Thread: Audi FSI Engine Carbon Build-up Megathread

This thread serves to index all the threads related to carbon build-up in the intake manifold of Audi FSI engines of -any- model. It's just here as a place holder index of these threads as a requisite of judging scope of the problem and raising awareness. Please read the threads for more details of this problem...

I've tried to tag content as much as possible. With either PICS where there is photographic evidence or CONCERN where there is discussion surrounding concern of the issue.

B7/B8 A4:
Carbon Build up cleaning?? CONCERN
Carbon Buildup PICS
BG44k for controlling carbon buildup ... CONCERN
Carbon Buildup ** tech start, not whining CONCERN
Carbon Build Up - 2008 Audi A4 3.2L EXPERIENCE
Audi = carbon buildup?!? CONCERN EXTERNAL
Need input / carbon buildup on intake valves EXPERIENCE EXTERNAL
2.0T FSI Carbon build up. PICS EXTERNAL
Theory on combating carbon buildup: CONCERN
Redline Speed Worx: Cylinder Head Carbon Build Up Sea Foam Service Limitations PICS
carbon build up question CONCERN
Carbon Build Up CONCERN
Shell fuel for B8 2.0T ? CONCERN
2007 Audi A4 3.2FSI - @ 147k carbon/deposit buildup PICS

S4 3.0:
Direct Injection and build-up issues CONCERN
Catch Can CONCERN

A5/S5:
S5 FSI engines doomed due to intake manifold carbon build-up ? CONCERN
Audi A5 3.2 v6 FSI - carbon issues? CONCERN EXTERNAL
Carbon Build up at 35K PICS

A6 3.2:
Carbon buildup CEL TSB Update EXPERIENCE EXTERNAL

RS4:
RS4: Intake Manifold Carbon Build-Up & Clean Up PICS
RS4: ** PART 2 ** Intake Manifold Carbon Build-Up & Clean U PICS
RS4 only 263whp flat from 6k rpm ?!?! PICS
Sea Foam useage? CONCERN
Cost to Clean Carbon? CONCERN
My RS4 under the knife... PICS
Fuel adatives.... PICS EXTERNAL
RS4 owners READ this! CONCERN
RS4 Owners Step in. What I feel to be very important. It's a long read. CONCERN
Need help, RS4 in shop for MILs, how does valve cleaning get authorized? CONCERN
Dyno after port, polish, manifold flap removal PICS EXTERNAL
Dyno info for the day... PICS EXTERNAL
***** Official Carbon Build-Up Thread ***** POLL
Carbon Build-up 101? CONCERN
KryptoniK's RS4 PES S/C Build PICS
2008 RS4 Carbon buildup EXPERIENCE EXTERNAL
FSI Engines - Audi RS4 Engine Oil-Related Deposits PICS EXTERNAL
RS4 B7 Carbon Buildup CONCERN EXTERNAL
Update on carbon cleaning.... EXPERIENCE EXTERNAL
My RS4 Carbon Build-up Story PICS
RS4 Supercharger Project Has Started Pics PICS
RS4 carbon cleaning finished !!!!!!! EXPERIENCE PICS
RS4 Piston Damage from Carbon Build-up PICS
RS4 : to prevent carbon build up, i think this product will work. CONCERN
RS4 inspected by AOA for CB EXPERIENCE
my RS4 needs help CONCERN
Throwin' Codes at 9900 miles - 2008 RS4 EXPERIENCE
Thinking of buying an RSs4. Does it have carbon problems CONCERN
B6 S4 paid off... 20K to put down on used Rs4 with lower miles.. Cant do it! CONCERN
My RS4 dyno numbers... PICS

R8 4.2:
FSI Carbon Buildup CONCERN

TT Mk2:
carbon buildup problem with TFSI - serious worry CONCERN EXTERNAL

You can PM me any additions you have to keep the thread clean if you like..


