RI A6

I had a good talk with my Audi RS4 technician today about FSI engines. It seems that they are beginning to see a large number of cars with FSI coming in with multiple cylinder misfires. (sound familiar) Pulling the heads they find deposits on the cylinder heads and valves. Their (Audi's) diagnosis is poor fuel quality. (This is exactly what happened about 3 months ago to an RS4 owner on Cape Cod.) The official Audi solution is to switch to Shell V-Power for it's cleaning capabilities. (I guess those of you who don't have Shell stations in your neighborhood will have to move.)

This was a large enough problem that it has become a point of training in their weekly service staff meetings.

Keep your ears open and ask questions when you go in for 5K or 15K service. My service tech says it is an issue across the entire FSI engine line.

I have some thoughts about whether this is actually a fuel related problem, or not. The question is, why are the deposits there in the first place.

RSfizzy

Would a fuel octane booster or fuel system cleaner clear the deposits?

daveak05

Which is causing which? The deposits I would think are a direct result of the misfiring, if left unchecked.

Blaming it on the fuel, how nice. Now, across the entire country, FSI owners need to worry about the fuel going into their tank??? That is as bogus as a 3 dollar bill, and solutionless.

RI A6

It's the same group that are also analyzing our oil and changing it regularly under Terry's recommendations. It's not a big group, maybe 8 of us now, but so far none of us has had misfire issues that I am aware of. He suggests FP60 or (recently) Bio Plus, for their injector, upper cylinder, and valve cleaning ability.

Is it making a difference ... maybe. As Doug Feith says: "absence of evidence is not evidence of absence"

http://www.lubecontrol.com/fuel.htm<ul><li><a href="http://www.renewablelube.com/products/pdf/Bio-Plus%20Injector%20Cleaner%20Gas%20Conditioner.pdf" >Bio Plus</a></li></ul>

daveak05

Yes, at the injectors, valves, and valve ports...but, if it's inherent to these engines, you're fighting a losing battle. Hook it up to a full fuel system cleaner, IV type, to get the best results.

PGM

I have two 4.2Ls in a Q7 and RS4. Is this an Achilles Heel in the making? My engines are getting a dose of 10% ethanol whether we like it or not. Perhaps, this may have some scavenging properties. Very disturbing report on FSI! What are your additional thoughts on this developing anamoly? TIA.

RI A6

<center><img src="http://www.fourtitude.com/news/uploads/Motorsport_News/084__scaled_600.jpg"></center><p>Deposits are either caused by:

a) overly rich mixture

b) unburnt hydrocarbons (due to misfires?)

c) oil deposits

Seems to me "bad" fuel is one which does not have enough detergent additives to clean the gunk that the engine produces.

Hey, and guess what the latest Shell V-Power ads are about?

daveak05

See, I don't know which major gas brands would be even slightly inefficient in cleaning properties. I mean, they would have problems immedately.

You can always get bad fuel in isolated cases, but the detergent properties of the fuel need to be at a very high(standardized) level to prevent this very thing, not to mention emissions systems.

From Shell to Chevron to Mobil to Exxon, et...no one has detergent advances on the other. When you also take into consideration that a single refinery may be blending for several brands, it becomes even more unclear.

I've always viewed the occasional gas commercial touting a new clean running gas as simple marketng. It's like Bud saying they use only the finest malted barley...when they use rice as a substitute in large quantities.

Rapture

I have always used Shell V-Power. (actually I have come to think of it)

McQueen993

I agree. Ethanol is crap. I mistakenly filled my 993 with fuel with additional ethanol mixed in and presto...check engine light due to misfires.

I'll gladly pay more for real gas. Someone please tell me where I can find it though.