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Discussion Starter #1
Went to pass some clueless a$$hat in a Prius today, mash the pedal and absolutely nothing for what felt like an eternity. Has anyone figured this out yet on the LMLs??
 

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Ease into the pedal, mashing it seems to make it worse..
 

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Can't confirm anything with the LMLs, but my buddy that has a 6.4 powerstroke has the same issue and found out it is in the programming for the throttle. Some sort of attempt at an economy saving piece. Keep you from wasting fuel with excessive acceleration. Could be the same thing on the Duramax I guess. But again, that is just me tossing an idea out there, no idea that it is fact
 

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H&S problem solved for me
 

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Agree with OP. This is one serious negative on an otherwise decent machine. Annoying at best, dangerous at worst.
 

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I may be wrong, I dont think so though, but when mashing the skinny pedal to the floor all at once the ECU will downshift the tranny, obviously, the lag time comes from waiting for the tranny to secure the downshift, maintain line pressure then...go. It is the worst if you are cruising at the bottom rpm range of one gear, say 5th gear for example, smash the gas, it downshifts past 4th and into 3rd. Tuning does help. easing into the gas at first then let it eat also helps.
 

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Discussion Starter #7
I've driven older Dmax trucks using the same Ally transmission and not experienced anything compared to the lag I get in the LML. I'm not buying this is the nature of the beast.
 

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Just a guess, but I don't believe the dead pedal is all torque management or turbo lag. I think it is designed to reduce soot and DPF loading. You know how deleted rigs always crank out a ton of smoke at the instant the throttle is snapped open, then it clears up a couple seconds later with the throttle on steady. Maybe GM slowed down the throttle response just to get rid of that initial shot of smoke.
 

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Y'all need the ESP mod guys I'm tellin ya!

The pedal knows what im gonna do before I do it! No lag :D
 

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GM has been known in the past to play with throttle positioning and throttle response in efforts to help with fuel economy they have been doing that since the late 1990's and it makes you're vehicle feel gutless, Im not positive this is the problem but sounds like it. if you get in touch with a good tuner they should hopefully be able to alleviate this issue.
 

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Just a guess, but I don't believe the dead pedal is all torque management or turbo lag. I think it is designed to reduce soot and DPF loading. You know how deleted rigs always crank out a ton of smoke at the instant the throttle is snapped open, then it clears up a couple seconds later with the throttle on steady. Maybe GM slowed down the throttle response just to get rid of that initial shot of smoke.
That would definitely make sense. But at the same time I only notice that a good bit when in my +120 tune and the tc is locked. On a stock tune it's a real challenge to get it to smoke under any circumstances. But maybe you dont necessarily see the particles that the dpf collects.




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Just a guess, but I don't believe the dead pedal is all torque management or turbo lag. I think it is designed to reduce soot and DPF loading. You know how deleted rigs always crank out a ton of smoke at the instant the throttle is snapped open, then it clears up a couple seconds later with the throttle on steady. Maybe GM slowed down the throttle response just to get rid of that initial shot of smoke.
I think you may also be onto something with this... Possibly a combo between what I was saying earlier and this theory, perhaps...:cookoo[1]:
 

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Discussion Starter #15
I may be wrong, I dont think so though, but when mashing the skinny pedal to the floor all at once the ECU will downshift the tranny, obviously, the lag time comes from waiting for the tranny to secure the downshift, maintain line pressure then...go. It is the worst if you are cruising at the bottom rpm range of one gear, say 5th gear for example, smash the gas, it downshifts past 4th and into 3rd. Tuning does help. easing into the gas at first then let it eat also helps.
I have a hard time believing a modern auto trans can take this long to secure a downshift. I could downshift a manual trans faster than this dead pedal delay takes... My previous tuned 2500HD with 6.0 and 4L80E would kick down from 4th to 2nd like nobody's business.
 

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^ Maybe so, I noticed it a little on my 06 dmax, although not as bad as the lml, got built trans EFI tuning and it was cured (my trans wasn't build). So, that tells me that there maybe, just maybe, some truth to my theory, of it being a trans safety thing of some sorts along with throttle positioning tuning from the GM. H&S tuning helped a decent amount on the LML. Other than that IDK
 

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the new trucks have it also but not as bad as my previous LMM truck
 
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