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

[Keith D. Miller]

> -----Original Message-----
> From: owner-gmecm at diy-efi.org 
> [mailto:owner-gmecm at diy-efi.org]On Behalf
> Of ae2598 at wayne.edu
> Sent: Wednesday, May 09, 2001 10:17 PM
> To: gmecm at diy-efi.org
> Subject: Very basic newbie question about A.I.R. pumps
> 
> 
> 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?
>

The extra air is added to exhaust ports only during
warm-up, after that it's directed to the cat. Beyond the
O2 sensor, so it has no effect on the O2 or mixture.
 
Keith
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