Tuning question for 730 ECM

[Dave Zug]

78 MPH is it?

If you change the parameter, the computer might be defeating your attempt
since some of the RPM readings (therefore perhaps others as well?) will
change themselves *internally* back to 4800 when the RPM is at 4800 or
above. I dont know if speed acts this way in certain cases - I only know
this from being in the room when someone else was pouring over the code for
another reason.

Watch out with some of those software packages - the position and scaling of
a byte can be wrong... CROSS REFERENCE THE CHANGED LOCATION WITH THE HAC's!
doing this can save you some headaches.

----- Original Message -----
From: <timsiford at hushmail.com>
To: <gmecm at diy-efi.org>
Sent: Friday, October 13, 2000 1:31 PM
Subject: Re: Tuning question for 730 ECM


> Blade,
>
> That is the Mandatory Torque converter lockup point. No matter what ...
> the ECM commands TC lockup at that MPH. If you plot your Vehicle Speed
you'll
> notice that the speed still increases even though your RPMs drop.
>
> The newest TC calibration file has a setting in the ECM Constants section
> called "TCC Unlock Prevention Speed Threshhold". That should be the mph
> that you see your RPMs dropping. Only problem is ... even if you bump up
> this setting it doesn't seem to work  I verified that TC is using the
correct
> BIN addresses. They are 100% correct ... but, I think that I am still
seeing
> lock. Modify this parameter to a higher mph ... like 115mph. Burn a new
> chip and then try again. Let me know if it works for you.
>
> Tim
>
>
> At Fri, 13 Oct 2000 11:39:41 -0700, "Edmond" <euro at lvcm.com> wrote:
>
> >
> >
> >Hey guys. In my first attempt to modify a bin file with tunercat, I'm
> >=
> >trying to eliminate the flat spot I see at close to 4000 RPM on the
> >=
> >tach. What happens is when I get close to 4000 RPM in third gear at
> >WOT =
> >the RPMs drop a few hundred RPM then they start creeping back up. Could
> >=
> >it be going lean or not have enough spark ? My Diacom doesnt show =
> >ANYTHING unusual at that spot except of course the RPM drop and a slight
> >=
> >leaning out like a drop of about 50 mv... What do you guys think I =
> >should play with in the bin ? Thanx =20
> >------------------
> >92 Z28 L98 350
> >---------------
> >Ported and polished heads, ported stock TPI base, ported plenum, Comp
> >=
> >Cams XR270HR-10 cam (lift .495/.502 duration 218/224 lobe separation
> >=
> >110), Edelbrock TES headers, LT4 valve springs, Crane AFPR, Flowmaster
> >=
> >catback with LT1 style tips, MSD coil & wires...=20
> >
> >
> >

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