Tuning question for 730 ECM

Dave Zug dzug at delanet.com
Sun Oct 15 05:49:00 GMT 2000


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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