I had been reading some old threads about possible carbon build up on the valves of the new DFI engines. It seems some convincing evidence was presented to support this, yet I don't think I read of anyone who has actually removed a valve cover from a 997.2 and taken a look for themselves to see what the valves look like. Does anyone have any new information about this issue.. if it is even an issue

 

I would like to know if this is an issue as well, especially since it's been noted serveral times on here that the new DFI engines burn more oil. Burning more oil to me means more potential build-up on the valves. Would be great if a 997.2 owner could shed some light on the subject.

 

IMHO no one will know anything until those new engines will start hitting at least 50K miles age in average, in 3-4 years to come. then we will probably have some statistics for observation...

 

I do hope you are correct or that Porsche has engineered around the issue. Unfortunately, from web info it seems the problem creeps up sooner than 50k

 

The only suspicious info I`ve seen to the date were multiple complaints (but not from every new 997.2 owner) of high oil burn rate on new engines - like somebody posted having oil below minimum from max mark in 1600 miles or so? It does not sound normal to me at all.

Looking into past I still think good old rule not to buy new model in its first year of production still stays. Same stuff was with '05 cars as it seems - engine issues, etc, on `06 cars - nothing.

 

I agree with you here. I learned this lesson in 1999 when I bought the first BOSCH ME7 drive-by-wire production car (non-Porsche). Nothing but headaches especially when it came to mods!

 

This guy knows what he's talking about.

https://www.6speedonline.com/forums/2521186-post44.html



I'd say it may be a little soon to make the call. I am leaning heavily towards that it is an issue. Most of the time when someone spends $100,000+ on a car, they would rather stick their head in the sand than acknowledge the issue at hand. So you probably won't hear too much for now. This is the same situation with Audi R8 owners... they simply don't want to believe that their Direct Injection motor is flawed in this regard(they are).

Aaaaaaaaanyways, burning oil won't have too much to do with "carbon" buildup*** and more to do with breaking in a new motor. They just do that. Some cases on here ARE excessive though. Below the low mark in 1600 miles? That's not cool.

***(it's not so much carbon as they are byproducts of gasoline and oil additives. I've had my hands in a few of these engines now and they are a brown baked-on muck, not so much a crusty black soot like straight carbon)

 

Good to know, thanks for the info.

 

I'm usually pretty careful with what I say... so take every word very literally.

"burning oil won't have TOO much to do with "carbon" buildup***"

It will have some affect on this issue.

One more thing... and this should be a PSA to everyone with a DI engine.

Top Tier fuel DOES have some affect on the buildup on your intake valves. Not by way of better fuel cleans the valves better(since fuel doesn't pass over intake valves, duh). But because low grade fuels (your AM/PM type gas stations) have more junk in there that you do not want, does not burn off cleanly during combustion, and then gets recycled past the intake valves(crap).

If you can help it, use non-ethanol gasoline(sorry environment) as ethanol has more "leftovers" than straight fuel. This last line is just word-on-the-street... I'm not a scientist.

 

friend has RS4 and he had to do some major cleaning on his engine from tons of buildup cause DFI... he said he feels sorry for other DFI owners cause while the engine gets better gas mileage and performance their has to be a downside somewhere and the buildup is it..


says in normal engines gas breaks it down but DFI is diff so no gas hitting the sludge.

i guess we need to watch out like that commercial for buildups that "stop us in our tracks"

 

If the blow-by gunk becomes an issue with time, it can be easily cleaned with a Top Engine Cleaner application.

 

So, the choice for shoppers now is IMS failure or gunk?

 

No. That will not clean it off. Solvents do little else but soften it up a thin top layer of the buildup, it won't "fling" off the valves after that. I've been typing too much today to explain... google it.

 

I also think it is fair to say that the engineers at Porsche, audi, and Gm are not idiots. Early adopters like VW and Audi may have caught some of the problems in their teeth, but are we to assume that they designed an engine without testing it? Hardly.
If they build 20 sample engines and run them for 100K miles each under heavy loads, did they somehow miss huge asteroids of carbon on the intake valves?- Hardly.
Do you think that someone figured out this complex situation, in both cause and effect, while reading a message board and eating a Pizza? Hmm...
I am going to avoid any worry and hand wringing until companies stop investing in the DFI technology. There was no real impetus to develop it, so why would they risk so much for so little return? I also have to guess that Porsche learned some lessons from the IMS and RMS failures and the need for thorough engineering.

 

Obviously they tested it and tested it long and hard. Unless your head is in the sand, you are aware of the issues with DI engines along with the facts to go along with it? These issues are in production cars, not a prototype. Yes they were tested, no they did not acknowledge this issue and produced tens of thousands of cars with the motor anyways.

Google "fsi carbon buildup" to get a taste of the reality behind this.

Wait a few more months and then Google "porsche carbon buildup"

Porsche's recycle system is less extensive, but very similar to, Audi's system(3-stage venturi cyclone)

Also read the 14 page Volkswagen AG patent document that lists numerous theories(or is it theorys? that doesn't look right) on how to fix the issue in future cars. None of which have been brought into production yet. The documentation also discusses, in length, the extensive issues this flaw is causing on "all" of the DI motors.

I have had the opportunity to get my hands in a few DI engines from a few different companies(all coked up intake valve issues). Takes an hour to scrub clean one valve after soaking them over night in solvent.

This is a new strain of engine issue.