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I've been itching to do more tinkering on the GLK lately and that has led to me investigating E85.
Mercedes made the 2008 C300 flex fuel capable, and the only difference I've been able to find in the fuel systems from those to my car is the addition of a fuel quality sensor (standard flex fuel sensor). I can't find any wiring diagrams that actually include this sensor though, and I poked around in the variant coding for the fuel pump control module, engine ecu, and front/rear sams and I don't have anything that mentions the fuel quality sensor.
Since I don't think there's an easy way for me to retrofit this fuel quality sensor and I did find a few forum posts indicating that the ME9.7 ECU had flex fuel tables in it from stock I decided to just try draining my tank and adding a couple gallons of E85 to see what would happen. So I did that and while the engine ran great at light throttle or full throttle (butt dyno felt faster) it would cut out and bog at quarter/half throttle.
So since that didn't work I drained the E85 out and went back to 93 and hit up google for E85 tunes or kits for Mercedes and I found this: Auto Products - eFlexFuel Technology
I ordered it on 3/25 and it was at my door from Finland on 3/28. Can't complain about that.
The install was very simple, they include the harness and connectors to make the new fuel line that includes the flex fuel sensor. Just use your multimeter to find positive on your injector connectors and pin the harness properly for that. Plug in the injector harness, make the new fuel line and install the flex fuel sensor, add ground and plug it in.
I was ready to warn the OP about the stinky wrinkles he would run into with an E85 conversion - then I saw who the OP was... ;-)
Very cool. I've wondered about the multiple effects of running E85 in a "regular engine". I have no problem believing that you'll be able to get the right performance out of the E85 fuel. My only question is "what will happen to your mileage"? Alcohol has a lot less "energy" than good old dinosaur gasoline, per gallon, so clearly your MPG should suffer. Most cars will go noticeably further on a gallon of "pure gas" (no alcohol) than they will with the "blended gas" that's available at nearly every pump in the US. Often, with 10% ethanol fuel, your mileage will be about 90% of what it would be with "pure gas" (leading one to ponder the wisdom of mandating 10% ethanol fuel in the first place, but I'm sure the government knows more about automotive technology than the auto makers...) LOL
Anyway, let us know how that works out - it's a interesting and potentially money-saving option that sounds well within reach of us mere mortals.
I was ready to warn the OP about the stinky wrinkles he would run into with an E85 conversion - then I saw who the OP was... ;-)
Very cool. I've wondered about the multiple effects of running E85 in a "regular engine". I have no problem believing that you'll be able to get the right performance out of the E85 fuel. My only question is "what will happen to your mileage"? Alcohol has a lot less "energy" than good old dinosaur gasoline, per gallon, so clearly your MPG should suffer. Most cars will go noticeably further on a gallon of "pure gas" (no alcohol) than they will with the "blended gas" that's available at nearly every pump in the US. Often, with 10% ethanol fuel, your mileage will be about 90% of what it would be with "pure gas" (leading one to ponder the wisdom of mandating 10% ethanol fuel in the first place, but I'm sure the government knows more about automotive technology than the auto makers...) LOL
Anyway, let us know how that works out - it's a interesting and potentially money-saving option that sounds well within reach of us mere mortals.
I average around 18 MPG on 93, on E85 I should expect around 13-14 MPG. The E85 I bought yesterday was $2.74/gallon while 93 octane was $4.05. If the MPG math holds up it'll basically be a wash cost wise, but I drive so little I'm not really concerned about the MPG hit.
E85 burns cleaner and cooler, while being around 100-105 octane. Converting to E85 opens up the door to a low boost non-intercooled (I have 0 room for an intercooler/heat exchanger) supercharger setup in the future.
You're (not surprisingly) already where I was heading ($ per mile). That sounds reasonable, and about right to me (13-14 MPG). Let us know if that's what you get. Of course, your GLK 550 isn't exactly the same platform those of us with a mere GLK 350 have, so the old YMMV warning applies. ;-)
I reset my trip meter after filling up the tank with E85. The app is reporting I'm at 50% ethanol now.
Half tank of E85/half of 93 and these are the results after a short trip in town (lots of idling/stop lights):
I thought I'd remembered that E85 sold for a lot less than "real gas"... maybe I misremembered? According to the link below, E85 costs 20-30 cents more per gallon than regular.
