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View Full Version : Lq9 Swap bucking under WOT



TorqueMonster007
July 19th, 2021, 02:34 PM
Have a neighbor that does body work. Bought a wrecked 05 2500HD and fixed it. Then had a fella he knows put a Lq9 in it with a BTR truck cam (212/218 @111lsa .553/.553 lift) This said installer had someone tune the truck to basically get it to crank and run. Since my neighbor is a carb guy he asked if I could take a look at it as I have my V2. Attached is the tune I was playing around with. However even before I did anything to it, it will buck like a lean buck as RPM tries to clime about around 4k RPM. It was very slow to apply the power. It almost feels like the fuel pump won't keep up with the commanded fuel. Can somebody take a look at this file and see if anything sticks out that would cause truck to at WOT or harder pedal input acceleration feel like it is holding back and bucking gradually as it tries to gain RPM which is slowly. I did not have time to log any specific PIDs but want to know if anything that sticks out to them right off that could cause this issue. Stock Lq9, BTR cam, manifolds with no cats and CIA. Attached are both files below. The original and the one I have played around with (but have not tried).

TorqueMonster007
July 19th, 2021, 02:45 PM
Possibly a fuel pump issue? He also had been running regular gas and I had him fill up with 93oct to allow fuel trims to relearn with better fuel.