Carbon Buildup -- tech start, not whining

[usedtobefast]

I have seen alot about the CB problem on here, but I would like to see some real technical analysis beyond the "it's the FSI design."

So here's a start:

We know the direct injection eliminates the washing action of the fuel spray.

The buildup is coming from somewhere, not thin air.

So, where?

Is it valve guides? Common on a lot of engines, but seems less likely in a presurized engine and would likely come with higher oil consumption.

Is it oil coming past the turbo seals? Seen alot of that on old 930s.

Is it a result of the crankcase ventilation system? Seems like breathing only air would result in no buildup.

How does the synthetic oil figure into all of this?

If we knew the origin, perhaps there is a way to avoid or at least delay the problem.

I have seen no fix info posted on any Audi site. Perhaps we can get some real hands on tech people to come to our aid. Let's start some useful information.

BTW, I have been working on cars 49 years, and built/raced 911s for 20 plus years. I just don't want to take my Audi apart.

[RedS-line]

the carbon builds up on the valves as a byproduct of the combustion process, i believe. the BG induction service cleans this but does not fix the problem. i got this service but i did not notice any driving difference and did not check my valves to report before and after. vvortex forum has more info on this topic.

[bblume]

best fix I can think of is some kind of catch can or vent to atmosphere(meaning the problem lies with the OEM Pcv setup), and a w/m kit to keep it clean once it is cleaned by seafoam or a complete break down and chip-away process (some of these or described on the 'tex)
I don't think italian tune-ups work on these fsi motors because all of the oil vapors are returned right back onto the intake valves and then they cake on because of the heat....hence the catchcan that disallows said vapors from being thrown back into the motor!!!

[Tanner]

The deposits are left behond from the blowby gases.

I've read of several posts on rs246 and rs4.com and solvents hardly put a dent on this stuff. Once it's cooked on the intake valves, there's pretty well no solvents that will remove this stuff that I'm aware of. You need to pull the stuff apart and scrub the stuff off. The local dealer here uses basically a spindly brush which is basically plastic bristles (something similar to those zip ties) and on a drill and beat away at the stuff while vacuuming the stuff away.

There are several catch-cans out there but one product that really gets my interest is a filter from MANN+HUMMEL....

http://www.mann-hummel.com/group/upl...BLAXUCmOK5.pdf

Thinking using this along side downward from the stock setup and that should pretty well catch all of the oil vapour.

[usedtobefast]

Aha. Some real info.

From a theoretical, logical standpoint, regarding the naturally aspirated engines, I can see lots of sources for the buildup when it's FSI. These engines will have significantly more overlap in their cam duration and have blowback as well as other sources. Less likely a source on the 2.0 FSI since turbo engines have less overlap in their milder timing and have turbo pressure starting at a relatively low rpm.

I have thought that on the 2.0 at least, the crankcase fumes are the most likely culprit, but not necessarily the sole culprit.

I wonder if it may be related to oil consumption as well. Posts re the 2.0 indicate some cars seem to have no problem, others sooner rather than later. Posts also indicate a wide range in oil consumption. I wonder if they are related. If so, my car uses no measurable amount of oil between the 5,000 mile changes. Maybe luck is with me.

Tanner pointed out one source for a catch can. Thank you. Can anyone who has addressed this issue give me more input on this solution?

[usedtobefast]

There are several catch-cans out there but one product that really gets my interest is a filter from MANN+HUMMEL....

http://www.mann-hummel.com/group/upl...BLAXUCmOK5.pdf

Thinking using this along side downward from the stock setup and that should pretty well catch all of the oil vapour.

I think this would be a great help. Could you keep me posted if you install one? And on what car? I would use on 2.0FSI.

[bblume]

search BSH stg II catchcan...NINJA edit....just the amount of liquid you draw out of the catchcan in
the winter months is enough to feel validated on a PCV solution purchase

[Tanner]

I haven't done anything on mine, it's coming around to about 97,000km on it. If I ever have to get a good scrubbing done on my car, I'd seriously consider doing something to help prevent the issue but nothing at this time.

