Direct Injection and build-up issues

[NWS4Guy]

Yes, back to this topic again. I got my new R&T in the mail and there is an article which they also have online already. I'll link and paste it below, but does anyone know of there are any kinds of changes Audi has definitely done to combat this yet?

I bolded the part where Ford (Yes FORD) has addressed this issue apparently in their DI engines already.

http://www.roadandtrack.com/article.asp?section_id=19&article_id=8464



Direct Injection Longevity
We are sure to see more gasoline direct injection and gasoline direct-injection turbocharged engines in the near future. Will these engines be as reliable and trouble-free as the port-injection engines so common today? Will they run hotter and would it be better to use only synthetic oil in these engines? Are there any disadvantages to these engines other than that they cost more?

Richard Gilbert
Souderton, Pennsylvania

Spraying cold gasoline directly into the combustion chamber cools the intake charge, reducing the risk of detonation. This allows a higher compression ratio, blower boost or both, and that is where the extra engine efficiency comes from.

Thus, by itself, DI runs cooler and makes no special requirements on engine materials or longevity, so those parts remain unchanged. From that standpoint, DI engines should prove as reliable as traditional port fuel-injection powerplants. There is some increased complexity to DI, namely the high-pressure fuel pump (over 2000 psi), but considering diesel fuel pumps run at much higher pressures and have proven reliable, it seems logical that gasoline direct-injection pumps will also be reliable.

Adding turbocharging doesn't change DI's cooling effect, but does bring on the secondary conditions of increased weight, parts count and underhood heat retention.

Ford tells us these secondary effects are well controlled in EcoBoost applications. The turbos are small, packaged very low on the engine, water-cooled and don't have much heat-retaining mass. Again, diesel experience is favorable in these regards as well, but we'd keep an eye on any rubber parts near the turbos for heat degradation.

One DI concern is oil residue on the manifold side of the intake valve. Such residue comes from the PCV system and is continuously washed away by gasoline detergents in port fuel-injected engines. In a DI engine, however, the fuel is injected downstream of the intake valve so no valve washing takes place. Ford has found extra oil filtering of the PCV air is required; this is done with a media-type device mounted externally to the engine, typically atop a valve cover. There seem to be no special oil requirements.

If the intake valves aren't washed by DI, the cylinder walls might be. The resulting high ring wear was likely more of an issue in vintage direct-injected gasoline engines (WWII Mercedes aircraft V-12s and 300SL variants come to mind) where the fuel spray was relatively crudely controlled compared to today's electronically governed, multi-strike applications. We'd think there is precious little fuel "waste" to hit the cylinder walls given today's emphasis on reduced emissions and fuel consumption.

Bottom line: We believe the new crop of turbocharged, direct gasoline-injected engines offers a rare jump forward in both power and economy at mainly the cost of higher initial investment. Durability should be on a par with current gasoline engines, with the possible exception of rare additional maintenance to accessories such as the fuel pump, filter media or turbos.

[UGwagen]

Audi has done squat.

Lexus IS350 has toyota's 2nd generation Direct Injection system, which now includes port injection in addition to direct injection (for certain modes of operation)

[Infra]

Audi has done squat.

Lexus IS350 has toyota's 2nd generation Direct Injection system, which now includes port injection in addition to direct injection (for certain modes of operation)

And that was in 2006.

The 4GR-FSE (IS250) doesn't have port injection though. So it seems they might not think it's an issue for the build-up, but rather as a means to keep port injection as an option where it is more efficient than direct injection.

The ECU maps vary the ratio between the two depending on situation. IE, WOT, port injection will mix more fully with the intake air before combustion compared to DI.

[Akatsuki...]

This issue was a major issue int he 2.0T FSI engine, and many have equipped the Catch can. hopefully someone will come with a kit for the S4 and other DI engines, or Audi would implement a port injection to the engines.

[- Jeremy -]

I've seen photos of the inside of an intake manifold from a VW 2.0T engine with around 50,000 miles on it. It was pretty gunked up. The PCV on the 2.0T is fairly crude and the membrane is also prone to rupture. This causes boost to leak back into the crankcase. So there's two problems, really. Dirty manifolds and leaky membranes. Kinky ;)

I'm really surprised that Audi/VW have done so little in regards to buildup in the manifold. Ford is right and it would only take a small, user-serviceable filter before the PCV valve to keep oil from venting with the air. Or even an oil catch-can.

Maybe the aftermarket needs to come to the rescue here... I would definitely buy one if it means keeping my intake manifold clean and sexy.

Get cracking, Mr. Aftermarket!

- Jeremy -

[riegeraudi]

There are catch cans out for purchase and correct me if I am wrong but I don't think they are model specific.
Also from what I understand Audi did introduce the fix that lexus has on their cars on the later 2.0T engines and the new engines in the S4. But it would be great if you guys can ask your mechanics to confirm this as this was given to me by another enthusiast but I have no proof.

[UGwagen]

I've seen photos of the inside of an intake manifold from a VW 2.0T engine with around 50,000 miles on it. It was pretty gunked up. The PCV on the 2.0T is fairly crude and the membrane is also prone to rupture. This causes boost to leak back into the crankcase. So there's two problems, really. Dirty manifolds and leaky membranes. Kinky ;)

I'm really surprised that Audi/VW have done so little in regards to buildup in the manifold. Ford is right and it would only take a small, user-serviceable filter before the PCV valve to keep oil from venting with the air. Or even an oil catch-can.

Maybe the aftermarket needs to come to the rescue here... I would definitely buy one if it means keeping my intake manifold clean and sexy.

Get cracking, Mr. Aftermarket!

- Jeremy -

However, the PCV on the RS4 engine is very complex, which creates 4 vortexes to filter out the fine oil mist----in the end, it still happens.

There are theories that ester addtitives in oils will reduce the gunk. Also a very small amount of fuel actually does hit the intake valves-- so certain fuel additives can help as well.

[Akatsuki...]

There are catch cans out for purchase and correct me if I am wrong but I don't think they are model specific.
Also from what I understand Audi did introduce the fix that lexus has on their cars on the later 2.0T engines and the new engines in the S4. But it would be great if you guys can ask your mechanics to confirm this as this was given to me by another enthusiast but I have no proof.

I would like to know this as well, I heard this rumour, but don't know if it's for sure.

[tgrundke]

Check the 2.0T forums over at vwvortex/fourtitude, there are several major discussions on the subject. I believe some changes were made to the 2nd generation 2.0T to mitigate this issue, but I don't recall what specifically was done nor how effective it has/has not been.

Several of the guys over there have pulled their heads and manually cleaned, but this is only temporary. I do know that I have used VW's OEM cleaner in my 2.0T at around 55k and it made a significant difference in idle and power. I've been running it every 5k now.

[riegeraudi]

I think the best bet is probably to run a catch can for insurance.

[Akatsuki...]

Check the 2.0T forums over at vwvortex/fourtitude, there are several major discussions on the subject. I believe some changes were made to the 2nd generation 2.0T to mitigate this issue, but I don't recall what specifically was done nor how effective it has/has not been.