How Direct Injection (FSI) Works
I was sent the following videos that do an excellent job of describing how direct injection works. They're mostly technology promo shorts that completely ignore the downside of build-up but still good overviews. For the non-tech inclined, the difference between what these videos describe and "standard" port injection is that in port injection, fuel enters the through the intake valves giving a cleansing effect to any build-up (from the exhaust recirculation) that may be there. Thanks to Andyuk911 for these links!

Bosche Promo (for the same management unit found in the RS4)
ASNU (injector diagnostic manufacturer)
GM Promo

Problem Synopsis
The general consensus is that the build-up that forms under normal operation can decrease engine power within a relatively low amount of milage. Most anecdotal evidence shows that when the intake valves are cleaned, engine returns to spec-rated horsepower and torque. This build-up is thought to affect power in as little as 10,000 miles though few people have routinely removed their intake manifolds to document the build-up progress.

Variables
A wide-range of variables have been included in reports of build-up. A common theme is that this occurs despite tier 1 fuel and Audi recommended oils. Reports have also come in from all over the world, suggesting it's not localized to any particular region's fuel, environment or emission standards.

Indicators
Severe cases of build-up can potentially trip misfire CEL codes though in most cases, the car simply produces less power and does not indicate malfunction. Those that have cleaned their intake manifolds explain a burst of acceleration under WOT at 6k RPMs (2nd gear)(applies to RS4/R8 4.2). Dyno results for affected cars seem to be anywhere up to 40hp below quoted stock HP on the 4.2 V8 FSI engine.

Solutions
To remove build-up, only a manual physical cleaning of the intake valves and vanes has shown to be able to completely remove the carbon of which Audi will not warrant unless there are continual misfires occuring. To prevent the issue from reoccurring, oil catch cans are the most frequently raised potential solution in addition to methanol injection. At least one thread has cited both of these systems were in-use and build-up still occurred.

There are a number of temporary cleaning solutions that are available. The effectiveness of these has not been discussed. Some of these include: BG 44k and Direct Injection Power 3. Audi's solution is a fuel additive to clean the injector ports, though this has been shown to have little to no effect on carbon build-up on the intake valves.

Audi has not yet acknowledged the extent of the carbon build-up problem. There is a letter that has been created by a forum member to Audi in this thread:

Official Letter to Audi of America Executive Vice President...Thoughts?

This was much needed. Thank you.

I would imagine they are having issues also in the new A6... but maybe not enough people on the zine with that model A6 to bring up the problem.

Very good. Thanks.

I am requesting that this thread becomes a sticky.

More and more members that own or are looking to own (T)FSI cars are concerned with carbon build up and its effects.

If anyone has been through this ordeal and has photos or any info related carbon build up, this is the place to post such.

You can also post if you have done something which has minimized or even eliminated CB.

Those that have already had their intake manifold removed and discovered CB should post the following:

Vehicle Make/Model.
Location: What state/country the car was driven primarily.
Mileage/Date in which CB was discovered.
Oil used.
Oil Change Interval.
Fuel Used.
How short/long are your trips on average.


Before I post my info, this is how VW/Audi feels about it:

VW patent acknowledging the intake valve deposit issue

Directly from the technical staff of VAG is complete acknowledgment of the FSI intake valve deposit issue, and it's impacts, including: decreased performance, misfires, catalytic converter damage ... etc.


"Gasoline engines with direct injection of the fuel into the combustion chamber, i.e., not into the intake port, suffer especially from the problem of the formation of carbon deposits on components. Carbon deposits form especially in the neck region of intake valves. A more exact analysis of how these carbon deposits form leads to the following result: Oil and fuel constituents first form a sticky coating on the components. These constituents are chiefly long-chain and branched-chain hydrocarbons, i.e., the low-volatility components of oil and fuel. Aromatic compounds adhere especially well. This sticky base coating serves as a base for the deposition of soot particles. This results in a porous surface, in which oil and fuel particles in turn become embedded. This process is a circular process, by which the coating thickness of the carbon deposits continuously increases. Especially in the area of the intake valves, the deposits originate from blowby gases and from internal and external exhaust gas recirculation, and in this process, the blowby gasses and the recirculated exhaust gas come into direct contact with the intake valve."

