I have a 2003 f350 with 205,000 miles. I have a long crank cold or hot doesn't matter. About 8-10 seconds. When truck starts it runs fine and the hpop will create above 3000 psi at WOT. The ipr % is between 70-80% if I can recall correctly. At idle the ipr % is 30 when cold. The screen was clean on the ipr. If I turn it off and start it up right away it starts fine but let it sit for a 1 min it has the extended long crank. The HPOP was replaced about 30,000 miles ago due to not making enough pressure causing a no start. I pressurized the system with 120psi of shop air and closed the ipr valve and the only place I hear air coming from is the oil filter housing. This is how I diagnosed the original pump being bad but it also didn't make enough pressure about 400psi. It's just bubbling sound not like a hiss or anything. I pulled the hpop off and put shop air to the top of the pump and can hear air coming out of the suction hole at the bottom of the pump. Also a little out of the front seal which I know is acceptable. Is this causing the system to leak down and causing a long crank? No air should leak back thru the pump. correct. I think the pump is bad cause it leaks down the oil but then again it still make good pressure and only 30,000 miles on it. I replaced pretty much every seal in the system and the icp sensor w/ connector (second time also). So think the pump my be the problem just can believe that yet cause of the low miles on it. need to hear it from someone with experience. Thanks in advance.

 

When cranking what is your ipr% and icp psi when the issue occurs? also whats your ficm voltage. is it an aftermarket (orielly or autozone) pump or motorcraft? the correct way to test for leaks would be using this https://www.amazon.com/AccurateDiese...pr+air+fitting

I never test through the icp fitting. this way is a lot better cuz now air can only go 1 direction and that's through your oil rails. i've seen air leak out of the top of injectors.

 

I Found NO answer on if air should flow back thru the pump. Mine did and another you tube video I watch the guy replaced his pump and had the same thing. But another video a guy showed his held pressure. My theory is the system should hold atmospheric pressure when the ipr valve has no power it is open dumping oil back to the crankcase. After replacing all my top injector seal (3 I know fail air test), stand pipes, new nipples and seals from hhc diesel, top j tube on pump and new pump seals I still had this extended crank. Some stuff just changed due to mileage. Never full put the truck back together tho. Just ran with valve cover off. Got fed up and just put everthing back together and did and oil change. Don't know if the oil was braking down. no sings of coolant or smell of fuel. Truck starts great now 30% ipr when cold and 23% when hot. According to diesel tech Ron (R.I.P.) on you tube. Guy knows his stuff he said 30% cold and 20-25% hot ipr should be. 3600psi at WOT which is correct. guess what I am trying to say is if the pump makes pressure and you air test it and it you hear air from the oil housing don't replace the pump. Hope this helps somebody.

 

Any luck on finding the problem? I'm having exact problem

 

Any luck on finding the problem? I'm having exact problem