Several of the guys over there have pulled their heads and manually cleaned, but this is only temporary. I do know that I have used VW's OEM cleaner in my 2.0T at around 55k and it made a significant difference in idle and power. I've been running it every 5k now.

Do you have the part number for this OEM VW Cleaner?

[NWS4Guy]

Resurrecting this!

I spoke with the service dept at my dealership about this. They were a little shy about saying they knew there was an issue with the PCV causing buildup in the intake and specifically on the valves, but said they had heard some people found issues related to this.

I asked if anything like a filter, catch can, or redesign had happened with the B8 S4 engine or even the 2.0T B8 engine to combat this. They said:

"There has been no changes or design to take these deposits into account, nor are there any filters or catch cans in place."

So I guess we might all want to look for a catch can to be safe than sorry?

[tgrundke]

I bought this about 10,000 miles ago and it worked wonders on my 2.0T A3. I know that I ordered it from WorldImpex.com, but I cannot find the part/order information for it anywhere.


Do you have the part number for this OEM VW Cleaner?

[tgrundke]

I definitely recommend reading through the 2.0 FSI thread at vwvortex.com as this has been discussed, tested and beaten to death over there. The long and short of it is that people have tried seafoaming through one of the vacuum lines, they've run the VW engine cleaner, they've pulled the head and manually scrubbed everything...and now there are several options for catch cans.

The consensus, from what I can tell, for the 2.0T at least is this: the original FSI motor has major carbon deposit issues that only a catch can will fix. A lot of people (myself included) have had success using the OEM engine cleaner every 3,000 - 5,000 miles and/or seafoaming through the vac line. This, however, only helps reduce the problem, not eliminate it.

Don't quote me on this, but there also seems to be a belief that the newer TFSI motor corrects a lot of the issues the FSI had, though it's only been on the market for about a year so data is relatively small.


I think the best bet is probably to run a catch can for insurance.

[mellow_sparky]

n00b question: what's a catch can and where/how is it installed?

[NWS4Guy]

n00b question: what's a catch can and where/how is it installed?

Catch can goes after the PCV valve and before the air from it is recirculated back into the intake. It catches vaporized particles of oil and unburned fuel and reside that the PCV circulates back in to be re-burned again. It's an environmental requirement to have PCV since the 60's or so.

Problem is that in FSI cars, the fuel is injected right inside the cylinder, not over the intake valve. Since the valve is never washed with fuel on FSI cars, they tend to build up carbon on the intakes, restricing the airflow/swirl pattern, and robbing power, finally ending up in misfires on the cylinders.

Catch can is like a sponge and takes these out of the airflow, every 10K miles or so you can drain that gunk out of a valve in the bottom of it and let it refill again. They cost anywhere from 100-300 bucks for nice ones - much cheaper than pulling intakes off every 10K miles and cleaning them. Especially since on this car, you have to pull the SC to even do that I bet.

[JMUCI]

I know BSH Performance has three different catch can kits available: Street, Competition, and Race Catch Can Kits.

http://www.bshspeedshop.com/store/home.php?cat=1120

They are for the 2.0T engine, but you could inquire if they would work with the 3.0L engine. I definitely plan to get one of these kits for my 2009 A4 as I have seen and heard way too many horror stories about gunk buildup in Audi/VW Direct Injection engines. I have also heard that the BG Fuel/Air Induction Service gives a good cleaning as well.

http://www.bgfindashop.com/bgservices/fuelair.htm

The video in the link actually specifically shows the service being done on an A4.

[NWS4Guy]

Thanks JMUCI,
I've started a correspondence with Eurojet Racing to ask about our engine. They have already said they have something which will work, they want to see the engine bay and layout to make a bracket for it. I'll have to see about a trip over the mountains to them at some point unless there is someone in the Spokane, WA aera :)

[mellow_sparky]

I think all Audis now come with direct injection - that would be surprising to me that they'd use this across the board without addressing something that is a known problem (i.e. if everyone is coming in at 50K miles with valve problems I'd think they'd address it).

[Akatsuki...]

Here's a Picture of the In and Out Ports of my Catch can when I drained it last night off my 2.0T

http://img.photobucket.com/albums/v521/RNSISPK/DSC00051-1.jpg
http://img.photobucket.com/albums/v521/RNSISPK/DSC00053.jpg

Last picture is a drain I made a while back. I usually drain every 300 km since I'm afraid of freezing issues in the winter

http://img.photobucket.com/albums/v521/RNSISPK/DSC00795.jpg

Look at how bad it is for a 4 cyclinder engine... and imagine your 3.0T engines running even more power and with a larger intake manifold.. how much worse could it be?? [confused]
I'm very interested in getting an S4 for my next car.. but if there isnt an OEM or aftermarket solution to this I don't think I'd come back to VW/Audi...

On the side note..

Instead of a kit, can't someone find the PCV lines on the 3.0T engine and hook up a catch can?

[NWS4Guy]

Great post with pics - this is what you DO NOT want in your intake manifold. EVER. The Catch can, catches this and you can dispose of it properly. If the design worked where it would truly recycle and burn this, it would be ok, but it doesn't for FSI engines :(

[HobbesA5]

Sorry for the mild threadjack, but I notice that the carbon buildup issue is always discussed for forced induction engines, but I've never seen anybody discuss it for the NA 3.2L engine. Since the 3.2 is also an FSI engine, shouldn't it theoretically suffer from the same buildup problem?

[Akatsuki...]

Great post with pics - this is what you DO NOT want in your intake manifold. EVER. The Catch can, catches this and you can dispose of it properly. If the design worked where it would truly recycle and burn this, it would be ok, but it doesn't for FSI engines :(

NP. We're all FSI engines here.. figure I share the wealth of info and pics [:p]
If you're good with DIY [wrench] you can easily get a Carbing Catch can and hook it up yourself. I picked up one for a friend's GTI and he's ordering the PCV plates so I Can hook it up for him. Carbing Catch cans and some Forge catch cans are Universal for people who hook it up in their cars and aren't using specific kits. It may not look as clean or be easy to install, but still does the job for a lot less money, and still does the same thing.

Heres a pic of my catch can
http://img.photobucket.com/albums/v521/RNSISPK/rhmeet-74.jpg


Sorry for the mild threadjack, but I notice that the carbon buildup issue is always discussed for forced induction engines, but I've never seen anybody discuss it for the NA 3.2L engine. Since the 3.2 is also an FSI engine, shouldn't it theoretically suffer from the same buildup problem?

I believe it does. Bobtheoilguy had a thread about a RS4 2007 with major build up issues I think

[HobbesA5]

I believe it does. Bobtheoilguy had a thread about a RS4 2007 with major build up issues I think
Yeah, I had seen that thread. But I haven't seen anything about the 3.2 and was wondering if the V8 in the RS4 had a particular configuration that made the problem worse for it than other NA engines. Searches for other discussions on the topic almost always are centered on turbo FSI engines.

