2002 LB7 Erratic Shifting & Defuel

[xploitdiesel]

I originally posted this in the wrong section. Hopefully I'll get more help here.

Ive been chasing my tail on this and I cant figure it out. 2002 LB7 running 15186006 OS. The truck defuels hard on every dsp tune except for the base tune. I even tried making all the tunes match the base tune, but tunes 2-5 still defuel like crazy! Does anyone have a good clean 15186006 I could try? Or maybe there's a known solution for this. Seems like a software issue.... has anyone ran into this?

Also, after a few full flashes I got an error saying "Bootloader Failed" The truck still runs & drives... So I tried to read the tune out to see what the ECM did, and I knew it wouldn't read it because it had a DSP5 tune on it...but guess what, it read the whole DSP5 tune right out...no errors or anything. I checked all tables and they were complete and accurate... Like I said though, the truck runs fine on the base tune...it's just the other tunes...even if they are all set to the same values as the base tune...they are all different...

[GMC-2002-Dmax]

They are probably in Metric and Not Imperial.........NM is not the same a Lb/Ft

[killerbee]

Very much the same description noted in this thread. I don't know that this has ever been solved.

http://forum.efilive.com/showthread....-01&highlight=

[DirtyMax03]

I just started working on DSP5 tuning on an 05 LLY and have the exact same problem. As others have said, the tables that control fueling and defueling are the same between all of the tunes at low throttle percentage which is where the heavy defuel is most noticeable. The ONLY tune that doesn't defuel like crazy is the BASE tune which is mostly stock, but like I said the DSP5 tunes are also 'stock' at low throttle positions.

I am going to do some logging tonight. This is my first DSP5 LLY and I did not run into this on my 03 LB7. I know that I could fix it by adjusting the TBIQ table but I hate messing with things when I don't understand what the root cause of the issue was to start with. It makes absolutely no sense to me why the DSP5 tunes would have this issue and the Base tune would not based on the tables.
Did anyone figure out the root cause of this? If not, I guess I will start on a work-around tonight.

[DirtyMax03]

I figured out the issue, so hopefully this will help others in the future. I won't go through the long list of things that I tried, but I found the root cause to be the fact that when I had converted from the stock tune to the DSP5 tune, it had switched the units of the "BASE TORQUE" table in ALL 4 DSP tunes to "Nm" instead of "FT*Lbs". When I then copy and pasted the values that I wanted for the base torque table from a modified single tune those values were in "FT*Lbs" but the DSP tables that I was pasting into were set to "Nm".
This was responsible for a heavy defuel in all 4 DSP tunes. The "BASE Torque" tables in the base tune were still in the correct "Ft*Lbs" units which was why it shifted fine in the Base Tune. The units were Imperial on all other tables EXCEPT base torque which was set to Nm after converting to DSP5.
Hope this helps someone in the future.

[killerbee]

Very nice job. Looks like Tony was on course. I did not have the patience to find the bug. Ross, can that be addressed now?

I figured out the issue, so hopefully this will help others in the future. I won't go through the long list of things that I tried, but I found the root cause to be the fact that when I had converted from the stock tune to the DSP5 tune, it had switched the units of the "BASE TORQUE" table in ALL 4 DSP tunes to "Nm" instead of "FT*Lbs". When I then copy and pasted the values that I wanted for the base torque table from a modified single tune those values were in "FT*Lbs" but the DSP tables that I was pasting into were set to "Nm".
This was responsible for a heavy defuel in all 4 DSP tunes. The "BASE Torque" tables in the base tune were still in the correct "Ft*Lbs" units which was why it shifted fine in the Base Tune. The units were Imperial on all other tables EXCEPT base torque which was set to Nm after converting to DSP5.
Hope this helps someone in the future.

[DirtyMax03]

Killerbee,

How have you gotten around this for your DSP5 tuning then?

I found the units issue at the point where I had given up and was going to start modifying the base torque and TLIQ tables to 'band-aid' the problem which I knew was going to take forever to get dialed in. I noticed the max allowable value for the Base Torque table was 1024 and I was expecting to see 756. I then looked at the units and saw 'Nm' and was glad that I found the problem, but pissed that it took me 2 days of frustration and probably a dozen flashes to the ECM and even a couple to the TCM to figure out that it wasn't a software glitch but rather a tuning (units) issue.

[killerbee]

I feel your pain. I know I have spent over 40 hours looking for a bug when the software was newer. With Ross helping of course. It boggles my mind that this one would exist for over 6-7 years, and nobody tracked it down, or cared enough. It is not a subtle issue.

I can't remember how I compensated for it, being honest. Been awhile.

[DirtyMax03]

I think EFI's DSP documentation says something about converting all units to imperial, so I must have done that when I converted my LB7 tune to DSP5 but must have skipped that step when I did this LLY.

It does seem like this is something that could be corrected by Ross and crew as it only seems to inadvertantly convert the DSP "Base Torque" tables back to Metric (Nm) when upgrading to DSP5.
I assume that other tuners learned this lesson a long time ago because I can't imagine that they trial and errored the Base Torque and TLIQ until they got it to shift decently again. I know some people reduce defuel a little with TLIQ by increasing the mm3 values 5-10% but if you tackled the TLIQ table to fix this unit problem in the Base Torque table I would think that it would take some time to get it all lined out. Since I doubt many people have done this, most must either set everything to Imperial after upgrading to DSP5 and therefore never ran into this problem, or they must have caught this units issue and corrected it.
Because like you said, this issue is not subtle, the truck darn near shuts off during shifts especially at low throttle & rpms.