I have a 20041/2 3500 with AFE intake system, 5 inch turbo back exhaust, BD X programmer, BD exhaust brake and a turbo boost fooler. I am pulling a 38 foot 5er weighing in at 16,500 pounds.

My problem is when I put my foot into it on a good hill (7 - 9%) I am pulling about 34 psi turbo pressure with a 1150 - 1200 egt. at 2400 to 2600 rpm. Then for no apparent reason the turbo pressure starts to back off down to about 18 - 20 psi. When this happens the fuel does not cut back so my egt temp climbs and I am blowing black until I back out of the throttle.

Does anyone one know what would be causisng the boost pressure to drop

 

Waste gate is opening or the programer is de fueling.

That said if you are pulling 16.5 k up a 9% grade and keeping the egt under 1200 you are doing really well.