SoCalJ

I was just wondering about the whole carbon issue that has been a concern for our direct injection 4.2's. Does driving at nice constant speed for a long period of time help prevent or clean out the deposits? (75mph for 45 minutes) or is it the aggressive high revving that is more effective? ( 1 or 2 redline runs once or twice a week)
I have been faithful with only using 91 Shell or Cheveron gas, however Arco sometimes tempts me with their low price and my oil changes have been every 5-8k miles with Mobil OW-40.
Any helpful information or first hand experience would be appreciated. Thanks

C-ked

I was having brand new plugs foul within 3k miles. I used seafoam and aggressive driving... One can, follow the instructions, wait 2 weeks, then another can. It seemed to cure the fouling problem, otherwise the car runs pretty smooth.. I also found a 3m product I'm going to try. works similar to seafoam

TSHong

If you can find BG44K in your area, try it. It's a great product. Comes in a metal can and will damage your paint if you don't clean it off.

greginfinity

Lucky for me I don't have stupid FSI, so I pour gas all over the valves with each fire of the injectors!

I have tried to educate myself on this issue by reading about it on numerous engines and am still not convinced that anything other than a proper valve cleaning really solves anything. The basics of the problem at hand are:

1) FSI engines have no fluid cleaning the valves (except for newer engine designs that have an aux injector to do just that).
2) Air pollution requirements require that some vapors be routed into the combustion chamber.

This means that some oily residue gets sucked into the intake track, and coat the valves. It likely gets baked onto the valves at high temperature. I am not convinced that running the engine hard actually "burns" anything off the valves. I also doubt that running a little bit of seafoam over the valves does anything either. Some people install catch cans, but I don't think this has been 100% successful in preventing buildup either.

I don't really have any simple solutions for preventative maintenance but I think the only real effective thing would be to either walnut blast the valves in the car, or disassemble the head and clean each valve.

I don't think you should really concern yourself with it either, I don't see a lot of people complaining about the issue with this car. Other Audis, definitely have an issue (RS4, A6 with 3.2 etc)

mishar

PFI won't prevent carbon deposits if engine builds up extensive pressure in the chrankcase. It can make it even worse if low quality fuel is used.

EHLO

I've used Seafoam, but looking down the spark plug hole with a 45 degree angled Borescope revealed very little buildup at over 50K miles anyways.

I found some information in the study guide, starting at page 10;
Crankcase Ventilation
Blow-by gases created during the combustion process must be ventilated from the crankcase. Excess blow-by can cause sludge and acids, leading to coking of the intake valves.

...and at page 11;
When the engine is running at very low load but at a very high RPM, the piston rings can begin to flutter. The blow- by gas pressure is very high and the fine oil separator
is unable to operate at its peak efficiency. At this point, the by-pass valve opens and a fraction of the blow-by gas flows to the intake manifold untreated. (See bottom illustration.)

So make sure your Fine Oil Separator is working correctly, don't run the engine at low load and high RPM, and as mishar notes, use high quality (and high octane) fuel so the variable valve timing isn't dipping into an area that allows blow back.

Study guide;
http://www.1stcallhosting.com/tech/a...cc+V10+FSI.pdf

Jake-AudiUSAParts

+1! I have been using the BG products, including the 44K in all of my non direct injected vehicles and my families’ cars for many years and have had great results. The 44K is very powerful stuff and is only needed once a year, for regular maintenance I use the CF5. Unfortunately, as many forum members will tell you, there isn't much you can do for a direct injected engine when it comes to valve fouling/carbon build-up. With that said I would still recommend the BG fuel treatment products even in FSI engines as they help keep the entire fuel system clean and working properly, including the very expensive injectors themselves. Most BG treatments come as a kit with either a "Fuel dryer" or an” oil additive”, both of these can be beneficial to your engine and I use both at every oil change and sometimes in between. Here in Oregon we are notorious for having low quality, "dirty" gas with lots of water in it so a fuel system cleaner plus a dryer is always a good idea. I know it must sound like I work for BG but I promise you, I do not, I just think they make a great product and I notice a performance increase immediately after using their products.

C-ked

Bg44 was something I researched as well, it's hard to find a retailer here in Philly. I only know of one shop for sure that has it. And that's a vw dealership. If you goto the bg44 website you'll find a retailer.. Just call and confirm they have the right product. I had to make several calls to find the right shop with the right tool.

SoCalJ

There a few auctions on ebay as well for BG products. Thanks

tx170754

It can also be found on Amazon