[NWS4Guy]

Sorry for the mild threadjack, but I notice that the carbon buildup issue is always discussed for forced induction engines, but I've never seen anybody discuss it for the NA 3.2L engine. Since the 3.2 is also an FSI engine, shouldn't it theoretically suffer from the same buildup problem?

They absolutely do, FSI is Fuel Stratified Injection (which is direct into the cylinder injection of the fuel), so whether the engine is FI (Forced Induction)or not, it is affected. You only need to look a little to see the complaints:

http://www.audiforums.com/forum/showthread.php?p=1005085

Any car without either some sort of PVC filtration or a secondary injector to bathe the intake valve occasionally to rid it of the deposits will have this issue.

Irony is that Ford's new FSI's don't have the issue, as they have new inline filters for the PVC lines which are replaced every so often instead of a catch can you can install one for the life of the car and drain occasionally.

[nuklearmaniac86]

I have a Hypothesis that a catch can and a "mild" W/M injection system will solve most engine build up problems, even for N/A engines. The catch can to catch the oil blowby and the W/M injection to clean the intake manifold/valves that direct injection can't clean. I'm sure this has been said before and maybe even tested.

BUT I'm not able to test it because I do not have a direct injection vehicle.

[Alkivar]

Sorry for the mild threadjack, but I notice that the carbon buildup issue is always discussed for forced induction engines, but I've never seen anybody discuss it for the NA 3.2L engine. Since the 3.2 is also an FSI engine, shouldn't it theoretically suffer from the same buildup problem?

Hobbes if you end up putting one on your A5, let me know what you used and how much of a bitch it was please... thinking of doing it to mine as well.

[AvantB8]

No one mentioned the BMW engines. My understanding is that the 335 also uses the DI engine, and I have not seen any complaints over there, nothing but the HPF pump...

[L0U]

335s burn oil.....and where there is burnt oil, there is a crankcase vent issue 90% of the time. Forced induction don't seem to see the reduction in hp as much, so it is not as bothersome as in say an rs4.

meth injection may be the ticket for more than just detonation fixes. I think it would be just enough cleaning for the valves as a side benifit.

[- Jeremy -]

335s burn oil.....and where there is burnt oil, there is a crankcase vent issue 90% of the time. Forced induction don't seem to see the reduction in hp as much, so it is not as bothersome as in say an rs4.

meth injection may be the ticket for more than just detonation fixes. I think it would be just enough cleaning for the valves as a side benifit.

Actually, yeah. I recall seeing a post on the GTI forums about this. A guy was using water/meth and he posted pics of his intake manifold. Looked sparkling clean inside. Might not be such a bad idea...

- Jeremy -

[L0U]

or we could fog some nitrous in there every 500kms with all the additional fuel sprayed in with it. I think the meth parts are about the same costs as a top end catch tank. Might be a great solution paired up with a chip tune that runs big boost antways.

[riegeraudi]

Would meth kits be legal and would the extra hp with a tune tip the torque over the limit of what a S-Tronic could take?
I probably going to buy this catch can anyone else interested or any other ones you guys are looking at that could be better?

http://www.42draftdesigns.com/categories/products/catchcans.html

[Akatsuki...]

Meth is legal. Without software you'd prolly have minimal gains, I wouldn't worry about the dsg

[L0U]

catch cans in 20 below freezing can make for a ton of moisture, then ice in them. Once blocked....yer doomed. Keeping them de-iced might be a pain for us canadians.

[riegeraudi]

thanks lou nice to know than we canadians don't really have any options I guess.

[Akatsuki...]

catch cans in 20 below freezing can make for a ton of moisture, then ice in them. Once blocked....yer doomed. Keeping them de-iced might be a pain for us canadians.

Well, if you want to keep your car in tip top shape you have to keep up with the maintenance


thanks lou nice to know than we canadians don't really have any options I guess.

Draining the catch can is easy. I do it every 300km or so. takes about 10 mins.

[riegeraudi]

Well, if you want to keep your car in tip top shape you have to keep up with the maintenance



Draining the catch can is easy. I do it every 300km or so. takes about 10 mins.

So you are in T.O so am I so you have had no problems with it in the winter? Has you ever had it freeze before? If it does freeze will it harm the engine?

[Akatsuki...]

So you are in T.O so am I so you have had no problems with it in the winter? Has you ever had it freeze before? If it does freeze will it harm the engine?

No Issues what so ever.

People had freezing issues cause they didn't drain it consistantly, and had the steelwool version of the catch can, where some steel wool had water in it and froze over time.

If you drain it consistently it shouldn't be an issue. I have a really large catch can, so as long as i drain it every so often it wont be a problem. No issues here.

I'll keep you updated with this as it gets even colder. So far I've been draining every 300 and no issues. Once it stays permanently under 0, I'll drain it every time I come home. I park my car in an underground parking, which stays around 5 degrees, so even if there is a bit of freezing it should melt. After a drive your catch can is usually hot, so it's a good time to drain.

[riegeraudi]

So which one are you using?

[Akatsuki...]

BSH Stg 2 + or as they call it now The competition Can

http://www.bshspeedshop.com/store/product.php?productid=17007&cat=0&page=1

[doctorheine]

btw i had a 2006 gti... went thru 3 pcv valve fixes and 2 crankcase valve fixes in a 2 year span.. by 40 thousand it felt alot slower.... Now i have a NA 3.2 about to hit 30 thousand miles and you can def tell something is not working properly power band wise in the high rpms

[Akatsuki...]

btw i had a 2006 gti... went thru 3 pcv valve fixes and 2 crankcase valve fixes in a 2 year span.. by 40 thousand it felt alot slower.... Now i have a NA 3.2 about to hit 30 thousand miles and you can def tell something is not working properly power band wise in the high rpms

I am gonna give seafoam a try bfore my next oil change.

[Kandiru]

Lease, lease, and lease more!

[L0U]

We are still awaiting the very first case/confirmation that a problem exists in the 3.0T, it has been almost 2 years in now for europe. fingers crossed.

[Akatsuki...]

We are still awaiting the very first case/confirmation that a problem exists in the 3.0T, it has been almost 2 years in now for europe. fingers crossed.


So all good still w/ B8 S4 engine..? no Carbon build up so far?

[NWS4Guy]

None we know of...

[Reverserewind]

There have to be some local cars getting to the stage where they should be checked no? Were there any modifications made to the 3.0 system that would resolve the issue or are we all just hoping it's gone away?

[NWS4Guy]

There have to be some local cars getting to the stage where they should be checked no? Were there any modifications made to the 3.0 system that would resolve the issue or are we all just hoping it's gone away?

It has an enhanced oil recovery system over what was in the 2007 RS4 engines, which supposedly pulls the larger particles out of the air in the crank case, pooling them back into the oil reservoir, as well as Audi purposely increasing the oil temps by about 10F degrees compared to this engine running in earlier versions, which both are measures Audi took to help stave this off. Whether it's helped is still an unknown - since this car was out in EU for 2009 MY, yes there should be some higher mileage 30-40K mile cars which could be checked.

