hello I’m have same similar problem with my 2015 pro start international with a Cummins I have to check lights Can this be the answer to my problems
Mine is doing kinda the same thing happening its a manual transmission when I frist take off everything seems fine 30000 psi fuel pressure on high 90psi low but the further I drive the high pressure drops to 15000 to 17000 psi demand and actual still have 90 psi on low and it stays that way until I shut the truck off and start it back up it does go for a bit and goes back to low fuel psi and low power I replaced the the fuel pressure control valve not sure where to go from here tia for any info
Hi. Your high pressure fuel pump has plungers sticking open. I’ve had luck changing the plungers, but I don’t think you can buy them from International parts. I ended up buying a used pump and changing them on the truck. most likely a new high pressure pump is the repair.
Like mentioned, it looks like the high pressure pump is worn out. Good pressure cold, but when hot it is leaking internally due to worn parts. Shutting it down only even briefly allows it cool enough to make pressure again until it gets hot again.