E85 + Black Gunk/goo

[blah_blah]

I've done a search on SAU on this topic but there seems to be no conclusive answer on what causes the 'black gunk/goo' that some people have with running e85.

This is what has happened to my car:

Blocked injector with black gunk, and all inside the head of my engine.

This caused me to loose compression in that one cylinder

Flow tested the injector and it was less than the others. It was noticed that in the flow test on start up that there was no fuel coming on within the the first second or so

Scrapping some of the stuff out of the head:

It has a rubbery feel to it. Put it with Unleaded 98 and it verly slowly disolves when you rub it on your fingers. Dissolves even faster with brake cleaner.

No signs of the stuff in my fuel filter.

Now a search on the internet many people have this issue:

http://codsm.org/forums/showthread.php?t=3965

Explanation by a chemist who analysed the stuff:

uote:

Alright, I finished my analysis of this stuff, and my finding is very unexpected. I think it will
probably surprise everyone else as well. This doesn't appear to be forming because ethanol
is "such a good solvent" but because ethanol is a poor solvent. I suppose it should have
been obvious when others said that it "washes right off with gasoline". Why would
something that ethanol is selectively dissolving wash off with gasoline? If this were
something in rubber or from our fuel tanks, wouldn't that imply that gasoline would dissolve it even more readily than E85? Alright, so what is this stuff? It is a appears to be a very large petroleum based
hydrocarbon, similar to Vaseline. There isn't a single hetero-atom in the molecule (ie, the
entire molecule is comprised of hydrogens and carbons), but the molecule is very large. It is
also completely aliphatic (ie, only single bonds in the structure - no double or triple bonds).
Where did it come from? I can only think of two different sources it could be coming from.
It is either something that is mixed in with the rubber hoses that is meant to dissolve away in the gasoline, or it is a trace impurity in the 15% gasoline that is in E85 that wasn't
separated during the fractional distillation process. Because it is such a large molecule, it
wouldn't be very soluble in ethanol and could easily crash out of solution at the injector.

Quote:

So, let me see if I can wrap my decidedly non-chemist brain around this: This "very large petroleum based hydrocarbon", or vlpbh , is able to be completely dissolved into gasoline, essentially becomes part of that fuel, and is burned up in
combustion, never to be seen again except broken down as part of the exhaust gasses out
the tailpipe. However, with ethanol, the vlpbh is more or less "dislodged" from the rubber or
distilled petroleum, and is carried by the ethanol as a separate particulate of sorts, perhaps
partially burning during combustion (that which makes

Scotty's 2 cents:

I think they are looking at it from the wrong end, I believe it is carbon coming back from the combustion chamber, as the intake valve opens. Similar thing happens in direct injection motors as the petrol isn't cleaning the runners.

It is not in the flow path as the ethanol pushes that out the way. The modified 1000's are actually good for this, as the tip isn't large enough to gunk up too much. I doubt there will be a flow difference unless the filter inside the injector is blocked.

Those 1000's I mentioned above had a little filter added in the top, which was the likely cause of the flow issue he had. I never run those little secondary filters anymore, they are too fine and block up easily.

Another explanation:

http://www.gtrlife.com/forums/topic/86794-extra-maintenance-required-for-flex-fuel-or-e85-gt-rs/

E85 fuel is a strange beast, it is 85% ethanol and 15% gasoline. This creates two unique problems; (if you don't want the read all the science, the bottom line is add Valvoline Water Remover and Gumout for flex fuel several times a year and your good to go)

Ethanol is hygroscopic (loves to absorb water) but when combined with 15% gasoline, the water will drop out of the ethanol at only 0.5% concentration. What that means is, in the morning when it's cool with high humidity the E85 is sucking water out of the air, then letting it drop out of solution and settle in the bottom of your tank. Fortunately there is a very easy solution; once or twice a year add a water remover that has isopropyl alcohol base like Valvoline Water Remover. The brand isn't important, what you need is isopropyl alcohol based additive. Rubbing alcohol will work, but you will need to add a lot of it, because it contains 30% water to keep it from evaporating too fast when your Honey rubs it on your back .

The second unique problem is, the 15% gas in E85 has detergent added to it, one of which is Poly Iso-Butylene. It is a excellent detergent in gasoline, but it SUCKS when it is in a 50% or greater solution of ethanol. For some complex reasons, it actually becomes insoluble and plates out on injectors and valves. The EPA has know this since 2007, but has not changed the rules that force gas companies to add it to ALL gasoline (except racing fuel). GM and Ford have both tested E85 engines and found that in normal in-town driving the fouling can become significant in as little as 5,000 miles. At highway speeds the fouling slows significantly, to the point that it is a non-issue. Again, there is an easy solution; use an injector cleaner that is formulated for flex fuel and contains methylal. I only know of one, Gumout for flex fuel. There may be others, I just don't know of them.

So a few people flush it out with fuel cleaners or running a tank of 98 once in a while.

Im curious if anyone on SAU has looking into this issue, and what they found what causes it?

Why do some cars have it and some cars don't? There are lots of guys running e85 who they believe dont have any issues?

[blah_blah]

Well i think i found me answer

http://www.evolutionm.net/forums/evo-engine-turbo-drivetrain/486458-3-tanks-e85-look-my-id2000-s-unreal-7.html

Hi,

I don't post often on this particular forum but I just came across this thread and the other one in the alternative fuel section. I am an engineer, and I have been following industry developments in alternative fuels.

