[Gmecm] RE: More '730/$8D tuning questions...

[dozierhc at aol.com]

Clair...
 
I guess we now need to start looking at details of your equipment, and how calibration is transferred to the EPROMs.
 
1) What EPROM type are you trying to use (eg: 27C256-25, etc?)  Maybe EPROM is too slow?
2) If using a 1227730/1227727 series of ECMs, are you using a 32K (27256) EPROM, or something else.
3) If #2 is other than 27256 type EPROM, are you placing the code at correct offset in chip memory, as well as absolute addressing for SW?
4) Maybe details on how you create, checksum, verify checksum, and burn a EPROM can shed light on this, as well as the equipment used.
 
Not trying to point out any mistakes here in the above questions, but something is going on that should be easy to fix when thoroughly understood.
 
Hank
 
*****************************************
Message: 1
Date: Sun, 22 Apr 2007 20:50:31 -0500
From: "Clair Davis" <clair.davis at charter.net>
Subject: Re: [Gmecm] More '730/$8D tuning questions...
To: <gmecm at diy-efi.org>
Message-ID: <003101c78549$c7013380$03000004 at davis>
Content-Type: text/plain;   charset="iso-8859-1"

Well, I'm at a loss.  I've tried to copy over the necessary bits of my
previous tune attempts (injector size, displacement, etc) to both AXXC and
AXXD, supposedly known-good 5-speed .bin's, and in every case, they drop in
to limp-home mode almost instantly.  The only code I can retrieve is 12,
ECM, so something is very seriously wrong.  If I'm switching .bin's on the
fly, I can upload my old last attempt, and all gets better.  SES/CEL goes
out, mixture leans out to stoich +/-, and MAP jumps up in to the mid 40's.
I've been through almost all of the various items you can edit through
TunerProRT, and anything obviously strange is evading me at this point.  I
think about all I can do is go through the various tables that appear
related to an auto trans in my .bin and copy in the parts of the 5-speed
.bins I have (AXXC/AXXD/.  I don't know what that will really do for
drivability, but at least it makes it a bit more "right".

Now for the question.  My gut feeling is that I need to seriously adjust my
Accel and Power Enrich functions to make this thing more drivable in the
near term.  I believe this is the case because when the car is in warm-up
mode, throttle response and transition is pretty dang good, but AF is in the
11-12 range.  I think that's fat enough to cover most enrichment sins until
it goes to closed loop.  Where can I find a good description of the
variables in these functions?  I need to be able to change the variables
that make the greatest contribution to the adjustment factor.  So far, the
XDF file for TPRT hasn't really given me what I want, and the book I got
from Customefi's has only discussed the BPW this way.

I'm eventually going to need the same formula info for the spark advance,
but I think PE/AE is the big problem at the moment.

Thanks again,

Clair
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