"Especially in the area of the neck of the intake valves, excessive carbon deposits have extremely negative effects for the following reasons: In the case of Otto direct injectors, the successful ignition of the stratified charge depends to a great extent on the correct development of the internal cylinder flow, which ensures reliable transport of the injected fuel to the spark plug to guarantee reliable ignition at the spark plug. However, a coating of carbon deposits in the neck region of the intake valve may interfere so strongly with the tumble flow that ignition failures may occur there as a result. Under certain circumstances, however, ignition failures can lead to irreversible damage of a catalytic converter installed in the exhaust gas tract for purifying the exhaust gas. Furthermore, the coating of carbon deposits in the neck region of the intake valve causes flow resistance, which can lead to significant performance losses due to insufficient cylinder filling, especially in the upper load and speed range of the internal combustion engine. In addition, the carbon deposits in the neck region of the intake valve may prevent correct valve closing, which leads to compression losses and thus sporadic ignition failures. This in turn could irreversibly damage the catalytic converter. There is the potential for small particles to break away from the coating of carbon deposits in the neck region of the intake valve and get into the catalytic converter. These hot particles may then cause secondary reaction and corresponding local damage of the catalytic converter. For example, a hole may be burned in the structure of the catalytic converter."

"Globular deposits are found especially on the valve stem downstream from a partition plate in the intake port. Due to the dripping of high-boiling hydrocarbons from the partition plate towards the valve neck or valve stem, globular carbon deposits eventually form there by the sequence of events explained above. These deposits on the valve stem can result in flow deficits due to undesired swirling and turbulent flow around the globular carbon deposits. This may persistently interfere with the formation of stable tumble flow from cycle to cycle."

"A possible solution would be to keep these sources of deposits away, for example, from the intake valve, by completely eliminating exhaust gas recirculation and the introduction of blowby gases into the intake port. However with the combustion behavior of modern reciprocating internal combustion engines, at least external exhaust gas recirculation and the introduction of blowby gases into the intake port are absolutely necessary for reasons of emission control and fuel consumption, so that this approach is not possible. "
__________________________________________________ ______________
Vehicle Make/Model: 2007 Audi RS4
Location: Delaware, USA
Mileage: 54k on 8/7/09
Oil used: Castrol provided by dealer
OCI: 5k
Fuel: 95%-Shell V-Power 93, 5%-Sunoco/Mobil
Avg trip weekday: 15miles. Weekend: 200 miles.

Notes:
Car started feeling sluggish at 25k miles.
Oil had to be topped off about twice per interval.
BG treatment applied at ~32k. No improvement in performance.
3 CEL's for misfires up to 54k.
CEL + EPC at 54k which prompted IM removal and CB discovery.

If anyone has any ideas on how to improve this database let me know and I will update the original post.

Photos:





And here is the link to my thread for more about my experience:

http://www.audizine.com/forum/showth...65#post3967865

I hope everyone find this helpful. Post up!

Vehicle Make/Model. 2008 RS4
Location: California
Mileage in which CB was discovered. 67k
Oil used. Redline Oil/Castrol provided by dealer
Oil Change Interval. 3500-5000K
Fuel Used. 80% Shell 91-20%Sunoco/Mobil
Average Trip daily 120miles (90% freeway/10%city-Est. 35-40k annual)

Notes:
Car started to feel a bit sluggish at times after September (summer). Random EPC lights, but would dissapear after restarting. Misfires on cylinder 1-3-8 started early December '09. Cold starts got very bad/rough idle. Multiple CEL's with DBW & misfires faults.

Vehicle Make/Model. Audi RS4
Location: Pacific Northwest (Oregon, Washington primarily)
Mileage/Date in which CB was discovered. 18k miles, fixed at 24k at my expense, intermittent CEL's would not get them to fix. Down 30+hp on dyno, loss of top end.
Oil used. Castrol primarily, tried Royal Purple, tried Mobil 1
Oil Change Interval. every 3-4k miles
Fuel Used. Shell V-Power 92 octane
How short/long are your trips on average. Work week: 30 miles each way, loads of trip to Seattle and Portland on average 250 miles a shot.


