[Gmecm] BLM cell confusion

Fri Nov 11 04:07:21 UTC 2005

Yes, exactly.  Entering cell 2 (by reving in neutral)
swings the INT to 137-ish, but the cell 2 BLM doesn't
change off 122.  I don't know if learn enable has some
kind of qualifier that I'm not meeting in neutral
(MPH? MAP? BPW?) or what, but cell 2 appears to be the
only one that doesn't move.

An interesting side note is that my BLM data varies
widely depending on the driving that I do.  But - I
guess that's to be expected if the $a1 truly does use
only 2 BLM cells (idle and off idle).  I don't know
that it does.  I can say that BLM cell 2 does appear
to be calculated from the cell 0 (idle) and cell 1
(seems to be a changing TPS).  I never see cell 2
actually change, it only changes when you're in other
cells... "behind closed doors" so to speak.

Now, from what I have seen in my data logs, it appears
as though the INT has to be off from 128 by 4 (from
the "C/L INTEGRATOR WINDOW VALUE") before the BLM will
start to compensate, in which case, my idle cell INT
of 124 would be acceptable for no BLM compensation.

Ryan

--- Steve Ravet <Steve.Ravet at arm.com> wrote:

> In general, "closed loop" allows the INT to vary to
> maintain stoich.
> "learn enable" allows INT changes to be accumulated
> in BLM.  Are you
> comparing driving around, where the BLMs move, to
> revving in neutral,
> where they don't?  Or what is the different
> condition that causes them
> to not move?  Either way, I don't know the answer to
> that one, why
> "learn enable" is enabled in one case, and disabled
> in another.  Anyone
> else got an idea?
> 
> --steve
> 
> > -----Original Message-----
> > From: gmecm-bounces at diy-efi.org 
> > [mailto:gmecm-bounces at diy-efi.org] On Behalf Of
> Ryan Hess
> > Sent: Thursday, November 10, 2005 2:17 PM
> > To: gmecm at diy-efi.org
> > Subject: RE: [Gmecm] BLM cell confusion
> > 
> > Thanks Steve.
> > 
> > My next question is what qualifiers there are that
> > enable the BLMs to move?  I can drive around and
> the
> > BLMs move just fine in response to the INT
> changing -
> > however - If I reset the PCM, start it up and
> bring it
> > up to temp, and enter cell 2 (high RPM, about 1500
> it
> > seems) you can see the INT rise quickly to 138,
> but
> > the BLM stays stuck on it's default 122.  Cell 0
> > (closed throttle/idle) also stays on it's default
> of
> > 128, althoug the INT is 124, so that probably
> isn't as
> > big of a deal..
> > 
> > Ryan
> > 
> > 
> > --- Steve Ravet <Steve.Ravet at arm.com> wrote:
> > 
> > >  
> > > 
> > > > -----Original Message-----
> > > > From: gmecm-bounces at diy-efi.org 
> > > > [mailto:gmecm-bounces at diy-efi.org] On Behalf
> Of
> > > Ryan Hess
> > > > Sent: Sunday, October 30, 2005 12:37 PM
> > > > To: gmecm at diy-efi.org
> > > > Subject: [Gmecm] BLM cell confusion
> > > > 
> > > > Hi everyone,
> > > > 
> > > > I'm working with the $A1 code, and have been
> > > slowly
> > > > conquering a steep learning curve.  I'm still
> > > greatly
> > > > confused about the BLM cells.  How they work,
> and
> > > the
> > > > differences between cell 0, 1 and 2...  For
> > > instance,
> > > > I've gathered cell 0 appears to be closed
> throttle
> > > > idle conditions.  The others I don't know. 
> > > Secondly,
> > > > how do the BLM cells increment?  They follow
> the
> > > INT,
> > > > but how?  'preciate it,
> > > > 
> > > > 
> > > 
> > > The INT is part of the feedback loop and so
> > > constantly moves up and down
> > > as the ECM maintains stoich.  There is no
> "history"
> > > with INT, it just
> > > changes to whatever value is required.  The BLM
> > > provides the history.
> > > If the INT is consistently high or low for a
> period
> > > of time then the BLM
> > > will start to move in that direction.  Both INT
> and
> > > BLM are part of the
> > > fueling equation, so as BLM starts to move INT
> will
> > > tend back to
> > > neutral, or 128.
> > > 
> > > So say you had a plugged cat.  The reduced
> airflow
> > > will cause the INT to
> > > drop and cut back on fuel.  Since the INT is
> > > consistently below 128 then
> > > BLM starts to drop also.  As the BLM drops and
> cuts
> > > out fuel, it allows
> > > INT to rise back around neutral.  So right after
> it
> > > plugs you'll see
> > > normal BLMs but low INTs.  As time goes by
> (maybe a
> > > few minutes?) you'll
> > > see BLM drop and INT rise back to neutral.  Then
> the
> > > opposite happens
> > > when the cat is fixed, and eventually both of
> them
> > > rise back to near
> > > neutral.
> > > 
> > > Generally BLM is a table indexed by MAP and RPM,
> > > like the VE table.  I
> > > think there are exceptions where there is one
> BLM
> > > number for idle and
> > > another for everything else.  Not sure about
> your
> > > specific situation.
> > > 
> > > --steve
> > > 
> > > _______________________________________________
> > > Gmecm mailing list
> > > Gmecm at diy-efi.org
> > > http://lists.diy-efi.org/mailman/listinfo/gmecm
> > > 
> > 
> > 
> > 
> > 		
> > __________________________________ 
> > Start your day with Yahoo! - Make it your home
> page! 
> > http://www.yahoo.com/r/hs
> > _______________________________________________
> > Gmecm mailing list
> > Gmecm at diy-efi.org
> > http://lists.diy-efi.org/mailman/listinfo/gmecm
> > 
> _______________________________________________
> Gmecm mailing list
> Gmecm at diy-efi.org
> http://lists.diy-efi.org/mailman/listinfo/gmecm
> 

__________________________________ 
Yahoo! FareChase: Search multiple travel sites in one click.
http://farechase.yahoo.com