WOT open loop/closed loop

[Ron Schroeder]

Hi Christian,

At 10:17 AM 9/24/01 -0400, you wrote:
>
>Ron, 
>My logic in WOT (power enrichment) mode being open loop is so the
>substitute PCM values (12.5:1 -13.1:1 AFR ) are used instead of the O2
>sensors (14.7:1 switching.) That's just how I justified it to myself. 

So with a WB O2 sensor, you could go closed loop.

>
>The pcm still keeps the closed loop flag, but sets the "learn disabled"
>flag, meaning the current events are not changing long term fuel trimming.
>I believe the closed loop flag is still enabled, so the enrichment prior to
>going WOT is retained when at WOT. (Better to be slightly rich before WOT
>basically, to avoid further enrichment during WOT)

I was going to ask about the BLMs in WOT.  So maybe the ECM looks at the O2
only to be a fail safe to prevent running leaner than 14.7:1.

So since part throttle uses BLMs (and the integrator), tuning in that part
of the maps will do very little unless the BLM values are WAY out but
tuning the WOT part of the maps could bring out lots of improvement.  Or am
I off base?

Does the GM ECM do any "learning" at WOT or interpolation from near WOT BLM
cells?


Thanks

Ron Schroeder
WD8CDH
E. E. S.
wd8cdh at bnl.gov
rjs at bnl.gov
ron at 112motors.com
631 344-4561 Day
631 286-5677 Nite
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