Re: EPROM Programming

[Scot Sealander <Sealand@clarityconnect.com>]

David Posea wrote:
 
> Ok, it's question time here. Does the GM adaptive control function at all
> times, or only in closed-loop trying to maintain 14.7:1 A/F?

There are really two parts to this question.  What does it do in 
closed loop and open loop.  The feedback part that actually changes 
the BLM is only active when the AFR is at stoich. This is because the 
feedback device (the O2 sensor) only functions properly at that AFR.
This mode is closed loop.

When at WOT, the ECM goes open loop and is no longer at stoich AFR.  
It is in open loop, even if the scan tool still says it is in closed 
loop.  Once on, GM usually never shuts off the closed loop flag unless
the O2 sensor dies.

Now does the ECM use what it has learned from O2 feedback at WOT, or
open loop mode?  Yes. They all add fuel if learning has told it to 
add fuel.  Most, but not all, will not let the code remove fuel if 
in PE, and it has learned to remove fuel.

You can change BLM boundaries so that the ECM will not learn in
the BLM cell used at WOT.  So then, when in WOT, the fuel will not
be altered from the normally calculated value.

Good advice is to know your cal...

Scot Sealander
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