I am somewhat understanding of Audi on this issue, if it wasn't for the strict emissions controls this may be easily solved. However what really irks me is that they know this is an issue, they still make us all suffer through their process to get it fixed. Make us run fuel injector cleaners, make us have constant CEL's. I had CEL's and very rough starts when it got cold for a few months, tried to get the dealers to take a look at it, but they would just say they can't fix unless I have a long term CEL. I finally got tired of the rough starts, took it to an external shop to pull the intake manifold off and get pictures. Paid them for the service, took pictures of all the muck in there, and took it to Audi. The dealer response was "sorry, even though we see it there, its not the worst we have seen, and because your CEL's are intermittent, we won't do anything for you. I couldn't believe this after having owned 3 Audi's from this dealer, and taking my mom in to get an Audi, and steering a good friend to a new TT over a Solstice. They couldn't see fit to save me $700 and do the job for me under warranty? Total bull. After that, I am ready and willing to lend my experience to any lawsuit.

Pics of mine:

Hey guys, I'm going to merge this thread with the thread (Carbon Build-up Megathread)that has been stickied on the FSI Carbon Build-up in the Drivetrain Forum.

I vote for this to be a sticky too, clearly an important issue plaguing the FSI platform!

This thread needs to become very sticky, kind of like the CB these owners are having. I know it sounds cheesy Otherwise this thread will get lost

Guys, this thread IS sticky. Now I just wish it were possible to get it in every FSI model forum. But I'll settle with this.

Edit: Anthony agreed! There is a locked sticky post in each subforum with FSI engine that I'll try to keep synced with this main thread.

is there any consensus on what type of driving is more likely to cause (or delay) this build-up?

Start/Stop city driving, constant RPM highway driving, being a pussy with the "Go" pedal ....etc. etc.

Or does the type of driving have no impact whatsoever?

It might be possible for a lab to do chemical analysis testing on the residue. That might be the most direct way to the answer. I work for a large petroleum company that, if they ever had an issue like this in process piping, would not hesitate to find the chemical makeup of the residue in question before even considering a solution.

I don't know who would do it or how much it might cost though...

edit: maybe these guys http://www.semlab.com/

Edit2: never mind i guess i should read the thread...

I would estimate that the only correlation between driving style and the buildup is that it is clearly caused by the combustion process in these motors. Therefore it could be said that the more you 'combust', the more you will have built up. As gas consumption (combustion) is not directly connected with mileage, you may not find a direct correlation between amount of buildup and mileage.

I smell class action lawsuit

Thanks for your post BEM3, I added your separate thread to the index as well in case there is some good conversation striked up there.

Another one to report.

Vehicle Make/Model: 2008 A4 3.2 Quattro
Location: NY
Mileage: 21,000 mikes
Oil used: Castrol Syntec: 5w-40
Oil Change Interval: 5000
Fuel Used: Mobil or Citgo 93 octane
How short/long are your trips on average: 72 mile commute to work each way, 10k miles on car in about 4 months.

Brought the car into the dealer on Friday for a CEL. CEL had been coming on and off for a few weeks, it would stay on a day or two then go away...then back on a few days later. Every time I made an appointment for service, the light would go off and Audi told me the code was cleared if there was no active CEL.
This time the CEL stayed on about a week and a half. My invoice stated I had a cylinder 1 misfire which happened on 1 occasion. Dealer stated they could do a BG cleaning service for $170 which wasn't covered under warranty. I told him about the CEL's coming on and off, dealer told me it was common and most likely cause was the carbon build up on the valves. Dealer reset the computer this time around, I'll report back if I get another CEL.

Sorry if this is already posted. Looks like Audi has a specific tool to adress carbon on the intake. just a sand blaster type tool but they list it for carbon

http://buy.equipmentsolutions.com/eq...ail.aspx?Type=

I had seen in a post that Audi doesn't even use this any more to clean carbon. Though I have no idea what they're using instead if they have stopped using walnut shell blasting.