MemCals Needing a Good Home...

[ae2598 at wayne.edu]

Has anyone been able to come up with a pinout and/or internal connection
diagram for the netres?  And while we're at it, could someone explain HOW
a resistor network provides a malfunctioning ECM with the ability to "limp
home"?  Maybe I'm just misunderstanding the function of limp home mode,
does it require that the hardware is OK, but the data in the PROM is
corrupt?

 On Wed, 8 Nov 2000, Walter Sherwin wrote:

> The "trick" is to program the EPROM with a suitable CAL that would have been
> destined for such a MEMCAL/ECM combo,  and then find the pin coming from the
> NETRES which defines the hardware moding, and alter it to reflect the
> contents/intents of the new EPROM CAL file via ratiometric voltage jumpers.
> Every MEMCAL and application differs, but there are a few threads in the
> older archives which describe how this moding thing works.
> 
> In this fashion, for example, a 27c256 equipped MEMCAL can be salvaged for
> use as something other that the intended OE application.  I would, however,
> NOT rely upon the resultant limp home fuel mode!
> 
> For the $30-45 CDN that these MEMCALS cost, it might be best to find one
> that's already been V8'ed (or moded) from your local GM dealer, and then
> dump your CAL into same.
> 
> 
> Walt.
> 
> 
> ----- Original Message -----
> From: "steve ravet" <sravet at arm.com>
> To: <gmecm at diy-efi.org>
> Sent: Wednesday, November 08, 2000 3:07 PM
> Subject: Re: MemCals Needing a Good Home...
> 
> 
> > Won't work -- EPROM specifies the number of cylinders as does the netres
> > via a resistor divider.  If the two don't match you get limp home mode.
> > Ludis posted once what voltage levels are used to indicate the number of
> > cylinders.
> >
> > --steve
> >
> > WEG1192 at aol.com wrote:
> > >
> > > I have an idea for your MEMCALS.  Is it possible to ground pin 56 of
> > > the
> > > MEMCAL, and reprogram the EPROM as a V8 TPI or whatever, and use this
> > > as your
> > > V8 MEMCAL? A short wire soldered to a ground leg of the ESC module and
> > > pin 56
> > > should do it after snipping the netres pin. If the engine is not a
> > > small
> > > block Chevy, then my understanding is you can't use the knock sensor
> > > anyway.
> > > Of course, you lose limp home this way too, but will it work? Anyone
> > > "chip"
> > > in here.
> > >
> > > JW
> >
> > --
> > Steve Ravet
> > steve.ravet at arm.com
> > ARM,Inc.
> > www.arm.com
> > --------------------------------------------------------------------------
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