FWIW, I do burn pretty much only regular in my GLK 350, and while I'm no doubt losing some horsepower at WOT, I spend approximately 0.0001% of my time at WOT, so I'm OK with that. ;-)
I looked through the adapter manufacturer's claims - some seem pretty nonsensical but I do suspect that more horsepower is possible due to the higher effective octane rating of the E85 fuel, and that alone could make the whole thing worthwhile for those chasing horsepower. I was hoping for something that might actually save me money on my long (!) road trips... not sure this is going to do it though.
If you're already running 87 then yeah I don't think there would be any point for you. But locally it's around $3.30/gallon for 87, so still $.50 more than E85.
I tried 87 for a tank in mine and it knocked bad. There is a parameter in the variant coding for "low grade fuel" I could probably turn on to fix that, but then it would rob timing and lose power.
Back in the late '00s we had a flex fuel Yukon. New York State was heavily subsidizing E85, but we had to drive 25 miles to get it. Our mileage dropped from about 18 to about 12, so it really wasn't worth it. We would fill up whenever we were in the Albany area, but wouldn't make a special trip to get it.
Cars that were not designed/intended for E85 probably don't have the hardware to deliver enough fuel to match the performance you'll get on dino juice. Add to that, E85 is very corrosive compared to gas, so, unless you happen to have the same materials in your fuel system as a flex-fuel vehicle, you may have problems down the line.
And, who is paying for those subsidies?
(I should be all in; my family has deep roots in Iowa...)
Cars that were not designed/intended for E85 probably don't have the hardware to deliver enough fuel to match the performance you'll get on dino juice. Add to that, E85 is very corrosive compared to gas, so, unless you happen to have the same materials in your fuel system as a flex-fuel vehicle, you may have problems down the line.
This isn't relevant to anything made in the past 30 years.
;-) Bingo - I grew up in Illinois, so we understand the political power behind the humble corncob! ;-)
Anyway, I fully understand that after laboriously transplanting a screaming V8 into a GLK, you do NOT want to compromise horsepower. That would just be WRONG... kind of like putting in a huge picture window facing the ocean and then dark tinting it. ;-)
And I'd forgotten about how nasty ethanol is on seals and O-rings. Back when our glorious leaders took us down the road to ethanol enlightenment, EVERYTHING that burned gas that was built prior to the transition started having problems. I suppose that our GLK fuel systems are designed around having ethanol in the fuel - not sure what increasing the amount 8-fold would do though. I guess we can just wait and ask AA in a few years? ;-)
This isn't relevant to anything made in the past 30 years.
I don't know how you can say that. Regardless, you won't find me using it. I don't drink gasoline and I don't burn ethanol in my cars. I've spent wasted enough time fixing problems due to E10 to know better.
[Edit] Turns out I'd have to drive to Boston to get E85, and I wouldn't do that even if it was free and good for 50 mpg.
Side issue — It’s all but disappeared near where I live. The .gov website shows 6 locations within 10 miles of me. I don’t have a car that can use it anymore but I’ve been to 5 of the 6 and none of them have a pump showing it. Maybe the Kroger listed has it, but their site says only 18 of their 152 locations in Texas have it.
2014 GLK350 base model (active) ; 2001 E320 base (retired); 2001 Wrangler soft-top
Originally Posted by Odd Piggy
Side issue — It’s all but disappeared near where I live. The .gov website shows 6 locations within 10 miles of me. I don’t have a car that can use it anymore but I’ve been to 5 of the 6 and none of them have a pump showing it. Maybe the Kroger listed has it, but their site says only 18 of their 152 locations in Texas have it.
I just checked GasBuddy ... I had to select Houston (and E85) even though we're not near the Houston city limits (our town is not listed on GB and a zip code search results in zero stations). However, I see about four locations I could reach in about 30 minutes time. But we only drive every 4-5 days to go grocery shopping (15 minutes away), and fill-up once a month, so wouldn't be worth it.
https://www.gasbuddy.com/gasprices/texas/
Last edited by calder-cay; Mar 30, 2024 at 03:29 PM.
Yeah it definitely isn't as prevalent as it used to be. One of the reasons I embarked on this journey was because I have E85 available at every Sheetz in my area, and I can always put in 93 like normal as needed. Surprisingly only 1 station is listed as having E85 available on GasBuddy though.
Took a trip to DC for the Defenders game and averaged 14.9 MPG. 162 miles with a lot of stop and go traffic in DC. Before we hit the traffic the car was reporting I was getting 19 MPG.
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