[ISFANDS4]

My car was in with check engine light 2 weeks ago, 7500 miles(mostly Highway) and the result was the replacement of a fuel injector and the cleaning of the remaining...due to carbon build up. It has been 1 week since i got the car back and it feels great but that is a scary feeling. Good thing its under warranty but what happens when one purchases pre-owned down the line and gets this problem.

[L0U]

the fuel injectors have had a few replacements...it is not from carbon though, it is a defect leaker usually.

[Kay15]

I have read on forums where guys will spray the intake filter down with Meth to clean it off and air it out.. thus when the car starts pulling it into the combustion chamber in small dosage to help with the cleaning process?

I have heard of guys using Nitrous on their air filter? Makes sense? I found it weird I am sure the car would choke if you do that?

I think the B8 2.0TFSI may have that issue none that I have heard about just yet tho.

[NWS4Guy]

I have read on forums where guys will spray the intake filter down with Meth to clean it off and air it out.. thus when the car starts pulling it into the combustion chamber in small dosage to help with the cleaning process?

I have heard of guys using Nitrous on their air filter? Makes sense? I found it weird I am sure the car would choke if you do that?

I think the B8 2.0TFSI may have that issue none that I have heard about just yet tho.

Yes getting a meth kit can help with power and cleaning as it's low evap temp allows it to cool the charge air a lot. Many of the NA cars have used Seafoam as well with some good results. In the end with CB, the only real solution if you have it is to pull the manifolds and get in there and clean them.

[ISFANDS4]

That makes me feel better, the service adviser stated it was carbon build up, they are usually misinformed though lol!

[wwhan]

Are there known cases of 2010 S4 3.0T(SC) combustion chamber carbon buildup, other than faulty injectors, yet?

[NWS4Guy]

Are there known cases of 2010 S4 3.0T(SC) combustion chamber carbon buildup, other than faulty injectors, yet?

None that I have seen reported anywhere. The engine has been around for about 2 years now in the A6 here, and the S4 which was an 09 model in EU. I would think that some are bound to have 20-30K miles by now on higher mileage owners. Of course, it might be present, but not found yet, since you have to pull the SC and intake to see.

[L0U]

^^ yep, might be another full year till we hear inclings of a problem. By then it is a non issue if none have showed up. Allmost out of the woods.

[Infra]

Just thought I'd add that some GS350 owners (same 2GR-FSE as in the IS350) have seen carbon buildup even with having 6 DI, 6 PI. Lexus recently acknowledged the problem with the IS250 builup (tend to happen around 40k) and has been giving owners a soak with some GM top engine solvent and a clean up. They have reported that it helps rough idle and engine stalling after highway cruising (RPMs drop from cruising and the engine stalls out, doesn't seem to catch itself to idle while you decelerate). A GS350 owner got the same treatment and claimed it helped.

So, even with detergents washing the intake valves, carbon buildup still seems to be a problem for DI engines. Possible remedies includes adding water to your vacuum line (difference in thermal expansion of the carbon and the intake valves causes the carbon deposits to break off), and driving it like you stole it.

It seems, anecdotally, that the guys who experience the carbon buildup tend to drive "slower".

[LeadToRome]

Since this thread is back at the top: I recently read this (http://www.currysauto.com/Maintenance/bg-service.htm) about BG induction cleaners and was wondering whether it was just a bunch of noise or actually worthwhile. I don't have the knowledge to judge for myself. Anyone?

[NWS4Guy]

So, even with detergents washing the intake valves, carbon buildup still seems to be a problem for DI engines.

The purpose behind DI is that the fuel is injected directly into the cylinder and doesn't wash the intake with the fuel and detergents in the fuel - hence the carbon buildup. What do you mean by your statement?


LeadToRome - Not sure on that one, but many Audi owners with the issue use SeaFoam which does help a good deal if uses regularly (every 6-8 months)

[JimmyBones]

I have heard this side of the theory about carbon build up before and staying tuned for what comes out of this thread because I was told a very different story from our TFM.


Yeah, I had seen that thread. But I haven't seen anything about the 3.2 and was wondering if the V8 in the RS4 had a particular configuration that made the problem worse for it than other NA engines. Searches for other discussions on the topic almost always are centered on turbo FSI engines.

The 3.2 V6s are far worse than the RS4s for carbon build up by just sheer volume. How many 3.2s A4s/A6s were made compared to RS4s? For example, there are probably six or seven 3.2 A6s for every one RS4 at my dealer right now.

The reason that you don't hear about the carbon build up on 3.2s is because most 3.2s are in the family car the A6 where the owner is more worried about taking care of their family than posting on forums.

[NWS4Guy]

Well yea, how many A6 owners track them or dyno or mod them in ANY way? Even RS4 owners ignorant to the issue don't know about it unless they have a CEL, since the atrophy is daily and gradual, the loss in power is over time and not instant, therefore now noticed.

[mellow_sparky]

The purpose behind DI is that the fuel is injected directly into the cylinder and doesn't wash the intake with the fuel and detergents in the fuel - hence the carbon buildup. What do you mean by your statement?



I think what he's talking about the fact that the GS350 has problems with carbon build up and that engine has both direct injection and port injection. So he's suggesting that even though that car has port injectors washing the valves, the car still has a problem with build up.

[NWS4Guy]

I think what he's talking about the fact that the GS350 has problems with carbon build up and that engine has both direct injection and port injection. So he's suggesting that even though that car has port injectors washing the valves, the car still has a problem with build up.
I was thiking this was the case (I know Lexus has a second injector to help wash I heard) but wanted to make sure [:)]

[marty was here]

Since this thread is back at the top: I recently read this (http://www.currysauto.com/Maintenance/bg-service.htm) about BG induction cleaners and was wondering whether it was just a bunch of noise or actually worthwhile. I don't have the knowledge to judge for myself. Anyone?

ive just done this on my k04 2.0t and its made a difference. im not convinced this is a solution to doing a manual scrub (taking the intake off and going to town on it), but it definitely makes a dent.

you cant get around 2 facts. 1. to catch whatever carbon floats around you need a catch can 2. if you have carbon, the only way to completely clean it off, is to take the intake manifold off and do a manual scrub


it sucks but these are the facts of life with carbon buildup, if the 3.0t has it

[Infra]

I was thiking this was the case (I know Lexus has a second injector to help wash I heard) but wanted to make sure [:)]

Yes, that is what I was talking about.

All of this makes me hesitant to plan to keep any DI car long term. Glad my LR2 doesn't have it.

[NWS4Guy]

Yes, that is what I was talking about.

All of this makes me hesitant to plan to keep any DI car long term. Glad my LR2 doesn't have it.

Yes, we'll have to wait and see . Irony, I have an 08 LR2 also [:)]

[Infra]

A little cross posting here...


