BMW’s and Audi’s Direct Injected Engines: The Issue of Carbon Buildup

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BMW EngineBMW and Audi owners should beware of a specific engine issue.

Over the last several years, the auto industry has made the transition from port fuel delivery to direct injected engines, but that has come with it’s own issues, particularly with carbon build up.  Direct injection is when a controlled amount of fuel is precisely sprayed into the combustion chamber of the engine, which increases the power density and the overall efficiency of the engine.  Even tailpipe emissions are usually cleaner with direct injection.  For the most part, the benefits outweigh the negatives, but carbon buildup has been one of the negatives, specifically with regard to BMW’s and Audi’s.

So, what is the source of the problem?  In most cases, the issue stems from the backside of the intake valves not getting sprayed with enough fuel.  The spray of fuel is what keeps the ports clean; and, without it, that’s when the buildup starts.  So, again, why is this happening?  Believe it or not, this it’s actually a matter of software calibration.  As we stated earlier, the fuel must be precisely sprayed and if the software isn’t properly set, an area (most often the backside) will not get the proper lubrication and the buildup starts to occur.

Indeed, an update to the software can go a long way.  It’s the key to keeping everything burning cleanly and efficiently.  If the build up gets too bad, the only true course of action is to eat the cost of replacing the cylinder head; but, with proper maintenance, that can easily be avoided.  In fact, a variety of carbon dissolving products can be administered to break down the carbon.  Then, some good old fashioned scrubbing will get rid of any buildup cause from direct injected engines.

While many vehicles don’t have this issue at all, BMW’s, Audi’s and VW’s are notorious for having this problem, and getting your vehicle into the shop regularly for calibration and cleaning will save thousands of dollars over the long run.  Hopefully, this issue will be fixed as the market for direct injection continues to grow; but, in the meantime, the issue appears to be isolated to particular makes of cars.  Many experts, including some of own employees, still drive vehicles with direct injection because of all the benefits, and we don’t see it as a reason not to buy from BMW or Audi.

The technology has already improved so much over the past decade, and we have to believe it will continue to improve over the coming years.  But, there’s no way to predict the future.  And, here at Alex’s Autohaus, we’d be happy to help.  Give us a call and set up a time for us to take a look at your intake valves to make sure your vehicle is in good shape.  We look forward to hearing from you.