[Gmecm] Adjusting 7730/$8D for larger cam

[Clair Davis]

John,
Question regarding the O2 constants you mentioned...

In the Constants/Scalars section, I've got:
0.60V at 496 (Idle O2 Rich/Lean Threshold Fast)
0.60V at 497 (Idle O2 Rich/Lean Slow Zero Error Upper)
0.56V at 498 (Idle O2 Rich/Lean Slow Zero Error Lower)

Are you saying to knock them all down by 0.04 - to 0.54, 0.54, and 0.52?  I
haven't done that yet, but I can before I burn again.  I bumped the idle
spark advance at 800rpm up to 24.96* from 20.04* in the Closed Throttle vs.
RPM table.  That's the same as the 1200rpm point, not a big bump, and this
engine likes idle advance.

With some luck, I'll get to try this out tomorrow, and see what the BLM's
look like as well.

On a semi-related note, what are some thoughts on saving versions of bins to
help track progress?  I've got very few changes at this point, so I've been
keeping essentially a single file so far.  I can see how I'll need multiple
files in the very near future, and I'd like to keep up with what has been
changed.  I'm thinking date-stamp-type file names, but that can get
ungainly, and the XDF would have to be changed at the same time.  Maybe no
biggie, if I keep the date stamp in a directory name.  There must be some
tidier ways, though.

Thanks again,

Clair

----- Original Message ----- 
From: "JohnsHome" <JohnsHome at wideopenwest.com>
To: <gmecm at diy-efi.org>
Sent: Thursday, February 01, 2007 9:32 PM
Subject: RE: [Gmecm] Adjusting 7730/$8D for larger cam


> I would suggest upping your idle timing a bit to see if that helps.
(closed
> throttle table L81FD-8209)
> Removing about 40mV from the o2 constants may help as well.
> They are at L8496 thru L8498 locations. Will get the smell of unburnt fuel
> to get better as well.
> Not knowing what cam you are running, although it sounds like its mid 220
> range from the description I'm not sure what else to suggest. Hopefully
you
> are running a heated o2. If not, get one for sure.
> Idle will probably need to be around 700-800 rpm.
> There is a hard code idle limiter in AUJP if that is what you are running.
> It can be increased by changing BOTH values to be the same at locations
> L426C & L4270.
> these are in the code and will need to be added to your XDF or just done
in
> the hex editor.
> They are single byte, RPM = 6400/255 = 25 rpm increments.
> For 1000 RPM max idle you would use a value of $50
> These have helped me out with my 224/230 roller 350. My idle is at 58Kpa @
> 800 RPM.
> HTH
> John
>