What has also compounded this problem is the fuel formula itself. Has anybody noticed that small engines (Lawn and snow equip) develop some of the same symptoms? I was having this problem with my lawn mover and my two stroke snow blower for the last couple years that got to the point that I did some research and was advised to add Iso-Heet (isopropanol) to the fuel. After doing so I immediately started to see the problem getting better. Also Amsoil just came out with a new product to help with this exact problem. Attached are links to these products. I suggest adding one of these types of products to the fuel used for small engines. Just make sure the one you use is recommend for that type of engine. Two stroke and four strokes use different isopropanol formulas.

This product can be used in both 2/4 stroke engines and can be found at Walmart - http://www.amazon.com/28202-Iso-HEET-Fuel-line-Antifreeze-Injector/dp/B000V4HC7Y/ref=sr_1_4?s=automotive&ie=UTF8&qid=1276689926&sr=1-4

This the new product from Amsoil - http://www.amsoil.com/storefront/aqs.aspx


Anyone tried this Amsoil product?

[Zed 2.0]

As was explained earlier, fuel additives don't help DI carbon buildup.

[NWS4Guy]

As was explained earlier, fuel additives don't help DI carbon buildup.

Not to mention that what you found is talking about buildup on the pistons heads (and is for small engines to boot), what happens here is due to ERG and PVC particulates with regarrds to vaporized oil and unburned fuel deposits, not old/bad fuel in the system. Fuel brands don't make much difference in the US, they all have roughly the same additives and have had to for over a decade thanks to the EPA. Detergent fuels do no good if the detergent never hits the intake valves to wash the crap off, which is why DI engines can and do get buildup.

[Infra]

Not to mention that what you found is talking about buildup on the pistons heads (and is for small engines to boot), what happens here is due to ERG and PVC particulates with regarrds to vaporized oil and unburned fuel deposits, not old/bad fuel in the system. Fuel brands don't make much difference in the US, they all have roughly the same additives and have had to for over a decade thanks to the EPA. Detergent fuels do no good if the detergent never hits the intake valves to wash the crap off, which is why DI engines can and do get buildup.

Please see below.


EXCESSIVE CARBON BUILDUP

Some late-model engines can develop carbon problems in less than 10,000 miles, as now seen in the 250 motors. There are 2 kinds of deposits, so lets try and not get them confused.

Oil-based carbon deposits - these are the traditional gummy, black one like those sometimes found on intake valves (like the pictures above). They are caused when oil and heat come together.

Carbonaceous deposits - are from fuel. They are also called "cauliflower deposits" because of their resemblence. These deposits are not as thick as oil deposits and are hard, dry, and tougher to remove. Driveability problems can result from them.

The carbon deposits that are causing driveability issues in our engines are from fuel and not oil. A malfunctioning PCV valve will cause oil-based deposits, which is not our problem. An apparent design flaw has caused the 250 motor to have excessive fuel-based carbon deposits, which I do not know yet. All of our motors will have some sort of fuel-based carbon deposits eventually, and will need to be serviced.

Carbon deposits cause driveability problems because fuel vapors can be absorbed into them. That means some of the fuel never reaches the combustion chamber. This results in rough idling when cold, as well as loss of power, surging, and high emissions. Carbon deposits on valves sometimes cause problems in as little as 5,000 miles.

These carbon deposits can be removed by using an additive such as Top Engine Cleaner, but be aware that carbon removers can damage catalytic converters if used too often.

Fuel brand certainly can make a difference, and the major premium fuels all use a slightly different composition of additives that clean up after one another - ie, if you only use shell v-power for the longest time, you will get deposits left behind that techron might clean up.

[NWS4Guy]

Please see below.



Fuel brand certainly can make a difference, and the major premium fuels all use a slightly different composition of additives that clean up after one another - ie, if you only use shell v-power for the longest time, you will get deposits left behind that techron might clean up.

Fuels use detergents to clean intake valves, which are washed with the intake spray, and as mentioned with DI, ther eis no washing, so...it won't matter what blend they use (all US pump fules have to use detergents as mandated by the EPA for over a decade now) it will never hit the intakes on our cars.

[Infra]

Fuels use detergents to clean intake valves, which are washed with the intake spray, and as mentioned with DI, ther eis no washing, so...it won't matter what blend they use (all US pump fules have to use detergents as mandated by the EPA for over a decade now) it will never hit the intakes on our cars.

Audi also uses internal EGR where during the intake cycle you have valve overlap and some of the combustion gases are "sucked" back into the cylinder (and possible around the intake valve). So, it's not totally unfeasible that an additive which removes fuel based deposits *might* help.

Some of the RS4 guys have mentioned running Biosyn 5W-40 oil, but there is not much info on Audizine about their results. Here's something I found on an bobistheoilguy.com


After having the previous valve deposits issues running Audi approved oils, SilverRS4 took matters into his own hands by changing to Biosyn 5W40 and BioPlus, along with pulling the intake manifold to view the intake valves on a regular basis. Here are his results:


I had the manifold off the fourth time about a month ago when there was close to 3000 miles on the Biosyn (. The valves were not clean, but it was more of a thin, oxidized film of oil, rather than thick, gooey, flow-blocking black crud (which was the case after 4000 miles of factory oil, 4000 miles of Mobil 1, and less than 1000 miles of Castrol TXT). I was pleased and will certainly keep using the Biosyn. I am sure Scott could fill you in on the chemistry that makes the build up rate noticably less. I also use the Biosyn fuel conditioner (2 oz) with each fuel fill of Shell gasoline to make sure the injectors stay clean. With the FSI aspect of the 4.2L engine, I believe that sparkly clean valves is just not a realistic expectation - even with Biosyn. But I am happy with how its working thus far. The aspect that really hasn't been discussed is the affect that the oil "contaminated" intake charge has on optimum spark timing. The advanced RS4 ECM's and knock sensors seem particularly sensitive. After endless logging, I have a few cylinders that have timing retarded 4-6 degrees under moderate loads and 9-11 degrees under heavy loads. That is significant. I live in the Midwest and am stuck with Ethanol blended fuel even in the 91-92 octane Tier 1 fuels (Shell included)- that could be part of it, I don't know.

As far as my cleaning method, it was just the old fashion way. In six of the eight cylinders, the intake valves were completely closed, so I just poured in several ounces of carb cleaner right into the intake ports and let the valves soak several hours. Then a majority of the crud comes off with aggressive scraping with an appropriately shaped metal tool. The valve stems block the ability to scrape the area behind them. Vacuum out the mess. Then I poured in fresh solvent and put a small Dremel-type wire brush tool on the end of a cordless drill. Scrub, scrub, scrub. The varnish layer of buildup on the valve surface is very, very hard. This method is limited and removes 90% of the build up at best. The walnut shell blasting would be far better. I have access to such blasting equipment and media, but its ridiculous that I or anyone else has to consider such a chore ...warranty work or not.

[K1speeder]

Does anyone know what the benefits of a fuel conditioner with each fill up would be? Would that help in the 3.0T?

Also, I have a place to get 100 octane fuel at a station that is a ways away from my house. Does anyone think that that would help?

