Classic cranks but doesn't start problem
 

My 96 psd won't start. Yesterday I left the shop to head home, the truck fired right up moved about 20 feet and shut off like I turned the key off. Now it cranks and cranks but won't fire. It isn't getting any fuel, no raw fuel smell or white smoke out the pipe. Put the scanner on it , no codes (p1111). Oil level in HPOP resevoir is OK. Changed the CMP but that didn't help. Read cranking RPM,VPWR,ICP,FUEL PW on the scanner. V PWR and RPM are within spec. ICP is only 165 psi and FUEL PW is .42 mS. Where do I go from here.....ICP sensor, IPR valve, HPOP? Truck has 140,000 miles. The shop manual says replace the IPR with a known good one first, OK for a dealer mechanic with a big parts room on hand, an expensive way to troubleshoot if you are paying the bill.

did you try the CPS? in alot of cases this is it.

Did you try starting it without the ICP hooked up? ICP is low, I believe it needs somewhere near 500psi to start... Maybe need to clean the IPR... Here is a write up for that in case you need it.

Did the CPS already, plus the RPM signal shows the sensor is ECM.

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Yes I did try to disconnect the ICP, didn't start. With ICP disconnected, ECU showed 2400+ psi (max default pressure).

IPR valve??

The IPR is the next stop on this trip. Is there any way I can tell if the ECM is sending the IPR the correct signal? I hate to disturb it for no reason.

I changed the ICP sensor still didn't start so I changed the IPR and if fired up. The pressure at idle was 580 psi, a little on the low side and the idle is a little rougher than I remember. When I had the ICP out it looked like the rail wasn't totally full of oil. Will the air in the oil system work it's way out or is there a method to bleed the system?

It will work its way out.