losing faith in fuel adds -- piston photos....

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before pic....
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after 3 techron treatments, and about 5k miles of FP60...
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I think it looks even worse now!!
 
same problem as me, though mine runs rich and setting it any different puts it out of time spec... maybe yours is running rich? engine, miles? one of my pistons looks like that top photo, like a wet carbon...most likely oil, the others are dry carbon...
 
I can't see jack in those photos....
but if they look like I think they look like, I'm not sure what will get piston tops clean short of water in a vaccum line in a gasser.
 
For combustion chamber cleaning probaby best to do Italian Tuneups and/or water decarbonization.

For injectors, fuel pump, and lines in general, I would suspect some of the cleaners would work.
 
any of the more experienced experimenters can chime in anytime during my post....

could you not drop half an ounce of lc-20 in the cylinders to soften the carbon deposits up? turning the engine over by hand a few times to get some added scraping in there.
 
quote:

Originally posted by Pontius Pilate:
maybe yours is running rich? engine, miles? one of my pistons looks like that top photo, like a wet carbon...most likely oil, the others are dry carbon...

enigne is nissan VQ30 in a '99 maxima w/80k. A/F ratio is completly computer controlled and I have no trouble codes, so I don't think there's anything I can do about that.

quote:

try autRxing to get the ring packs clean so you don't get blow by

did ARX 6k miles ago. compression was >200psi even before ARX. spec is 185. so no blow by. and it doesn't burn so much as a drop of oil either.

I'll take a look at the EGR and PCV stuff.

I've considered water, or the LC20 Molasoak, but these just seem a bit extreme to me. I concerned about screwing something up.
 
I can't see much either.

When you shine a light to the top of the piston, is it a thick coating or a thin, surficial coating?


A thin, surficial coating will always be present unless this engine is really running very lean and very hot.

Also consider this, fuel companies change formulas all the time as well.

Be glad you had an additive that prevent gum and varnish buildup in the system or there wouldn't have been any fuel to burn and to coat the top of the piston.
 
I see what you mean about the sandpaper appearance. See if you can insert something non-damaging that allows you to scrape the surface to see "what's up" (is it a layer or is it from a rough piston surface?). My VW 1.8T engine piston tops show the piston machining marks (swirls) with a thin layer of dry carbon.

dailydriver, to avoid hydrolock the amount of water ingested per time must be low enough. Figuring out how to achieve that is the hard, guessing part.
 
What are we looking at?? All piston tops are black no matter what you put in there its the by product of fuel (carbon) all you can do it put good gas in there with fuel treatmets in between is all you need. I would be more woried about keeping the rings clean and thats the oils job.
 
For water cleaning Go to a feed store and get a 2 Oz syringe. Fill with water and slowel inject into the pcv hose of a hot operating engine. Never caused any harm in my applications. In lawn mowers I just remove the air filter and spray a "MISt" into (Not a stream) the barrel.
 
I can see what you mean by deposits.

I have seen this on every engine ive peered into.

IMO, piston top deposits arent a big deal... large buildup that reduces CC volume are the issue. These arent causing them.

are there real sizable buildups around the spark plug holes or injectors? If not ,no issue.

JMH
 
Regane is FAR at AAP (limit 2) until 4/29 so if you wanted to give that a try before delving into anything else, or giving up on additives altogether, now's the time to buy it.

I certainly haven't read everything on this forum, but my impression is that Regane has a decent reputation around here.
 
hmm. maybe these photos don't show up very well on some people's computer screens. on mine it's quite clear - looks like a layer of black sandpaper on top of the piston.

it's hard to tell how thick the layer is. compression is >200psi, which is 15psi too high. I attribute this to carbon in the combustion chamber.

looked at a friend's 2k V6 camry pistons and they are bare metal. he runs regular. I run premium shell Vpower.
 
in my opinion, 2oz of water is not enough to do much of anything. the last time i did a car (92 vw golf) we went through 3 quarts over the course of about an hour. dribbled it slowly through a hose hooked up to the intake hose right in front of the throttle body. ran it down the highway on a warmish day and put it through a basketball air needle. we tried using about 25% rubbing alcohol on the first quart, did not seem to make a difference. when we got done, it ran alot smoother than it did when we started. power seemed decent to me for a car with 170k miles on it but i do not drive the car every day to really tell. the lady who owns the car raved about how well it pulled on hills after we tuned it up and cleaned it out.
 
2 oz is a complete joke when it come to carbon removal with water.

You need close to 1/2 to 1 gallon when I did it to do anything.

Here is where I did it, took almost 1/2 a gallon.
 
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