[StratJohn]

On the valves? Nothing. The build-up is from oil, which is recirculated through the areas that fuel is not. In traditional, Non-Direct Injection set ups, the fuel passing over the valves keeps them clean from oil build up. Now, with newer engines, the oil is still present, but the fuel is not. Fuel additives will not help because they basically are not involved with the process anymore!

[Innovator]

Just use B&G cleaning solution injected into a vacuum port (as per instructions)every 10K or so, and that will prevent the sludge from building up in the first place. Once it's built up it's too late for a chemical cleaning. But proactively it works great.

[wwhan]

Like this? http://www.audizine.com/forum/showthread.php/442926-Intrest-in-getting-a-GB-going-for-BG-Intake-track-cleaning-Aparatus-kit?p=6753857#post6753857



http://vimeo.com/3989681

[Innovator]

Like this? http://www.audizine.com/forum/showthread.php/442926-Intrest-in-getting-a-GB-going-for-BG-Intake-track-cleaning-Aparatus-kit?p=6753857#post6753857



http://vimeo.com/3989681

Exactly. That is what we use at my shop, and it is the best preventative medicine out there IMO. Once the buildup is significant though, it won't do much, other than softening the deposits for easier manual cleaning.

[tomh009]

None that I have seen reported anywhere. The engine has been around for about 2 years now in the A6 here, and the S4 which was an 09 model in EU. I would think that some are bound to have 20-30K miles by now on higher mileage owners. Of course, it might be present, but not found yet, since you have to pull the SC and intake to see.

Since this thread has come alive again ... we're now in 2012. what's the word on carbon build-up for the 2010 and 2011 S4 3.0T models so far?

[Innovator]

Has anyone verified that the 3.0 TFSI actually has combustion residue buildup issues like the RS4 and other FSI engines have? Audi has had more than enough time to correct this issue, knowing the problems associated with these direct injection engines.

[Innovator]

[wrench] Beat me by a minute...
Since this thread has come alive again ... we're now in 2012. what's the word on carbon build-up for the 2010 and 2011 S4 3.0T models so far?

[tomh009]

[wrench] Beat me by a minute...
Maybe not the 1/4 mile, but I did have the quick reaction time this time! [drive] [race]

[suffeks]

it is an improvement on the TFSI, especially if you use 504/507 oil

the new 1.8 TFSI is the first audi engine to have an extra injector on the valves to clean that crap up for good, read here: http://www.audiworld.com/news/11/18tfsi/

[mpatel1080]

Has anyone used the 3m Fuel System Tune up Kit? The process looks very similar to the BG product, but at a fraction of the cost. This would be an easy and cost effective DIY every 15k or 20k miles to prevent problems. I have used many 3M products in the past and have never been disappointed in them.

http://solutions.3m.com/wps/portal/3M/en_US/Car/Care/DIY_Projects/Performance/How_to_do_a_Tune-Up/

[Innovator]

Has anyone used the 3m Fuel System Tune up Kit? The process looks very similar to the BG product, but at a fraction of the cost. This would be an easy and cost effective DIY every 15k or 20k miles to prevent problems. I have used many 3M products in the past and have never been disappointed in them.

http://solutions.3m.com/wps/portal/3M/en_US/Car/Care/DIY_Projects/Performance/How_to_do_a_Tune-Up/

You cannot inject anything into the supercharger. It takes the coating off the rotors. On other engines though, nothing works as good as BG

[NWS4Guy]

You cannot inject anything into the supercharger. It takes the coating off the rotors. On other engines though, nothing works as good as BG

They are coated with teflon, so I would be cautious, but the engine already injects the exhaust gases to recirculate back into the intakes by putting it into the supercharger.

[Innovator]

I heard from Eaton it is graphite. Any intake cleaner would dissolve carbon, which is a main component of graphite. It sucks but you'd have to remove the sc to clean the ic and valves.

[Innovator]

I'm sure the intercoolers and intake valves are getting coated just like on the FSI. Maybe a little less but no doubt they are subject to similar deposits. I have seen it first hand on my engine.at 14000 they were coated with deposits.

[mpatel1080]

If this and the BG cleaning would damage the supercharger I can't believe that the dealer service manager would try to push it on my 25k service. Glad I turned it down!

[NWS4Guy]

I'm sure the intercoolers and intake valves are getting coated just like on the FSI. Maybe a little less but no doubt they are subject to similar deposits. I have seen it first hand on my engine.at 14000 they were coated with deposits.


Not as much an issue with the hotter engine oil temps now, and the labrynth oil recovery system is doing a decent job. Not perfect, but not horrible.

http://www.audizine.com/forum/showthread.php/424549-Putting-Carbon-Buildup-to-rest-I-hope?highlight=intake+valve

[Stereodude]

They are coated with teflon, so I would be cautious, but the engine already injects the exhaust gases to recirculate back into the intakes by putting it into the supercharger.

I heard from Eaton it is graphite. Any intake cleaner would dissolve carbon, which is a main component of graphite. It sucks but you'd have to remove the sc to clean the ic and valves.
So you two are saying Eaton coats them with something that can't be cleaned? [confused]

FWIW, Teflon can be pretty durable. For example, when it's used on cookware it can easily be cleaned. It seems really hard to believe it could be graphite, at least in a form that would be easily soluble.

[NWS4Guy]

So you two are saying Eaton coats them with something that can't be cleaned? [confused]

FWIW, Teflon can be pretty durable. For example, when it's used on cookware it can easily be cleaned. It seems really hard to believe it could be graphite, at least in a form that would be easily soluble.

I'll have to dig in order to find the source, but what I was talking about was the screws are teflon coated, the housing is likely just aluminum. The screws have about a human hair distance between the blades when they spin, so there isn't a lot of use in cleaning them, the air is filtered, so the only things that should be introduced into the SC is the recirculated, unburned exhaust gas and the crank ventillation vapors.

[Innovator]

I'll have to dig in order to find the source, but what I was talking about was the screws are teflon coated, the housing is likely just aluminum. The screws have about a human hair distance between the blades when they spin, so there isn't a lot of use in cleaning them, the air is filtered, so the only things that should be introduced into the SC is the recirculated, unburned exhaust gas and the crank ventillation vapors.
Other than the back of the intake valves getting coated and perhaps the intake ports, I am more concerned about the internal intercoolers getting dirty and less effective at heat transfer.

Either way, induction cleaning service uses harsh petroleum distillates, naphtha and ether, and I was told by Eaton it's a big no no. That really sucks, but that's the way it is.Perhaps a fine water mist, like water injection would be ok. I can't see why it would be a problem. If taken apart several engines that had an Aquamist WI systems, and everything was spotless in the engine.

From the B8 study guide..

