Preventing and Fixing Carbon Issues for Direct Injection Engines ~ Episode 80

Carbon buildup direct injection

Happy Friday everyone. Today I am back in the Passat with another automotive podcast. I get asked about carbon buildup on direct injection engines all the time. Generally they are asking about the newer VW engines the TSI. That would be engine codes CCTA and CBFA. These direct injection engines are developing issues with carbon on the back of the intake valves. This is not just a VW problem. This is an issue with most direct injection engines.

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Join me today as we chat about:

  • Why these engines have carbon build up
  • Theories from BG products
  • PCV systems
  • Oil service lengths
  • How to prevent carbon buildup
  • The “Italian TuneUp”
  • How to fix carbon buildup
  • VW recommended fuel treatment
  • and more

Trouble viewing? Watch “Preventing and Fixing Carbon Issues for Direct Injection Engines ~ Episode 80” on YouTube.

As always I love to hear your thoughts. Please post them in the comments section below. Again, if you have a question for a show like this, email me Charles(at)humblemechanic(dot)com with Question for Charles in the subject. Also if you have an idea for a show you can email me, or use the contact me form! Don’t forget to follow me at:Carbon buildup on valves

11 replies
  1. Pat ~ The Muscle Car Guy
    Pat ~ The Muscle Car Guy says:

    I like the reference to the Italian tune Up.

    Have you ever seen anyone try a light mist of water in the intake when the engine is good and hot?

    I have used it with a snow blower engine to clean up carbon, and it worked good. Although I don’t know if it would cause issues with various sensors in modern car engines.

    Plus too much water could cause issues as well.

  2. J_Fix
    J_Fix says:

    I wonder if the cylinder head where hemispherical, it might change the air/fuel swirl and be able to mix in with all the available space and air. Of course then one should consider the “problems” of a hemispherical engine with direct injection.

  3. stephan
    stephan says:

    I heard you mention a catch can. I have read quite a bit about them but there seems to be little long term analysis. To me it makes sense but before I spend $300 or so dollars on one I would like to know if they are effective against carbon build up.

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  5. Albert
    Albert says:

    HumbleMechanic: what’s the difference in terms of wear and tear between driving in S mode and driving in D mode on a 2.0 TSI, especially regarding pistons and valve wear. Thanks.

  6. Glenn Fresch
    Glenn Fresch says:

    Have there been any VW engine management software updates to help deal with the carbon build-up problem with direct injection engines?

    Your video was very helpful in understanding the issue. I just got a call from my VW dealer who’s replacing the leaking water pump on my wife’s 2012 VW Tiguan at 54K miles. In removing the intake manifold, the dreaded carbon build up was found. Did I want to pay less now or more later to fix a problem I had not anticipated? I voted for “less now”.

  7. Matt Merrick
    Matt Merrick says:

    Thanks for the video. It was great and very informative. Here is our deal, and would love your input.
    We have a 2012 Tiguan with 100K miles and the check engine light just came on. Took car to VW dealer and he told us about the fuel injection causing carbon build-up. Price to fix was quoted at about $1,250. He said if we did not fix then we would risk failure of the catalytic converter at some point. The repair cost would then at least double if not more. I do not have any ‘symptoms’ with knocking or cold start problems, though I don’t really track mileage which might be deteriorating. So, would appreciate any feedback you can offer about the catalytic converter risk or on the best and cheapest solution to reduce or eliminate the buildup.

  8. Z
    Z says:

    My check engine light just came on in my 13 Tiguan. Took it to the mechanic and was told I have carbon build up that needs to be cleaned off because its causing all 4 cylinders to misfire. Every weekend I drive over 100 miles and I hit 100+ mph for 30 of those miles so Italian tuning will not prevent it either. I also only use chevron supreme gas(no super supreme near me). I’m at 99,400 miles so maybe all that speeding lessened the build up? Just wanted to put on my 2cents


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