E46Fanatics - View Single Post - Louder than normal engine upon starting
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Old 01-31-2013, 02:23 PM   #4
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Join Date: Apr 2007
Location: Virginia
Posts: 129
My Ride: 2001 M3 Coupe
Agreed. I think in the colder weather, the ECM richens the mixture a bit more and holds the RPMs up a touch higher too. I've always notice my exhaust has a slightly deeper, "richer" and raspier quality after first started when cold -- seems a bit punchier too until it, presumably, reverts back to a slightly leaner, more economical and cleaner mixture. At least that's my theory.
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