"Rotors
The two four-vane rotors are set at an angle of 160° and
run on maintenance-free roller bearings. To minimize
wear during the run-in phase, the rotors have a special
graphite-based coating.
This coating also guards against air leakage (rotor to
rotor, rotor to rotor bore) providing better performance."http://www.s4-mtm.com/images/925803_3.0V6TFSIengine.pdf

[BlazinB5]

so several years have gone by, and Audi still has done NOTHING to prevent carbon build up on the newer cars? that's pretty pathetic, since the 2.0T has been having carbon build up issues ever since they came out (and started hitting 50-60,000 miles). the 2.0T engine has been out out since what, 2006? and they still haven't even so much as added a catch can to these cars? i'm beginning to wonder if Audi really cares about the longevity of their motors anymore...

here's what the intake valves of the 2.0T look like after 60k miles:
http://i158.photobucket.com/albums/t92/poopflingr1/My%20intake%20valves/valvesbefore5.jpg

[apexit1]

So did you actually look into this before posting. No signs of any serious build-up for this motor yet.

[BlazinB5]

So did you actually look into this before posting. No signs of any serious build-up for this motor yet.
the problem is, not a lot of people have put 60k miles on their S4 yet, so i doubt we'll really know until then. now if anyone here has 60k on their B8 S4, then that would be real interesting to see.

[svander]

These cars are on their 3rd year (4th in Europe) with many users here with well over 60k on some cars and no reported carbon buildup issues on the 3.0l supercharged engine. You're basically bumping a thread that has NOTHING to do with a 2.0T engine (which has been known to have these issues since 2005).

Good job. [facepalm]

[tgrundke]

The problem with carbon buildup was partially addressed with the 2nd generation EA888 2.0T. The brand new 3rd generation 2.0T that will first debut in the 2013 Q5 goes even further with a dual injection system to try and mitigate the buildup of carbon on the valves.

[silentbob]

The problem with carbon buildup was partially addressed with the 2nd generation EA888 2.0T. The brand new 3rd generation 2.0T that will first debut in the 2013 Q5 goes even further with a dual injection system to try and mitigate the buildup of carbon on the valves.

[:)] Though that's a nice side effect the DI/MPI is mainly because of particle counting on Euro6 Emmission standards [;)]

[apexit1]

There have been a few cars at around 30k torn down and looked at. There was build up but mother to be concerned about. I'm sure if you had searched you would have found that thread...

[Kay15]

Would anyone agree that 100 octane would help clean it out? So what about all this Shell VPower to help reduce carbon build up talk about? I guess that wont help either because of the DI ?

[westwest888]

http://www.youtube.com/watch?v=wsOeO_Wr42A

[korben]

Would anyone agree that 100 octane would help clean it out? So what about all this Shell VPower to help reduce carbon build up talk about? I guess that wont help either because of the DI ?

Not relevant to direct injection as there is no fuel running over the intake valves to clean them.

[BlazinB5]

The problem with carbon buildup was partially addressed with the 2nd generation EA888 2.0T. The brand new 3rd generation 2.0T that will first debut in the 2013 Q5 goes even further with a dual injection system to try and mitigate the buildup of carbon on the valves.
this is good news [up]

There have been a few cars at around 30k torn down and looked at. There was build up but mother to be concerned about. I'm sure if you had searched you would have found that thread...
most of what i found had like 10k miles. i guess i was just quick to assume that all Audi direct injection motors would have the same buildup issue as the 2.0T [rolleyes].

[JimmyBones]

Would anyone agree that 100 octane would help clean it out? So what about all this Shell VPower to help reduce carbon build up talk about? I guess that wont help either because of the DI ?

100 octane is not going to help since the fuel never hits the valves until they go to a MPI AND DI fuel injection system. Shell will keep pimping their fuel additives and avoiding the hard questions like they did in the last Quattro Quarterly mag.

I pulled a lot of superchargers off when the dealers were replacing thermostats regularly and the high mileage 3.0Ts had very little carbon buildup. There of course was some buildup but it was nothing like the V8s (RS4s and S5s) where it took hours to get off. Honestly quit complaining because carbon buildup really doesn't hurt these engines.

[ilspazzaneve]

100 octane is not going to help since the fuel never hits the valves until they go to a MPI AND DI fuel injection system. Shell will keep pimping their fuel additives and avoiding the hard questions like they did in the last Quattro Quarterly mag.

I pulled a lot of superchargers off when the dealers were replacing thermostats regularly and the high mileage 3.0Ts had very little carbon buildup. There of course was some buildup but it was nothing like the V8s (RS4s and S5s) where it took hours to get off. Honestly quit complaining because carbon buildup really doesn't hurt these engines.

Good to hear first hand experience...

Just a counter-point, I would still heartily recommend Shell or any other gasoline with a MMT-free fuel additives package, if you worked on cars in Canada, you would see just how much manganese buildup there is on the exhaust valves as well.

[KurtP]

bump because im searching.

Seems that all of the build up in the engines could be solved by having a tuner disable the EGR system, or using block off plates and disabling the cel code...

[Innovator]

bump because im searching.

Seems that all of the build up in the engines could be solved by having a tuner disable the EGR system, or using block off plates and disabling the cel code...
It's more the pcv system sucking vapors from the valve covers.An elaborate catch can is a better solution.

[L0U]

This thread should be moved to the rs5 spot....hehe. No carbon here, but the rs5 has yet to prove its case.

[KurtP]

It's more the pcv system sucking vapors from the valve covers.An elaborate catch can is a better solution.

Thats what puts the oil into the system, but thats not all bad. Its bad when oil vapors mix with the carbon from the exhaust being recirculated by the EGR that causes the sludge/build up.

Certainly not trying to be argumentative, but why try to use an elaborate catch can system that will never work 100%, and not allow some vapor oiling of the valves instead of a very simple turning off of the emission control valve that is plumbing gas and debris from the exhaust back into the intake?? [confused] Keeping exhaust gas out of the intake track of the engine is a good thing to do regardless of build up.....The oil isnt nearly the enemy that the exhaust gasses are....

Once the EGR is disabled and you dont have the exhaust gasses going into the intake you can tune the car more aggressively and start adding in more timing as well, and then again with a PCV block off.

They are certainly both good to do, but i would think turning off the valve that is plumbing exhaust soot BACK to the intake would take precedence over the PCV system. With the EGR disabled the car will run more timing and get better mileage by a long shot.

[Innovator]

Thats what puts the oil into the system, but thats not all bad. Its bad when oil vapors mix with the carbon from the exhaust being recirculated by the EGR that causes the sludge/build up.

Certainly not trying to be argumentative, but why try to use an elaborate catch can system that will never work 100%, and not allow some vapor oiling of the valves instead of a very simple turning off of the emission control valve that is plumbing gas and debris from the exhaust back into the intake?? [confused] Keeping exhaust gas out of the intake track of the engine is a good thing to do regardless of build up.....The oil isnt nearly the enemy that the exhaust gasses are....

Once the EGR is disabled and you dont have the exhaust gasses going into the intake you can tune the car more aggressively and start adding in more timing as well, and then again with a PCV block off.

They are certainly both good to do, but i would think turning off the valve that is plumbing exhaust soot BACK to the intake would take precedence over the PCV system. With the EGR disabled the car will run more timing and get better mileage by a long shot.
The oil vapors coat the intake ports and valves, and that causes the exhaust gases to stick and accumulate.

