So I posted this on the cummins forum and DoubleRdiesel suggested In post it here. Here's my original posts.(Truck is deleted with RacemeUltra on 120hp tune all defaults and trans tuning.)
Just had something weird happen. Been driving on this new tune for i guess 4 days now. I went to pull out into traffic pretty fast. Maybe half throttle. Truck took off fine and then I think hit second and fell completely on its face. It felt like it defueled totally or something. Fuel filters have about 400 miles on them so its not that. I let off and accelerated slowly and it hesitated and then drove ok. Next light.
Someone suggested torque management kicked in which made sense.
Then it happened again but this time I got a check engine light and error code for fuel pressure valve activated.
I cleared code but haven't had a chance to drive it hard yet. Ray, I checked and am running default 1850 rail pressure. I changed gauges to monitor fuel pressure and I'm guessing if it a weak relief valve that I should be able to see my max fuel pressure and determine if it's in range or not? Assuming it is a weak valve and needs to be shimmed like Ray suggested, is there any harm shimming or am I safer just replacing the valve? I found a new OEM one on ebay for $160. Thoughts or input appreciated!