Reminder if this is old news, heads up if it isn't.
I've run E85 in many of my own cars and cars that I've worked on or tuned for years without issues. The biggest reason for that is because in most of those cars I wasn't running or recommending full E85, usually a 50/50 mix of premium gas and E85, which gives you E47. In my LSA powered Sky I've been running full E85. I try to run a tank of gas through it once in awhile, but usually I don't because the power of E85 is so addicting!
So awhile back I started getting fueling issues at WOT, the logs were showing it was starting to run lean but the fuel pressure looked fine. Looking at the narrowband O2 sensor readings actually showed me what was happening, the injectors were plugging up! You could see the difference in the individual cylinders that the injectors were plugging up in by looking at the narrowband O2 sensor traces in the Chart Display. Anyway, I ran some injector cleaner and straight gas through it and they cleaned up fine. The fact that they came clean so easily told me that it was from the ethanol, so I pulled off some of the lines and regulator and sure enough, the tell-tale black gunk was there. So I decided to go drastic and switched out the entire fuel system including the fuel tank to E85 friendly components. I'm now running an entirely new fuel system with a new fuel cell, pump, filter, regulator and lines. Everything was awesome until a few weeks ago when I noticed that the logs were again showing it going lean at WOT, but this time the fuel pressure was also dropping off.
I pulled the fuel filter element out, the one that was brand new 6 months ago, and this is what it looked like....
That was a container of clean, straight gas that I dropped the filter element in. As you can see, it turned the gas black. REALLY black! The inside of the filter element looked perfectly clean and like new, so the filter did it's job, that's for sure. The injectors didn't plug this time, the filter stopped the gunk from getting to them. That's why the pressure was dropping off, the filter was starting to plug up. Again, this is a brand new tank and components, and I have gotten E85 from the same couple stations for years. Did I run a tank or two of straight gas through it in the last 6 months since I put the new tank in? Ummmm, well no. Guess what? YOU NEED TO! lol. That's the reminder or heads up part, if you run full E85 you should really run some straight gas through it once in awhile.
That's also why I REALLY like running E47. It gives 90% of the power of full E85 and doesn't kill your mileage nearly as bad. The other plus is that you'll most likely never have fuel gunk or plugging issues with E47. I'm not a chemist so I don't know exactly what the black gunk consists of, but I do know that straight gasoline dissolves it with no problem at all. And it thins it out enough that I'm sure it has no problem going through injectors or filters once it's mixed with gas. This is also a testament for the Aeromotive 10 micron fuel filters, it did it's job. I'm thinking about trying the stainless mesh filter element because it would be cleanable in this situation, but I'm not sure this black stuff wouldn't go through a 100 micron stainless mesh filter. (???) The 10 micron filters are fabric and it doesn't look like soaking it in gas is going to get all the black out of the filter. (I left it soak in a bucket of gas overnight so I'll see in the morning. If it looks like new again I'll reuse it. If not, I'll buy a new element.)
Sorry if this is old news for some. Others might not know this is an issue with full E85 and that they should run straight gas through their cars every once in awhile. The only problem with that is once you and your car get a taste of corn, it's REALLY hard to go back to dinosaur fuel! Even for a single tank's worth of driving! I think I might work on dropping back down from full E85 towards E47 to see where the power starts dropping off in this LSA. It's kind of a pain to go to two different pumps when filling up your tank but running a constant mix of ~E60 or so would probably be better than running a full tank of crappy Cali pump gas through it.
edit- Just answered one of my questions above... The Aeromotive filter that's on the bottom of my fuel pump/pickup is a 100 micron filter. It was spotless clean. That means that the 100 micron filters will NOT stop this black gunk, it will go right through it. (I have a 100 micron filter before the pump, then the 10 micron filter after the pump.) The paper 10 micron filters are obviously a must for E85 systems, you just have to make sure they're not getting plugged with the black stuff.
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Originally Posted by Area47
