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VACARELLAB
April 11th, 2009, 02:07 PM
Anyone who knows something about the lb7, look at this data log and see if you can help me figure out what is wrong. Truck falls on its face, then comes back, more when pulling my boat or camper, notice the throttle position and the boost and everything else, the log starts when the problem starts and continues for a while. Please reply or call me.

Patrick
205-283-0433
Nemo
April 11th, 2009, 07:50 PM
Do you have a Fuel pump of any kind? your Fuel Rail Pressure jumps around a lot... Someone Else should chim in on this...

-Nemo
Max Power
April 12th, 2009, 12:48 AM
Does it always do it in 5th gear around 70-80mph?
VACARELLAB
April 12th, 2009, 01:16 AM
Yes ther is a lift pump from superduty on dieselplace, and is seems to be in higher gears but sometimes with my camper its in first also the wierd thing is, its like someones flippng a switch its fine one minute and the next its not.

A few other notes, mods- suncoast stage 4, afe stage 2, allison 5 to 6 speed conversion,
VACARELLAB
April 12th, 2009, 01:17 AM
And also truck will slow to 20mph b-4 it comes back around sometimes
GMC-2002-Dmax
April 12th, 2009, 10:10 AM
Anyone who knows something about the lb7, look at this data log and see if you can help me figure out what is wrong. Truck falls on its face, then comes back, more when pulling my boat or camper, notice the throttle position and the boost and everything else, the log starts when the problem starts and continues for a while. Please reply or call me.

Patrick
205-283-0433

Is it a 2001 by any chance, if so full flash to a 2002 OS, I can supply a base tune if you give me truck specifics.

It looks like the mm3 of fuel is dropping from commanded to around 32.5 mm3 log from 1530 to 1550, it appears you are hitting a limiter table, perhaps a overboost, does it have any codes ???

Maybe change your fuel filter, dropping rail psi is a sign of a fuel restriction.
VACARELLAB
April 13th, 2009, 12:41 AM
It is a 2004 lb7, im wondering if its showing up more with modified tunes, we disabled the egr and some other changes but when i put it back to stock it has not done it yet please advise.............
GMC-2002-Dmax
April 13th, 2009, 11:16 PM
It is a 2004 lb7, im wondering if its showing up more with modified tunes, we disabled the egr and some other changes but when i put it back to stock it has not done it yet please advise.............

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