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Cant peel or brake torque - Help!

Old Mar 10, 2008 | 09:59 PM
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Unhappy Cant peel or brake torque - Help!

Ive posted this over at HPTuners as well.

I have a 2002 Silverado 1500HD LQ4 6 liter, Built 4L80 with 2500stall, and magnaflow exhaust. Im a fairly experienced tuner with HPT, and I have my abuse mode and all TM turned off. I cannot at all peel this damn thing out or brake torque it at a stop sign or anything. All it does when i nail it, is flash up to the tq converter stall (2500) and start revving and starting out from there. It will break off nice around a corner or pulling out in traffic with the wheels cut a bit, but thats the extent of it.

I have tried just about everything in the tune file and connt figure this thing out. Posted below is the tune if you guys want to check it out. I have put some shift torque management in for the shifts just for good measure because the gains are about non-existent.

Also this truck is rolling on 'nicely' worn BFG Commercial T/A's. Thanks to any and all who help!
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current.hpt (469.3 KB, 172 views)

Last edited by gman4dx266; Mar 10, 2008 at 10:20 PM.
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Old Mar 11, 2008 | 07:07 AM
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Tune doesn't look to be the problem.
heavy truck with 4l80, good rear brakes, and 3.73s might have something to do with it.
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Old Mar 11, 2008 | 08:57 AM
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Eh...Idk you'd think that even not brake torquing it would just go like a bitch when you mash it from a stop. Ive gotten my *** spanked doing a burnout by a stock 03 2500HD 6.0/4l80/373's so i dont know what gives. Thanks though!
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Old Mar 11, 2008 | 09:26 AM
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Don't know if you have access to this in HPT........

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Old Mar 11, 2008 | 09:42 AM
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Yeah, I think thats Abuse mode. I have the master switch set to disabled.

By the way, truck throttle body is cable driven, not ETC. So not sure that would even apply, going by what your EFI Live screenshot says "...reducing pedal opening on ETC vehicles..."
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Old Mar 11, 2008 | 08:10 PM
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Originally Posted by gman4dx266
Eh...Idk you'd think that even not brake torquing it would just go like a bitch when you mash it from a stop. Ive gotten my *** spanked doing a burnout by a stock 03 2500HD 6.0/4l80/373's so i dont know what gives. Thanks though!
I feel your pain. I've also got an 02 1500HD using HPT. I was under the impression that all 2500 and 2500HD had the 4.10's, correct me if i'm wrong, but I have yet to find a 2500 with 3.73's, and everyone can smoke there tires but me. BTW what size tires? I'm running 285/75/16
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Old Mar 11, 2008 | 08:14 PM
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Originally Posted by S H E R M
I feel your pain. I've also got an 02 1500HD using HPT. I was under the impression that all 2500 and 2500HD had the 4.10's, correct me if i'm wrong, but I have yet to find a 2500 with 3.73's, and everyone can smoke there tires but me. BTW what size tires? I'm running 285/75/16
I want to say you can get 373's in a 2500/2500HD, but im not for certain.
EDIT: If memory serves, the only way you can get the gear of your choice (373 or 410) is if you get the 8.1 in a 2500. Otherwise with the 6.0 you're stuck with a 410 in the 2500. So, you're probably correct assuming you looked at all 2500's with the 6 liter. This is from memory though, like i said, not sure.

Im running stock tire size, 245 75 16.

Since you're using HPT, can you tell me what operating system you're running by chance? I have a thread going on on the HPT site about a torque converter issue and i think this OS is complete **** to be honest with you, OR some options are left out in HPT. I dont know. In short, im unable to keep the tcc locked with anything below 5% throttle, but thats another story.

I'm running OS 12212156

And I mean come on, I know its a heavy truck, but its a freakin SIX liter!
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Old Mar 11, 2008 | 08:20 PM
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Nothing jumps out at me. I don't see a Brake Torque Field so it doesn't appear there are any changes you can make there.
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Old Mar 11, 2008 | 08:23 PM
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I have an HPTuners.com thread with scans posted which you can watch. there are two, one from a stop and one brake stalling.

http://www.hptuners.com/forum/showthread.php?p=120822
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Old Mar 11, 2008 | 09:04 PM
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Well that didn't tell me too much but in the Brake Stall log it appears that as soon as you hit 100% TPS (about 1800 rpm) the output shaft starts to turn as does the output shaft. That means the driveshaft is turning. Then for a brief second the input shaft speed goes back to 0 before climbing again. The vehicle speed sensor then registers 1 mph so the wheels have to be turning a bit. Shortly thereafter it appears you release the brake and away you go. Are you saying it won't spin at all or just won't "light them up" when you are brake torquing?
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