Anyone aware of this problem with the DFI's ? Excessive carbon b/u on intake valves, stems etc...
It was a big problem on the VAG DFI's, and my recent B7 RS4 AUDI
Has porsche dealt with this problem with their oil mist seperator....

 

I do not think anyone has dealt with this subject. DFI engines are becoming the norm as auto companies try to reduce fuel consumption and emissions. I think that the big $$$ tune up in the future will be to clean up the intake area of cars as the airflow ( and with that, power) is reduced. I doubt the oil /air separator will solve the problem as ther will still be oily crankcase air being recycled into the intake of the engine. Perhaps auto companies will need to come up with a solvent injection system for the intake manifold area ( like the urea injection for the exhaust in Diesel engines).

 

Top Engine Cleaner.

 

Top engine cleaner ?
Who manufactures this product ? What are their claims ? Is their widespread use of it >? Do you use it adias ?
Are porsche aware of the potential problems ?
Its an absolute hot topic for the AUDI DFI's

 

So... how do you use Top Engine Cleaner? Adding it to the fuel will do nothing for a DI engine. Using it to clean up an engine intake area properly will mean taking apart the induction assembly... not a procedure for most folks. This sounds like an expensive "tune up".

 

I have not heard of any 997.2 DFI engine with intake gunk. Should there be an issue, I learned that a std GM Top Cleaner can be injected into the intake via a vacuum hose to clean the intake.

 

adias - you've had a bunch of really impressive posts lately. Can only speak for me, but I really appreciate it. Thanks for passing along your research.
Tom

 

Interesting thread. I've also read that that products like TEC and SeaFoam could help if used regularly, before the buildup gets too bad.

Would anyone have any idea about what a "regular" interval would be? (5K miles? 10K miles?) and also has anyone else used such a measure to avoid having to deal with carbon deposits down the road? Or am I just being paranoid?

A can of SeaFoam is something like $10, so I am all for it once a year if it can help.

T.

 

If needed at all... it will be a lot more time than that. Cars with the DFI engine and with 50k miles have not shown this 'phantom' issue.

 

Porsche's history has primarily been as a engineering design consultant to industries worldwide in various fields, not just automotive. Direct injection has been around since World War II. Every engine designer knows the trade-offs, but of course not all firms carry out designs from conception to production as well as others.

Not only are Porsche aware of this issue with direct injection, the odds are very good they had been called in by several manufacturers to find cost-effective solutions long before they released their own DFI engines. We'll never know details since such engineering contracts come with a non-disclosure agreement, but we do know they know as much as anyone in the business.

As Adias pointed out, all the problems reported so far have been with non-Porsche engines.

Gary