I am fairly new to HP tuners and dont have much experience with tuning the GM stuff so bare with me.
I have a 2014 gmc sierra with a D1-sc procharger, big red race valve and long tubes headers. 4.25 pulley makes 10ish Psi tuned on 93. stock cam just bolt on stuff. I assume most of the file would be similar to stock drivability wise so it confuses me to why this problem is occuring.
The truck has been to a few reputable tuners in south florida and cant seem to get the issue straightened around. The truck seems to run fine aside from the issue it has on a long decel. For example merging on the highway, a long deceleration with the AC on, as the truck slows down, the short term fuel trims jump to approx. 40% and stay there until i come to a stop. as i come to a stop the truck realizes the fuel trims are pig rich and tries to compensate causing the truck to surge and eventually stall. I usually can throttle back into it to get the fuel trims to return back to normal or drop it into neutral and clean it out and the fuel trims will drop back down. It doesn't occur all the time but it does it quite often and will even do it occasionally with normal city driving. it seems like it is more common with the AC on, when the AC is off the truck drives usually without a problem. Ive reached out to multiple tuners trying to get advice but most of the time i get the "it needs to be flashed back to stock" and wanting to charge me for a full retune when it could be something simple. The truck was originally tuned by Fasterproms and after some playing around and a couple retunes is when the problem started occuring. after many changes to the tune we couldn't figure out what was causing it. So i took it to redline on the east coast of florida and explained my issue. They said they can fix it that its probably something simple. so redline tuned the truck and claimed to fix the problem but go figure the problem still existed after being charged for a full tune. i was told we could datalog the problem and remote tune since i lived far from redline but eventually never got any adjusted tune after many calls and emails with many excuses but no answers. Im not here to bash any tuners of their work i just need help with possibly getting different opinions on something in the tune to adjust that could be causing the problem. Im so frustrated with the truck that ive been tempted to sell the blower and put it back to stock. I cant let anyone really drive the truck as it can be unsafe when it starts surging and stalling in traffic. Im running out of options and would greatly appreciate any advice if someone can look over the tune and datalog and maybe shed some light on my issue. thank you in advance! I do have HP tuners and the ability to make changes to the tune myself but i do not have the stock file for the truck. I attached the current tune in the truck along with the datalog of the truck when it surges. the surging occurs at the end of the log when i merge off the highway.
redline tune datalog.hpl2014sierraRedlineTune.hpt
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Originally Posted by Bcunningham1
