E46Fanatics - View Single Post - CEL light on....SAP bad and other engine performance problems
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Old 01-26-2013, 07:34 PM   #30
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Join Date: Jan 2012
Location: Nashville, Tennessee
Posts: 2,107
My Ride: 2002 330ci
will try to log more data tonight with cold starting.

the extra air injected at cold start is to reduce emissions by adding the air to the unburned fuel. i know its not causing the bad mileage but over time....without it and the car being designed to run it. that unburned fuel that is not getting oxidized is going into my cats and could be fouling out the o2 sensors. i dont know if that worry should even be a concern. the unburned fuel might pass right through without gumming up or clogging. i dont have enough experience with it to know how much time or fuel will have an effect
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