I have a 1997 F350 auction buy, tinker project. To make a long story short have done inj. orings, glow plugs, valve cover gaskets several other things had it starting and running what I thought to be good but had hot start problem. Haven't fooled with it in a while have read several different places that it was most likely the IPR causing hot issue, found a link to dissassemble and clean so I did that, the truck hasn't started since reassemble/reinstall. Have 12V at connector but can only build 400 psi hop cranking which I know I need 500. Pilot valve was smooth when plunged, the info said to tighten internal screw about as much as computer screw I did what I judged to be that, the piston would drop in IPR and if you didn't shake real hard as to slap bottom it out it would slide freely but would be stuck if put togeather then dissassembled have to rap on desktop to free piston, is there something I missed about reassemble or do I just need to find new IPR and hope it fixes lastest problem of no start at all.

 

Sounds like one of two things, foreign debris or burr on piston. As far as cranking pressures you would have to watch the IPR DC% vs ICP pressure to know about the health of the IPR (given that no other issues exist). Most likely it can be sorted out without replacement if it was working before disasembly. I'm not a fan of tearing them completely down, it usually leads to more problems with my bad luck! I just usually remove the orings and soak it in carb cleaner and blow it out several times.