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Old 06-05-2012, 11:57 PM   #36
PERRIN_Jeff
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Boxers in general do not make any tapping noises. The tapping from your FA20 engine is 100% from the Direct injection injectors firing. As some have pointed out, the fuel pressure is very high and when they fire the injector, it uses 80V-ish to pull the injector open. This creates the noise you hear.

What I have found is that sometimes at idle, the DI injectors are not firing at all and its much quieter. Then sometimes is firing 100% of the time at idle. Probably a way that Subaru cleans out the engine, or tests out the cats, or a lean burn situation. Who knows for sure. This creates that noise that isn't always there. That isn't good for customers as its going to create a lot of calls to the dealer over nothing.
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