I just purchased a 2005 F-250 with the 6.0 powerstroke 5 days ago, i put about 500 miles on it with no issues, then yesterday I was taking my wife for a ride in it & went full throttle from about 25 mph-65 mph, when i let off the throttle it stalled & now it won't start again, I did the FICM test i found on here, & that tested out at 47.5 with key in run position & 46-47 while cranking, truck cranks fine but will not start, i can hear buzzing underneath by fuel tank, also buzzes under hood when turning the key to run position, any ideas for a first time diesel truck owner?? oh the thing has 370,000 miles on it also, previous owner said there is a egr delete done to it already, I know nothing at all about diesels, thanks

 

I also cranked it for 20 seconds & the oil pressure gauge came up to where it normally runs, My brother has a scan gauge he programmed & he's coming over tonight, we are gonna test sync, ICP pressure & IPR values, again I know nothing about Diesels, if anyone here can help with some other common things to check I'd appreciate it much, I will update as we continue to do more tests.

 

You are on the right path, check ICP actual and ICP desired, also IPR duty cycle.
If the IPR duty cycle is high/85% / and ICP actual is below 500psi then you have either a high pressure oil leak or a failed HPOP /high pressure oil pump. or just a clogged or failed IPR valve.

 

ICP pressure only went up to 37 psi & the IPR was at 84.7%,
I guess we gotta get to the IPR valve now.

 

pull the IPR valve to see what it looks like first, look for debri on the screen.

 

I just had a similar problem, mine ended up being the IPR, at first I was getting frustrated, but with the help of bobfbigman and some awesome videos on youtube from dieseltechron it really helped. dieseltechron's videos also have detailed footage of each no start scenario and he explains them pretty well, also showing you how to use the Scangauge II to diagnose.

Hope this helps.

 

UPDATE::: Thanks bobfbigman & others who helped me here, Mine ended up being the IPR valve also, I pulled it out & half of one of the 3 sections of screen was gone & when i shined in it with a light it was lodged in the IPR valve, we dislodged it, put it back in & cranked it, when the ICP went up to 866 i quit cranking, went to my Ford dealer bought a new IPR valve put it in & started right up, engine seems to run quieter now, according to everything on the scan gauge everythings working how it should & truck has good power, just seems a little quieter than before.