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In older cars sure, but fuel systems have been designed to be chemically tolerant of Ethanol since the banning of MTBE as a gasoline oxygenate. My take from the various literature is that Ethanol being a really good solvent, any contamination along the entire supply chain up to and including the junk in your cars fuel system will be dissolved and accumulate in the injectors. I have also read that the recirculated gasses from PCV etc when coming into contact with the injectors cause an accumulation of junk. Its probably a combination of all the above and some other misc factors. Injectors get clogged all the time just running straight gasoline too so its not like its a unique problem to E85 either. Plus the stuff MinusPrevious just posted.
MinusPrevious is correct on the primary source of the black gunk. There is evidence that PCV or EGR can contribution. Old non-ethanol compatible hose argument may have some truth, but it doesn't apply to the Evo fuel system. Its totally up to the job.
MinusPrevious is correct on the primary source of the black gunk. There is evidence that PCV or EGR can contribution. Old non-ethanol compatible hose argument may have some truth, but it doesn't apply to the Evo fuel system. Its totally up to the job.
Im certainly not the one credited w/that analysis. The poster was a petroleum engineer type.
I did some internet searches & the PIB casual factor has been reported by more than a few experts in the field
I've had a set of injectors lying around for years.
They've only been used with petrol and when it came to flow test time they were all severely blocked. 25% or so of the original flow.
After soaking in ethanol for a while (flow testing also with ethanol), most of them recovered their original flow values.
That's because petrol, even though it's a really good solvent, there's insoluble impurities in the fuel which cause blockage.
What isn't soluble in petrol IS usually soluble in alcohol.
Well after several years of trying different things and almost destroying my motor, I think I have the gunk issue resolved on my Evo. I've had an ongoing issue ever since moving to Portland about 10 years ago. I used to be reasonably certain that the only possible source of gunk for an Evo was via gums left over in lower quality gasoline that is usually mixed with ethanol to make E85. There are several studies indicating this as one possible source, and this idea correlated well with the move to Portland and the switch to a different source of E85. More recently (in the past five years) there was some evidence on EvoM that oil from PCV could cause an issue. The notion here is that not all of the constituents in the oil are soluble in ethanol/gasoline combo, and as the e85 carries away the soluble part, it leaves the insoluble portion behind near the tips. However, I have a hard time understanding how gunk could settle out on the injector tips when the fuel is being sprayed out a high pressure. Perhaps the pocket were the injector sits causes a local low pressure spot that draws in the some of the insoluble leftovers after the injector stops spraying? Anyhow, since I haven't been using PCV to ventilate my crankcase for the last 3-4 years, that wasn't a possible source of gunk for my Evo, and I didn't really give it any serious thought.
Since I was convinced the gunk was coming from the fuel, I decided to try some fuel additives, but none worked. I unfortunately put a little more faith in the additives than I should have, and I very nearly killed my engine due to running lean from gunk build up. The engine had to be partially tore down, but it was found that pretty much everything was salvageable. One thing that was found during the teardown was that the intake valve guide seals were toast, I think pretty badly so. Besides the injectors being gunked up, there was a thick trail of gunk on the intake ports below the injectors.
After 2000 miles of post-rebuild driving in warm weather where the gunk tends to be the worst, my injectors are 100% perfect. Not a single indication of gunk buildup. Before the rebuild, the injectors would be a huge mess by 2000 miles.
Since oil fumes from PCV have been blamed by others, it seemed reasonable to guess that the blown intake valve guide seals were allowing oil into the intake. The challenge with this being a realistic possibility is that valve stems protrude into the intake path further down than the injectors do. So how can oil leaking down the guides get to the injectors? Here's my explanation: During off-boost driving, the vacuum suction will pull fumes through all the eight intake guide seals at all times, regardless of which cylinder is pulling in air. That allows oil fumes to travel up the runners of the cylinders with closed intake valves (oil fumes passing the injector for that cylinder) and then back down the runner with the open intake valves (oil fumes passing that injector as well).
There may also be another possible means for oil fumes to reach the injectors. In high intake/exhaust timing overlap scenarios where the intake valves open while the combustion chamber still has combustion products, some flow up the intake runners can happen. If the motor has serious oil consumption issues, it's possible that this could allow some oil fumes to reach the injectors. I think this is a pretty low probability though because the combustion event should burn up most of the oil leaving little, if any, oil to reach the injectors.
So my recommendation to anyone with E85 injector gunk issues would be to have a look at your intake valve guide seals as part of the investigation of the cause.
Wasn't it decided the gunk was from left-over fuel, in fuel station storage tanks, that were now being filled with e-85? It's been a few years, but I thought that's what some official report or somethin' or other stated.
Since e-85 has been in those tanks all this time, there doesn't seem to be an issue with gunking any more. Not that I've seen since 2017, anyway. Is it still going on?
I always buy extra fuel when I go to the station. The places I go are not dodgy or low traffic. I've been using the same containers for probably ~5-6 years now. This is what they look like on the inside.
That gunk is all pretty caked on, its not going anywhere.
Wasn't it decided the gunk was from left-over fuel, in fuel station storage tanks, that were now being filled with e-85? It's been a few years, but I thought that's what some official report or somethin' or other stated.
Since e-85 has been in those tanks all this time, there doesn't seem to be an issue with gunking any more. Not that I've seen since 2017, anyway. Is it still going on?
Garbage in the storage tanks is definitely a possibility. I don't think that's the issue with my Evo though. Abacus who is located on the East Coast has told me that he thinks that high humidity can also contribute to gunk formation.
No I think it was just in the fuel and got stuck to the inside of the cans. The cans themselves don't seem to be degrading at all.
Oh, I see what you are saying. Hm.. I suppose that could be a possibility, especially if they sat with a mixture. Interesting.
Originally Posted by mrfred
Garbage in the storage tanks is definitely a possibility. I don't think that's the issue with my Evo though. Abacus who is located on the East Coast has told me that he thinks that high humidity can also contribute to gunk formation.
Moisture from the humidity? That would suck. No way to avoid that for some.
but when i buy e85... when i look in my fuel cans it looks like water.... just as clear as can be...
during the summer it always test around the 90% mark... ive seen as high as 93%.
Also... i always use lucas ethanol fuel treatment because the car sets alot.
couple interesting things.
if i test the fuel before i put in the fuel treatment... it test like it should. when i test it after the fuel treatment... the test does not work. it looks as if the fuel treatment prevents the water from separating in the fuel... therefore, always burning the moisture... out. which is what you want.
Also, when pulling injectors, intake... the injectors always look new. the intake looks like it just came out of the machine shop and the valves are look squeaky clean.
AMS intake so no EGR.
My components are also always clean. My only complaint is the corrosion on the fuel pump and hangar. It's not horrible, but I still don't like it.
I've not seen any corrosion on my fuel pump body. Are you by-chance using a custom metal hangar that is making metal-to-metal contact with the fuel pump?
Sep 12, 2017, 02:31 PM
