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?
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