Very basic newbie question about A.I.R. pumps

[Shannen Durphey]

I don't believe the AIR pump is used in closed loop.  I know that years ago when I
was travelling 2 hrs to school, I ruined an engine in an 82 Cavalier because the
diverter valve was faulty.  The ecm continually richened the fuel mixture based on
added air in the exhaust, and the rings were eventually ruined.  The irony is that
I was in GM college at the time. ; )  But to qualify my reply, I haven't spent a
lot of time with AIR pumps since I started working in dealerships 10 years ago. 
Most of the vehicles in Montana weren't equipped with them, as the air is clean
enough out there not to need them.  I do know that I've never replaced an engine
because an air pump had been removed.  AIR pump removal was not uncommon in MT,
since no self respecting farmer will pay money to replace something which he
doesn't need.  Im currently in a state that requires a visual inspection of
emissions systems, but no smog test.  So again, there are situations where the AIR
pumps get disconnected with no apparent ill effects.

FWIW.
Shannen


ae2598 at wayne.edu wrote:
> 
> Having just bought a smog pump equipped EFI vehicle, I began to wonder
> what effect the pump has on the ECM's calibration.
> 
> It would seem to me that the air added to the exhaust stream would cause
> the O2 sensor to read falsely lean.  The ECM would compensate for this
> with a richer-than-normal fuel table, I would think.  The result of
> removing the pump, then, would be a rich-running motor and BLMs probably
> going haywire to boot.  Is this an accurate assumption?
> 
> Are AIR pumps typically omitted on vehicles exported outside the USA?  If
> so, would an export-calibration be a good starting point for a Federal
> motor w/ the pump removed?
> 
> The vehicle in question is a '92 S-10 pickup, 2.8L V-6, 2wd, 5-speed, by
> the way.
> 
> Kevin
> 
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