I doubt many of you are aware of this, but GM had a production port injected turbo flex fuel engine all the way back in 2007. It was a Saab variant of the Ecotec engine family. Saab did extensive testing on a lot of boosted E85/Flex fuel issues and published some work on it. See Bergstrom, "The New ECOTEC Turbo BioPower Engine from GM Powertrain," 2007 and Bergstrom, "Alcohol Based Combustion Engines - Challenges and Opportunities," 2007. Deposit formation is one of the dirty little secrets of E85; another is pre-ignition.

GM found the exact deposit problems many of you are experiencing. I have read a lot of different ideas on here about the nature of the problem and I have read a lot of speculation about solutions for it. Here is what we know for sure about the deposit issue, based on GM's internal research.

Chemical Origins of the Deposits

The deposits primarily consist of "Poly Iso Butylene," or PIB, a cleaning additive in the gasoline portion of commercial E85 blends. As far as we know, the ethanol itself doesn't directly cause this type of problem with injector and valve deposits. This PIB additive was never designed for use in high ethanol concentrations.

PIB is designed to soften engine deposits, but below a certain concentration (by total fuel volume) it is actually counter-productive. What happens is that with insufficient PIB by volume, the normal valve deposits don't soften. The PIB actually combines with these normally occurring deposits and makes build up worse.

Running PIB-free E85 is basically impossible in a practical sense. GM engineers ordered special batches of PIB-free E85, but in the real world the E85 still becomes contaminated with PIB because the entire fuel refining and transport infrastructure has traces of it. Still, with this very low PIB concentration E85 deposits can still occur at similar rates.

A lot of people on here have speculated something along these lines.

Effect of Drive Cycle

Deposit formation is highly dependent on vehicle use and overall drive cycle. This whole issues is complicated, but aside from the makeup of the actual E85 blend, drive cycle is the #1 factor in these deposits.


Bergstrom, "The New ECOTEC Turbo BioPower Engine from GM Powertrain," 2007, Internationales Wiener Motorensymposium 2007, p. 29

On the left is a multi-hole type (not pintle type) fuel injector after 15,000 km running a GM in-house designed drive cycle to simulate major stop-and-go city driving. On the right is the same type of injector after 60,000km in a high-speed (mostly highway) drive cycle. Both engines were running the same commercial E85 blend in Sweden, consisting of 95 RON fuel and denatured ethanol.

Drive cycle variations may not explain absolutely everything but it is a reasonable hypothesis for why two vehicles running the same E85 blend can have such variability. This can also partly explain why somebody doing a lot of highway driving (rural driver or suburban commuter) who always runs E85 may never experience noticeable deposits.

Using Fuel additives and Normal Gasoline blends

There are a lot of fuel additive blends out there and they change all the time so I can't speak for all of the various formulations. What we do know based on GM's research is that PolyEther Amine or "PEA" , which can/used to be found in Techron products, cleans valve deposits but does not clean injectors with this problem. In fact, too much of fuel system cleaner could make the problem worse.



So how do we clean up the deposits if an engine is prone to them for whatever reason? Put "normal" gasoline blends in the tank and it will go away within 1 tank. You don't even need to pull the injectors.



Most of you already knew that. It's not really news; it just confirms with reliable sources what has been widely understood.

Conclusion

So yes, I didn't have any earth-shattering solutions to present, but I did clear up some of the mechanisms for this deposit formation. The deposits are caused by the gasoline portion of E85. The two biggest factors in deposit formation are the additive mix in the fuel and the way you drive the vehicle. Fuel system cleaner products are innocuous at best, counter-productive at worst. The type of injector or fuel system you run might matter some but they are not part of the mechanism of deposit formation.

So if you figure out that your engine is prone to these deposits, be mindful of stop-and-go traffic and put gasoline in your engine sometimes to clean it out.

Hope that helps.

[GTSBoy]

The lack of consistency between reported users will be because;

A) there is more than one source of E85, with different origin of ethanol and hydrocarbon parts,

B) it is being used in many different cars from different manufacturers with different remnants of stock and modified fuel systems.

Add those 30 variables together and try to get everyone to have the same result.

[Leroy Peterson]

hmmmm

what strikes me as strange is how these chunks are getting passed the fuel filter. the only thing i could think of is to install one as close to the injectors as possible and after a while open it up and see whats in there.

Unless its forming when stationary?

Any idea how this goo has an affect on a compression test?

[GTSBoy]

That stuff would cook in the injector after shutdown. Nice and hot, no flow.

[XGTRX]

Sugar cane product + water + heat = toffee.

[Serpandrew]

Interesting, i've been running United e85 for close to a year and a half now and my injectors look like new

[Blackkers]

I had this gunk on my side feeds after running e85 straight for 9 months

Back on 98 no issues they're clean again

[Leroy Peterson]

Sugar cane product + water + heat = toffee.

All info above points to the unleaded additives to e85 as the culprit, not the ethanol.

[scotty nm35]

As I have posted before, I suspect it is deposited on the injector from blow back of exhaust gasses as the intake valve starts opening. That's the only place I see black carbon coming from. It's very common in direct injection motors, worse so with overlapped cams I suspect.

The other suspect is molasses from the heat in the plenum and hot rail.

What worries me more is that only a couple were gunky. Could those valves have been not seating correctly?

I hear the flow test came up with sticky pintles, what micron filter were you using again?