Hey guys, I am new here, first post so here's what I got. 2007 2500 dodge 5.9l cummins. I got involved in this truck after the fact so it had a bunch of stuff replaced that probably wasnt needed. Truck has 202,000 +/- miles, It runs great for about 15-20 mins, after that time the actual fuel pressure starts dropping-ever so slowly- setpoint is around 6100psi and actual psi is within 600 until it starts dropping. Right brfore it starts the actual pressure gets erratic, varies within 1000 psi above or below set point. It takes about10 minutes or so before it really goes down. Around 2100psi it dies, as it should. When this happens it starts smoking, not really black but not really white either. Now on to the list of parts that another guy has replaced----ALL 6 injectors and tubes, lift pump_in tank- fuel filter, FCA, fuel pressure sensor. The guy that was working on it quit so Its all my baby now. eeeek! Well I scanned codes and have P0148 Fuel delivery error. I double check everything (except for connector tube nuts) that just occured to me to check. I run the fuel pressure relief valve test and at idle I have fuel coming out, which I know should not happen. I had the luxury of having another one in the shop, so I swapped them. No change. However the one I took off had fuel in it, so Im not 100% sure it is the best to try, but that truck had other issues other than running. When the trucks dies it will not restart until it sits for about 30 mins and then she will crank up and run like nothing is wrong, until the pressure starts dropping, then it starts all over again. I have worked on hundreds of these things and thought I had seen it all, and this goofy problem comes along. Maybe I am overlooking something or cant see the woods for the trees but I am stumped on this one. I can clear the DTC and it will not return until it starts acting up. If anybody has seen this I would love to hear about it. Thanks in advance and if ya'll have a question for me just ask. Thanks again.

 

Well i finally got this thing whooped! Turns out that ALL the injector hold down bolts were WAY to tight along with the connector tube nuts. I removed all injectors, reseated them along with the tubes. What I figure is they installed the injectors tightly and then the tubes and they were not lined up properly. After I got it put back together my pressure never varied more than 300 psi+/- and never dropped after 2 hrs of running and driving. I HATE going behind someone else. thanks for looking