I've got an '07 F350, 6.0, no hpo leaks at 150psi. shop air. This thing has to crank 8 to maybe 15 secs. before it starts. The IPR goes to 85% at start. The ICP starts at zero and does a slow climb to start pressure. I've also checked the pressure with a gauge. Same. If I energize the IPR immediately after shut off, the system will hold 125 to 200psi for some time and the engine will start normally. De-energize the IPR and the pressure rapidly drops to 0 and it's back to a long crank. Thanks
Don't think I have a supply problem. What I did find is no oil behind the ICP. I took the ICP out to check it manually and noticed the rail was empty. This was after running the engine for ten minutes or so. The ICP is good. I replaced the HPOP because I was running out of ideas. While it was out, I pressurized the hpo system. No leaks at all at 150 psi for 1/2 an hour. WTF??? Oh, also the IPR is new. Any help is truly appreciated.