Allison shifting?

[Chuck L.]

01 3/4T. A mild tune, likely less than 75/80HP. All stock, otherwise.
Truck will accelerate VERY well, from a stop, upshift to 2nd, stay in 2nd, at the governor stop, [3300+/-], for several seconds, then shift VERY hard, and continue to "git r done".
NE ideas as to what the cause/fix, [if any] is??

[lakingslayer]

Have you given the trans time to learn the new power? Since it's an '01 the trans doesn't have a fast learn so it may take some time.

[Chuck L.]

Have you given the trans time to learn the new power? Since it's an '01 the trans doesn't have a fast learn so it may take some time.


The tune has been there for over a month, and approx 1000 miles.
:thankyou2:

[chevmeister]

it may have nothing to do with efilive.. happened to a buddies truck recently
CAUSE: clogged fuel filter with only 3k on the filter

[never satisfied]

The tune has been there for over a month, and approx 1000 miles.
:thankyou2:

Did it always have issues, or did it just now start acting funny?

[lakingslayer]

The tune has been there for over a month, and approx 1000 miles.
:thankyou2:

I would have hoped it would have learned by now. When was the last time you changed the fuel filter and the trans spin on filter (how many miles)? Have you tried to remove the tune and see if it still happens?

[Trippin]

01 3/4T. A mild tune, likely less than 75/80HP. All stock, otherwise.
Truck will accelerate VERY well, from a stop, upshift to 2nd, stay in 2nd, at the governor stop, [3300+/-], for several seconds, then shift VERY hard, and continue to "git r done".
NE ideas as to what the cause/fix, [if any] is??

Does it exhibit this behavior in both Tow/Haul and Normal?

[Kennedy Diesel]

The new fuel filters are actually catching dirt and loading up quickly. I have a nifty little gauge kit to diagnose filter plugging/restriction.

[Chuck L.]

Thanks for the input[s]. :wave:
1. I will try it in tow/haul.
2. The fuel filter has about 1500 mi, and the trans filter about 3000mi.
3. I had not had this occur, prior to the "tune up".
4. Truck has 70K on it, but the trans was one of the "leakers", and was replaced at 26K.

We are going to take the tune out, and I'll report back.

:thankyou2: , again....

[dfe1]

http://efiforum.iqd.co.nz/attachment.php?attachmentid=484&stc=1&d=1140934668

Chuck L needs an avatar, here it is

[lakingslayer]

I wonder if he ever got this resolved?

[Chuck L.]

I wonder if he ever got this resolved?
Dfe1 and I are going to do some testing next week. We will try to duplicate the problem, and then try Tow/haul, then reflash to stock tune, and see what happens....

:thankyou2: for the help....

[Kennedy Diesel]

One of the best things that you can do is to get away from the 2001 OS and run the 2002 ECM OS as there are just some odd things with the 2001 programming.

[dfe1]

Attached are two data logs of Chuck L's Duramax, one with a stock tune, the other with a modified +/-100 hp tune. We never experienced the shifting problem, but as you can see, the rpm graph in modified form doesn't look right. Any ideas? We also had a G-Timer runing and it consistently showed a 2 second (two, not two tenths) improvement in 0-50 times.

[GMC-2002-Dmax]

Looks like you were at 3250 and could have been bouncing off the rev limiter, also at WOT 100% in Non-TH the Converter will be slipping and not locked.

The drops in the fueling mm3 coincide with the rpm changes, those are TQ Limited injection Quantity commanded defuel on the shifts.

Dave, is that second tune the one I sent over to you in December ??? Or is it one you wrote.

TONY

BTW, if you have a commercial version you can reflash your 2001 ECM O.S. to a 2002 O.S.

I just did one and it works fine on ECM Hardware #9355100 -Original O.S. #15188873 Calibration #15063375

to a 2002 ECM O.S. #15186006 Calibration #15166858.

[dfe1]

Looks like you were at 3250 and could have been bouncing off the rev limiter, also at WOT 100% in Non-TH the Converter will be slipping and not locked.

The drops in the fueling mm3 coincide with the rpm changes, those are TQ Limited injection Quantity commanded defuel on the shifts.

Dave, is that second tune the one I sent over to you in December ??? Or is it one you wrote.

TONY

BTW, if you have a commercial version you can reflash your 2001 ECM O.S. to a 2002 O.S.

I just did one and it works fine on ECM Hardware #9355100 -Original O.S. #15188873 Calibration #15063375

to a 2002 ECM O.S. #15186006 Calibration #15166858.
Tony-
It is the second tune you sent back in December. Seemed to work fine for a few months, then recently started acting up. I pulled back on the fuel about 10% and that seems to have fixed it, but until we have a few miles on it, I don't want to say for sure. Power appears to be down slightly, but that's to be expected with less fuel. I don't think we're tapping the rev limiter-- I moved it to 3650, but even if you hold the trans in gear, the engine won't go over 3400-- I think that's the result of a fueling calibration. What are the advantages of the 2002 O.S.? I do have the commercial version.

[GMC-2002-Dmax]

Dave,

The 2001 O.S. is unique and a one year only O.S.

It has been known to do very strange things with regards to handheld Flash Tuners corrupting the data.

EFI-LIVE seems to be the only software working without issue, but there have been issues with the 2001's getting weird for no reason.

We found out years ago that the 2002 ECM's always worked very well in 2001 trucks, Nobody until now had a way to update the 2001 ECM's to 2002 programming, calibrations.

I just did a BENCH FLASH Full O.S. update on a 2001 ECM to a 2002 O.S/Calibration and tested it in my truck.

All worked well and it seems that a lot of 2001 specific problems can be traced to the ECM and programming.

Tony

[dfe1]

Tony-
Right now the truck seems to be running fine, but this stuff is pretty spooky in terms of the way the trans reacts to changes made to the engine calibrations. As I mentioned, the tune that you sent worked great for a couple of months, then the trans started acting like it was infested with gremlins. The same thing may happen with this tune, we'll have to wait and see. I'll try upgrading to a 2002 OS in a few weeks and see what the effects are. I'm assuming the upgrade works just like it does with the gas engines-- you just do a full reflash, then load in your calibration file and save everything. Thanks for all your help and input.
Dave