[Nikoman]

I just got the BG Induction Service done at the dealer, I'll try to take some borescope pics and post soon. It's going to my local tuner, GRD, to get the cam follower changed along with an APR HPFP. I have 46.5k miles btw.

[bblume]

^^^^interested...this will be on my list soon as I' just crossed 80k.
Maybe pull the whole thing and chip away at it with a chisel if this BG induction doesn't prove effective.

[illegitimus]

The deposits are left behond from the blowby gases.

I've read of several posts on rs246 and rs4.com and solvents hardly put a dent on this stuff. Once it's cooked on the intake valves, there's pretty well no solvents that will remove this stuff that I'm aware of. You need to pull the stuff apart and scrub the stuff off. The local dealer here uses basically a spindly brush which is basically plastic bristles (something similar to those zip ties) and on a drill and beat away at the stuff while vacuuming the stuff away.

There are several catch-cans out there but one product that really gets my interest is a filter from MANN+HUMMEL....

http://www.mann-hummel.com/group/upl...BLAXUCmOK5.pdf

Thinking using this along side downward from the stock setup and that should pretty well catch all of the oil vapour.

I definitely like this setup as opposed to a simple catch can. It looks like the original PCV valve does not need to be removed in this case and this setup simply compliments the oem system. Am I correct? Anybody had installed this on our cars, I wonder?

[aelim]

As tanner mentioned regarding the catch can, I have recently installed the BSH stage 2 CC(less than 2 wks).
It has been working wonders for me since then and the amount of blow by and other such crap. I have emptied the can on a weekly basis, the amount of condensation and engine contaminants is a amazing.
Hopefully this will help resolve some of the build ups with regular seafoam cleaning?

[Tanner]

If I ever get around to doing something, I'll probably do what somebody suggested, incorporate the MANN+HUMMEL filter alongside with the existing PCV, or more like what comes out of the PCV gets routed into this filter then back into the engine. PCV will get most of it as we know and this filter will catch everything else that the PCV failed to contain. And replace the filter everytime the oil gets changed.

[yimstab7]

whats the best way to clean it? i am a noob can somone enlighten me about catch cans and bg induction service?

[TheHeggi]

whats the best way to clean it? i am a noob can somone enlighten me about catch cans and bg induction service?

I'm starting to understand why people push the search feature so much now. If you are concerned, please search the topic in the forum search feature. There is plenty of info to read through.

[a4dc89]

I like the sound of the catch can idea. So many things to fix up on this car to make it real reliable: Fuel pump follower, DV, PCV and now carbon build up.

[Tanner]

Best way to clean it... dealer. Pull off the top and they basically go in with a brush and scrub off the crap and vacuum it out. Very labour intensive and not cheap especially if you're off warranty.

I like the sound of the catch can idea. So many things to fix up on this car to make it real reliable: Fuel pump follower, DV, PCV and now carbon build up.

I don't really think that these issues really make the car unreliable especially for a high mileage vehicle. Cam follower, we all know now to have it checked once in a while to prevent permanent damage to the HPFP. DV, nothing new really here, the diaphragms will fail, just get the one without the diaphragm. PCV, never had any issue with mine. It's just the carbon buildup that's an issue with *ALL* FSI engines unless there's some sort of port injector that sprays a bit of fuel on the intake valves to keep it clean, like what Toyota is doing.

[rings65]

So, I see some posts where people have the issue (and needed to have work done) at 30,000 miles, and other people who have 80,000 miles on the clock and don't seem to be having problems (that's not to say they wouldn't have carbon buildup). Any ideas why it hits some people harder/earlier (sometimes a lot) than others?

[Tanner]

Oil being used and driving style I think are the major factors. Maybe type of fuel (though I believe that there isn't out there that says that fuel being used has a direct impact to the buildup).

[jmars]

I'd love to hear some more on the Mann/Hummel filter. My cam was just replaced under warranty and now I want to be proactive on this carbon build up. Are there anymore members that have this set up? Any other companies making something similiar? I see BSH but is that it?

This website make me nervous and broke!