[KurtP]

The oil vapors coat the intake ports and valves, and that causes the exhaust gases to stick and accumulate.

Thats what I said in the first line....Im trying to figure out why we want to catch oil vapors before we stop the car from recirculating carbon particulate loaded exhaust gas back into the intake stream. [confused]

[Innovator]

Because it isn't legal to bypass the EGR, and no tuner would Implement it.

[Thomas@TAI-VW]

There is no EGR on these engines,and not on any VAG engine I can think of. They use adjustable excessive cam overlap to perform the cold startup Exhaust gas burning. The carbon,if any is from oil vapor.

[*Blue-Angel*]

so several years have gone by, and Audi still has done NOTHING to prevent carbon build up on the newer cars? that's pretty pathetic, since the 2.0T has been having carbon build up issues ever since they came out (and started hitting 50-60,000 miles). the 2.0T engine has been out out since what, 2006? and they still haven't even so much as added a catch can to these cars? i'm beginning to wonder if Audi really cares about the longevity of their motors anymore...

here's what the intake valves of the 2.0T look like after 60k miles:
http://i158.photobucket.com/albums/t92/poopflingr1/My%20intake%20valves/valvesbefore5.jpg

The fact that these cars arent made with dual injection motors baffles me.

[KurtP]

Because it isn't legal to bypass the EGR, and no tuner would Implement it.


There is no EGR on these engines,and not on any VAG engine I can think of. They use adjustable excessive cam overlap to perform the cold startup Exhaust gas burning. The carbon,if any is from oil vapor.

[facepalm]

you mean the same tuners that bypass catalyst codes, makes exhausts "for the purpose of increasing noise", remove speed limiters, and making "power adders purposed for increasing velocity"??

EGR valves are in tons of VAG motors. In VW its usually the "N18 valve" and sometimes called the "kombi" or "combi" valve in audi's. Its there.

You dont get carbon build up from oil vapors alone. The oil vapors mix with carbon and other particulates and/or dirt to form the gunk and sludge that builds up.

Think about the build up you find in your exhaust when you change your pipes out. That black build up is the same gas that is getting recirculated by the EGR into the intake stream where it mixes with PCV oil vapors to form that sludge. You can run more a tangibly more aggressive timing curve by shutting this thing off or blocking it off and running a catch can or Air Oil separator because you get a much much cleaner burn in the combustion chamber. The knock threshold gets pushed noticeably to the right in tuning, giving you a higher degree of safety/power.

[Innovator]

No argument.

[Thomas@TAI-VW]

That Kombi valve has nothing to do with EGR,those are for the SAI system. There are no EGR valves on VAG motors that I know of. RE-Burning of exhaust gasses is done through adjustable camshaft overlap. That is the prupose for the VVT systems in VAG cars. The Kombi valves allow fresh air to enter the exhaust system from the SAI pump,there is no exhaust gas running through those.

[KurtP]

That Kombi valve has nothing to do with EGR,those are for the SAI system. There are no EGR valves on VAG motors that I know of. RE-Burning of exhaust gasses is done through adjustable camshaft overlap. That is the prupose for the VVT systems in VAG cars. The Kombi valves allow fresh air to enter the exhaust system from the SAI pump,there is no exhaust gas running through those.


Based on that, where would you surmise the carbon build up is coming from? Meaning, if there isn't carbon gas being recirculated, where is it being introduced to the oil coming from the PCV system?

[NWS4Guy]

Based on that, where would you surmise the carbon build up is coming from? Meaning, if there isn't carbon gas being recirculated, where is it being introduced to the oil coming from the PCV system?

Start on page 8 and learn. PCV feeds oil laden air from the crankcase into the bottom of the supercharger, to be compressed with fresh air, then through the intercoolers, and down onto the backs of the intake valves. Heat bakes this on over time, and enough heat will bake it off. Those cars with the big carbon issues are daily drivers which see very short commutes and rarely if ever are driven long enough to get the engine nice and hot to bake the deposits off (since there is a lack of an injector to wash this).

http://www.s4-mtm.com/images/925803_3.0V6TFSIengine.pdf

[Thomas@TAI-VW]

I just caught something,I am wrong on the S4 engine,they omitted the exhaust cam adjuster and it says there is a internal exhaust gas recirculation system,however they do not elaborate on it. I have not seen any EGR valves however.

[KurtP]

Start on page 8 and learn. PCV feeds oil laden air from the crankcase into the bottom of the supercharger, to be compressed with fresh air, then through the intercoolers, and down onto the backs of the intake valves. Heat bakes this on over time, and enough heat will bake it off. Those cars with the big carbon issues are daily drivers which see very short commutes and rarely if ever are driven long enough to get the engine nice and hot to bake the deposits off (since there is a lack of an injector to wash this).

http://www.s4-mtm.com/images/925803_3.0V6TFSIengine.pdf

Thanks for the link. Lots of good info there. Looking at the design of the blower in the chart, it seems the PCV port, as you mentioned is the only secondary intake port to the blower, so I wonder if/where there is another air feed to the PCV where carbon introduces itself to the system?

I dont think the oil is going to pick up sufficient carbon content in the crank case to do what you are seeing on your valves. If it did, it wouldnt be able to reach a vapor form to travel through the PCV system. In order to do what is happening to get the sludge being seen, carbon is being introduced in the intake track and then mixed with the oil vapors. The carbon gas sticks to the oil from the PCV and gets baked on by heat....running the motor hard and getting a more complete burn would help prevent some build up i would guess, but it would take very extreme heat to simply "bake it" back off once its set in.


Id be interested in any of the tuners apr/awe/giac have any insight/info/comments on the whole topic....Especially with the notion that removing a PCV or EGR type system really helps with performance in tuning.

[DeanMTL]

Just had my 2011 S4 with 18,000 km throw up a CEL, drive like it was in limp mode. Dealer told me it was due to carbon buildup and it spent three days in the shop under warranty. I was also told the warranty for this has been extended to 2020 (9 years).

[xcnovanrunner]

I recently got a letter from Audi of America stating that Audi has extended the factory warranty for carbon build up. I'll see if I can create a PDF and post it up here for everyone else to see.

Sent from my Nokia using Tapatalk

[helix139]

I recently got a letter from Audi of America stating that Audi has extended the factory warranty for carbon build up. I'll see if I can create a PDF and post it up here for everyone else to see.

Sent from my Nokia using Tapatalk

No need. Old news.

[Stereodude]

Just had my 2011 S4 with 18,000 km throw up a CEL, drive like it was in limp mode. Dealer told me it was due to carbon buildup and it spent three days in the shop under warranty. I was also told the warranty for this has been extended to 2020 (9 years).That's not the same carbon buildup that this thread is about. The CEL isn't from carbon on the valves.

[bokiboki]

I know it's an old thread but what is the carbon build-up in question here that the warranty for is extended to 2020 (or 9 years)-if it's not for the intake valves?