New to the forum so I hope I’m not bringing up old issues.
I am having issues with my truck starting hot or cold, really scratching my head.
I have two new batteries that are well charged.
my issue seems to be an extended crank before ICP will build to 500psi. Once it does build to 500 it cranks immediately, pressure jumps to 1500 at idle and it runs fine, not lacking power, no smoke nothing strange at all.
i have done a dead head test with a mechanical gauge on the hp oil line and the other plugged and it seems to build pressure slightly quicker but not much faster at all. I tee’d the gauge in-line and it all matches what my scan gauge says. By long cranking I’m talking 45-90 seconds straight. [yes I already melted down an old starter being impatient) IPR percent is 50+ while cranking, and immediately drops to 14% when idling. The IPR is brand new.

i also pulled the valve covers to look for injector o rings possibly leaking by. I see nothing. So I air tested by blowing 120 psi into the oil rail with a rubber tipped pneumatic blower. No signs of any leaks.....

i thought I was onto something when I noticed the HPOP reservoir was draining down over night. I found that the base gasket on the reservoir was toast. I had to order one so in the mean time I RTVd this gasket and now it leaks down but no where near as fast. So. I doubt it’s an oil supply issue as the truck struggles to build pressure whether the reservoir is full or empty.

I did discover that if I get the truck running and shut the key off and immediately put it back to the run position everything will hold in the hp oil system at 500 psi and if I touch the key it will fire immediately.
if I turn the key to off. all the pressure bleeds down to 0 very quickly. (Which I have read is normal (Maybe that’s the IPR opening with no power?)) then it takes a long time For pressure to build. The key only has to be off for maybe 5-10 seconds for it to struggle to restart. hot or cold

oil and filter is brand new, no change,

removed the check ball and spring (seem totally fine) which is another interesting subject . A lot of people want to point at this and the LPOP as an issue but the further I dig in to the reservoir drain problem they appear to come thru a stand pipe in the reservoir that might allow a small amount of fluid drain out but by no means ALL the fluid. The reservoir is still at least 3/4 full below that stand pipe so I would think the truck would fire easy but then maybe struggle to run for a second while that reservoir Re fills In a weak LPOP or failed check ball scenario? Am I wrong about that? HPOP seems to be fed from the lowest part of that reservoir and oil from LPOP seems to enter from the top??

im starting to think my HPOP is just struggling to prime itself?? The HPOP is only a year old with really low miles on it so I was surprised to start leaning in that direction. also during the dead head test when the HPOP finally grabs it rockets to 3000+% so it seems like it is marketing the pressure just taking a long time to get there????

 

what is oil pressure during the HPOP having no pressure?

Is the nose f truck tipped up when parked? if yes then Have you tried to add in an extra quart or two of oil?

if any air is introduced into the HPOP lines, it can make for a hard start

LPOP pickup tube has been known to crack and can do exactly what you are describing but lets rules out everything else first