Starts Up cold wont start hot

[Ricemiester]

I got a 6.0 06 truck its got 185k on it and it starts fine when its cold but when it warms up it wont crank and the HPOP only builds around 100psi. I replaced the stc fitting on the pump and all orings inside there, i had the engine apart a while back and i messed up by replacing orings on one of the fittings in the drivers side valve cover. Replaced all orings on drivers side it still does the same thing. My ? is has anyone seen an HPOP act like this? any insight would be nice thanks!!

[fordmasterdieseltech]

sounds like either the bottom oring on the dummy plugs or stc fitting. if you have done the fititng already, you need you pressurize the high pressure oil system with shop air and check for leaks.

[Ricemiester]

so u dont believe it is the high pressure pump? i replaced the dummy plug on the drivers side ill check the one on the passenger and replace the pump.

[Ricemiester]

Update to my post. Replaced the high pressure pump, replaced both dummy plugs, the long stems were replaced not even 5k miles ago when i studded the heads, all orings are new maybe one of the seals on the injector is bad? This time im gonna try to run it w/o the valve covers on it, any tips would be great TY!!

[m-chan68]

Originally Posted by Ricemiester

Update to my post. Replaced the high pressure pump, replaced both dummy plugs, the long stems were replaced not even 5k miles ago when i studded the heads, all orings are new maybe one of the seals on the injector is bad? This time im gonna try to run it w/o the valve covers on it, any tips would be great TY!!

How long did you crank the engine over, after the repair? Have you air pressure tested it? Does oil fill up the oil filter housing rapidly when you crank the engine over, with the filter cap removed and the drain valve depressed with your finger?

STUPID QUESTION. When you replaced the high pressure oil pump, did you remove the red plastic protective end cap from the underside of the new pump (assuming you obtained and installed the Ford 5C4Z-9A543-B pump)?

[Ricemiester]

after i did all of the repairs the engine ran. just after it warms up a bit the engine will not start. you can run it all day but it will not start after u shut it off. i can go out there now and crank it but when its gets warm i hook my scanner up to it and it only pumps up to about 100psi. just seems odd that if it had a leak it would shut off at one point

[Ricemiester]

and after the engine does warm up if u crank it long enough the oil pressure guage will register eventually

[purplehorn1977]

sounds like maybe a bad ipr valve. that is shorting when its warm

[Ricemiester]

I may try to change that while im in there. I have the old one. Now another question? I put shop air to the system and hear leaks only in the passenger side valve cover. I isolated the block by putting another dummy plug in the other hole that feeds to the tube in the block. I found a bad oring in one of the injectors it was rolled. Now when i put air back to it it seems like air is coming out of the small holes on top of one of the injectors. It's not alot of air but it does still leak is that normal? also when i crank it over hot. when you turn the key on the IPR % is at 15% when u crank it it jumps to 85% now i have another 05 truck and i did the same on it but it only jumps to around 25% to 32%. Is the IPR just trying to feed it more oil or is it an IPR problem

[fordmasterdieseltech]

85% ipr is maxed out, so somewhere you have a massive high pressure oil leak. you need to apply compressed air into the icp port or the port on the high pressure pump and then locate tthe leak from there. m-chan is corrrect, ford started putting plugs in tthe bottom of the pump during assembly. sometimes thtey gett pushed back into the pump and if you dont know its thtere you wont see it. may want to recheck it