2G E85 black goo, ONLY ON Injector #4... always

[mini zilo]

I am posting this to see if anyone else has this problem. I know that some people get black goo build up, some don't. I usually get a pretty substantial buildup after about 2 months of driving on e85 exclusively.

However, I have noticed that the black goo buildup ONLY occurs on the #4 injectors (closest to the inlet of the fuel rail). On the other 3, there is NO visible buildup whatsoever.

Does anybody have any hypothesis as to why this might be?

To clean the injectors, I soak all 4 injectors in separate baths of 93 octane. The #1, 2, and 3 baths always have clear gasoline in them after soaking, but the #4 bath always has black junk floating in the gas.

Here is a picture of my number 4 injector. As you can see, the buildup is substantial, and it is very strange that the other 3 come out looking squeaky clean...

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[gofer]

All the reading you need on the subject is inside ---> http://www.dsmtuners.com/forums/tuning-engine-management/416147-e85-goo-time-attitude.html?highlight=black+goo

 

[bastarddsm]

I never get the goo on my inectors, but when I had my motor apart last week, all 8 intake valves had about 1/8" layer of the goo built up on them.

 

[gofer]

I never get the goo on my inectors, but when I had my motor apart last week, all 8 intake valves had about 1/8" layer of the goo built up on them.

That's my experience with it too, my injectors clean up by just running 91 through them every few months but my intake valves have black goo on top.

 

[MY1GDSM]

I've Never have had a problem with it EVER in my 1g in the last about 5 years of nearly strait E85 use... .

I still say it something in the Fuel from the source because of that IDK though... Few people have had it tested IIRC

 

[My1GLaser]

Just an idea, but I blend 60% E-85 with 40% 93 octane. After seeing this problem is very common, I will probably always blend the two fuels. I would imagine that 80% is probably where I will end up when I get larger inj. I still get 21-22* timing @ 12:1 AFR flowing 50+ lb/min on my HX-35. I don't have black goo issues after two years of running this mixture.