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Old 11-19-2012, 03:42 PM   #5
mkodama
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The reason is to clear fuel from the cylinders. It has the added benefit of making intimidating engine noises to scare potential competitors (either at the valet or the race track). Needless on cars with EFI since at most you'll have one combustion cycle worth of fuel in the cylinder which will evaporate within seconds in a still hot engine.

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Originally Posted by flashtwosix View Post
Yes...ms43 and higher does this since there is no return fuel line from the fuel rail.

sent from my dahc-6900 using Bimmer App
No, and it has nothing to do with no return line from the fuel rail. Shanneba gave a good explanation, and the key words to acknowledge are emission optimized. Letting gasoline evaporate is wasteful and is not good for the environment.
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