Exhaust Air Pump

["Louis Goldsman" <goldsman@xxxxxxxxxxxxx>]

In a prior post Craig Robson responded to another post that mentioned a
"second fan for the engine"  that ran for about 2 minutes after startup.
Craig surmised the item was the exhaust air injector smog control pump.
Craig commented that if the pump ran for only 2 minutes it should be
checked.
As it happens the air injection pump on my car has had a bad bearing for the
last 3 years - when the pump is on it squeals like a hog-tied pig (is that
redundant?).  As a result I always know when the pump is on.  As it is
controlled by an electrically controlled clutch driven by the fan belt, like
an air compressor  clutch, it isn't always on.  As a matter of fact, mine
has never been on for more than two minutes after a cold start.  If the
engine is not completely cold it doesn't come on at all.  It also won't come
on if the car has been sitting for a few days and it is a warm summer
morning.  Only when it is cold outside, I'm guessing in the neighborhood of
65 degrees or colder (well, at least cold by southern California standards),
does the air pump come on at all.  On the first car I owned that had an
exhaust air injection pump, a 66 Pontiac Tempest LeMans, the pump ran
continuously (well, only when the engine was running).
I wouldn't worry about the pump.

Louis
91 ///M5

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End of bmw-digest V9 #188
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