of gas a much as possible, then fill up with regular gas. I'd rather blow one tank of gas than eat the fuel system up.

Who knows though...probably it'll be fine... 😕

Chuck
 
Its not the gaskets and lines you are going to have to worry about unless you run ethanol all the time. Its running lean but at 50% e85 its still probably not a big deal. Just don't beat on it until you run this tank out.
 
The big question is how much did she put in? If it was just a gallon or two she'll be fine. If she filled up with it and then topped off with the regular unleaded she may have an issue.

Personally, I think she'll be ok. I would keep on diluting it by topping off with normal gas every time she burns through a gallon or two.
 
The biggest changes made to "Flex-Fuel" vehicles are changes to their fuel delivery system to materials that are less susceptible to the corrosiveness of E85. One tank should not do that much harm.
 
It sounds like she pumped half a tank of E85 and then filled up with gasoline.

I'd just burn it down to half a tank and then fill up with gasoline again.
 
The car should run noticeably poorly if it's too lean a fuel mixture. You'll also get a check engine light more than likely with a code relating to an O2 sensor or MAF sensor or just fuel mixture lean on bank X. If that starts happening I'd siphon out about half the tanks worth of gas and then fill it up with straight unleaded. Shouldn't run it lean for too long or you could damage the engine.
 
Originally posted by: desy
OMG Nothing will happen to that car
just run out the tank and put regular back in next time
Click to expand...

This.

Sheesh people, ethanol will do nothing to to the engine at all as there is no difference between a flex fuel engine and a "regular gas" engine. The differences are in some seals, lines, and usually the gas tank. I love how people have bought into so much misinformation about ethanol. Should you run it all the time at high concentrations? Probably not, especially when under warranty but you could run a blend higher than 10% all the time without adverse effects in "normal" cars. Performance cars may be a bit different but I can't attest to that.

I found that running about a 40-60% E blend gets the best cost per mile in my FFV Town and Country.
My '06 Sebring also runs the best cost per mile on about a 25% blend.
 
Not exactly. The computer needs to be able to tell how much ethanol its using so it knows the proper air fuel ratio to run at. A standard computer can't. Gas runs at 14.7:1 while e-85 likes 9.8:1.
 
Originally posted by: thedarkwolf
Not exactly. The computer needs to be able to tell how much ethanol its using so it knows the proper air fuel ratio to run at. A standard computer can't. Gas runs at 14.7:1 while e-85 likes 9.8:1.
Click to expand...

Yeah it's like running lean, which is bad for an engine
 
Originally posted by: Throckmorton
Originally posted by: thedarkwolf
Not exactly. The computer needs to be able to tell how much ethanol its using so it knows the proper air fuel ratio to run at. A standard computer can't. Gas runs at 14.7:1 while e-85 likes 9.8:1.
Click to expand...

Yeah it's like running lean, which is bad for an engine
Click to expand...

That may be true for performance engines but isn't shown to be the case on normal engines from what I've read. Also, I do not(and did not) advocate running E85 in "normal" cars anyway, as they will run a bit leaner. What I did say is that you could easily run a percentage higher than 10% without causing adverse effects. Again, if you have a performance vehicle - stick with what is recommended, but as to the OP - there should be ZERO issues with running a 50% blend especially if it's only 1 tank.

Also as to the "computer" issue - it really depends on the range it's programmed for. Most will be able to handle the changes in A/F ratio of a 50% blend but beyond that it really depends on where the limits are set(which could cause your idiot light to come on).
 
I'm talking out my ass here but...

Don't they put like 10% in the winter blend every year? If that is the case, I have a hard time believing that one tank of 50% ethanol is going to amount of a hill of beans one way or the other.
 
From Wikipedia:

There are a few major differences between FFVs and non-FFVs. One is the elimination of bare magnesium, aluminum, and rubber parts in the fuel system. Another is that fuel pumps must be capable of operating with electrically conductive ethanol instead of non-conducting dielectric gasoline fuel. Fuel injection control systems have a wider range of pulse widths to inject approximately 40% more fuel. Stainless steel fuel lines, sometimes lined with plastic, and stainless steel fuel tanks in place of terne fuel tanks are used. In some cases, FFVs use acid-neutralizing motor oil. For vehicles with fuel-tank mounted fuel pumps, additional differences to prevent arcing, as well as flame arrestors positioned in the tank's fill pipe, are also sometimes used.
Click to expand...

In other words... long term use will result in magnesium, aluminum and rubber parts breaking down, a lean running engine and greater chance for fuel pump related problems.

My advice would be not to let it get below 3/4 of a tank for 500-1000 miles... you want the pump to stay fully submerged in fuel to prevent arcing. Also, you may want to change the oil sooner than normal, especially if you get the quickie $20 instant oil changes that put the cheapest oil on the market in. Blow-by from E85 will shorten the life of cheap natural oil.
 
Originally posted by: CADsortaGUY
Originally posted by: Throckmorton
Originally posted by: thedarkwolf
Not exactly. The computer needs to be able to tell how much ethanol its using so it knows the proper air fuel ratio to run at. A standard computer can't. Gas runs at 14.7:1 while e-85 likes 9.8:1.
Click to expand...

Yeah it's like running lean, which is bad for an engine
Click to expand...

That may be true for performance engines but isn't shown to be the case on normal engines from what I've read. Also, I do not(and did not) advocate running E85 in "normal" cars anyway, as they will run a bit leaner. What I did say is that you could easily run a percentage higher than 10% without causing adverse effects. Again, if you have a performance vehicle - stick with what is recommended, but as to the OP - there should be ZERO issues with running a 50% blend especially if it's only 1 tank.

Also as to the "computer" issue - it really depends on the range it's programmed for. Most will be able to handle the changes in A/F ratio of a 50% blend but beyond that it really depends on where the limits are set(which could cause your idiot light to come on).
Click to expand...

The computer won't change the a/f ratio for ethanol thats the problem. It just keeps running ethanol at the same a/f ratio as regular gas because it has no idea it isn't regular gas. Again 50% of e-85 isn't a huge deal since the a/f ratio wouldn't need to be that much different but it still isn't good.
 
Originally posted by: PingSpike
I'm talking out my ass here but...

Don't they put like 10% in the winter blend every year? If that is the case, I have a hard time believing that one tank of 50% ethanol is going to amount of a hill of beans one way or the other.
Click to expand...

but but but.... 😉

Hell, "regular" is E10 here.
 
ok i guess it was confusing. she put in half a tank of E100. then filled the rest with normal gas. thats how i got to 50% mix. although since normal gas is already E10 i guess its more like a 55% mixture. no problems so far...
 
I probably would have had the tank drained... if for nothing else than to put her mind at ease. I don't think it'll do any permanent damage though... just be sure not to let it go too far before changing the oil... alcohol tends to "wash" the oil off cylinder walls if the oil isn't designed to be used with fuels with high alcohol content.
 
Originally posted by: ZippyDan
ok i guess it was confusing. she put in half a tank of E100. then filled the rest with normal gas. thats how i got to 50% mix. although since normal gas is already E10 i guess its more like a 55% mixture. no problems so far...
Click to expand...

E100? Can't get that in very many places as far as I know. E85 is what FFVs are "rated" for.
 
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