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Re: Editing proms (editorial)

Kevin R wrote:
> 
> Now for my continued learning, are you (Ludis) saying that the ECM(in my
> case a 747) will adjust the constant somehow thus making the numbers more
> accurate?
> Example:
> Say I have a 350 with 70lb injectors and the constant is set for this
> injector/CI combo. Then if I bump up the FP to increase the injector output,
> thus throwing off the VE and AFR numbers in the ECM. Will it (the ECM)then
> see that the command AFR is off and make an adjustment bringing everything
> back to close to real numbers? I was under the assumption (never assume I
> know) that it would just move the BLM and call it a day leaving the WOT, PE
> etc AFR numbers off. Since in this case the constant (if not adjusted) would
> be set for 70lb while the injectors would be actually putting out say
> 85-90lb making the AFR richer than the bin called for.

When the ECM goes closed loop, it'll see that the VE numbers are wrong. 
It'll (try to) adjust the BLMs to bring the engine back to stoich.  In
other words, while the requested AFR is 14.7:1, the ECM will adjust the
BLMs such that the engine really is running at 14.7:1.

If you then go to PE mode (ie, request an AFR richer than 14.7:1), the
ECM will do some math and end up running the engine very close to the
requested AFR.  (There are conditions under which it will ignore the
learned BLMs.  Or the BLMs may poorly map the conditions experienced
during PE.  Either will throw the actual AFR off from what the ECM
thinks it is generating.)

I don't quite understand where your confusion is.  The ECM never
"changes" the injector constant or the numbers is uses for AFR.

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/


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