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View Full Version : DSP5 upgrade-abnormal operation, 01



killerbee
April 25th, 2011, 08:22 AM
I assume this 2001 will have the 505 ECM, but I didn't look.

I have verified, in several trial experiments, that the DSP5 upgrade produces strange results when not using the base tune. I will just copy the request for assistance I did a month ago, and see if anyone here has noted similar findings. I am no longer asking the manufacturer for assistance, it was declined. Maybe Tony has some insight.


"I found an issue with LB7 fueling, which I originally suspected was shift defuel-related. I have only recently been involved in LB7 tuning, or else I would have brought this to you sooner. I have only a couple of days with this testbed to work it out, so i hope you can give me a piece of your day, as I think it will help others as well.

After making some anomolous observations where some dsp tunes behaved poorly (during shifts) without predictability, I decided to do an experiment. I structured a dsp5 tune with 5 identical tunes. In theory then, all tunes should behave identically. I found that they don't. I zipped up the tune and 2 logs to demonstrate.

When I run one of the dsp settings (using the V2 to switch tunes), I get different defueling results with the shifts. It is quite clear on the logs at around 30% TP, light fueling, and the shift feel quality is even more obvious. You will see it when the torque reduction (shift) commands defuel. The dsp0 (main tune) log demonstrates the defueling I am trying to accomplish with all tunes. The dsp3 log shows the excessive torque-directed defuel , a significant % increase over the dsp0 log. Each dsp position has the same problem.

Then I started looking at the tunes to see if some other issue might be happening. I looked closer and determined that the fuel number inside the shifts actually was the same between the tunes. So I looked closer at regular TBIQ (non-shift) fueling. The logs all reflect more fueling than the tune suggests in the AX102 TBIQ tables. In fact, none of the logs show fuel mm3 that is predicted well by the TBIQ tables, with the dsp tunes being the worst disparity. So by my estimation, the torque tables are ok I think. What is different between the tunes is the fueling state before the shift starts, it is higher in the dsp tunes. There is no explanation for that if all tunes (including TBIQ) are theoretically identical. So perhaps this is where the difference is?

I hope you can find some kind of explanation in the software. This is a very important issue for us, as it makes LB7 dsp tuning extremely difficult to do at all with any kind of consistent refinement, a moving target. All flashes are full flashes, fyi. Thank you for your time.


Regards
...."


I did use the V2 as the dsp5 switch during these findings. Thanks everyone.

GMC-2002-Dmax
April 25th, 2011, 12:27 PM
I would suggest you do not waste your time with any 2001 OS and simply use the 15186006 2002 OS. It works the best on the 2001/2002 trucks, it has no quirks, it will work with a auto climate or manual HVAC truck, I have the 15186006 OS for a ZF6 speed/manual T-Case as well as a Allison/Manual T-case.

I know you like to find answers to problems so I am going to try and save you from wasting your time by strongly advising you to just uses the 15186006 OS and upgrade any of your 2001 trucks to that OS. The only thing they lose is the 850 rpm standby idle.

Good Luck

Oh one more thing, shift quality on a LB7 or LLY is derived from a combination of many tables, if you change the wrong one you can chase your tail looking for the answer. It took me 6 months to figure out my mistake early on, once I corrected my mistake the shifting became very easy to fix.

Hopefully you did not make the same mistake I did in 2005 when I was Beta testing, if you did I hope you figure it out.

killerbee
April 25th, 2011, 03:21 PM
Thank you for the suggestions, Tony.

It was dsp5 upgraded from the original, 15094441, fwiw.