I found my warm and cold start data.

Cold start:

Warm start:

 

You have classic HiPres Oil symptoms that show-up in older HEUI system once the Oil Warms & Thins. And the diagnoses would be that the O-Rings are the first suspects. Kinda Classic symptoms

OK so the rings are done, and you saw No Change at all? Even at first? I would maybe think about pulling the valvecovers and looking for signs of a cut or damaged ring that's bypassing (squirting) oil from an injector. Did you use the Right rings? (Alliance).

Next would be a sticking IPR maybe, although not related to thinner oil, as everything heats-up, tolerances shrink, the IPRs pintle can bind and hold Open, allowing HiPres Oil to bypass. Again, I would hope that the IPR was Not Aftermarket (was the ICP? - and btw - Oil in the connector is NOTHING to worry about, I don't where this nonsense got started but it's Everywhere!) The other important thing to consider is that there is No Feedback from the IPR. That is, all you can read is what the PCM is commanding the IPR to do. If Stuck, it can be actually only 14% closed (bleeding Lots of pressure) while your IPR reads 65%

To summarize, colder thicker oil, along with rubber parts that are harder because they're Cold, gives you Good enough pressure to start (but even Cold your IPR is having to close-off more that it should have to in order to make that pressure). Hot, thin oil, along with softer, more pliable rubber parts once they heat-up, and everything goes to $hit (even Maxing-Out the IPR, fully closed so it bleeds the least amount of pressure off, can't get you there with enough pressure to meet the PCMs Starting threshold of around 500psi).

As for Fuel Pressure, there is actually a link to HiPres Oil issues and explained well by Ron but, I don't think you could get a No Start from it ->

 

Thanks for the quick response! I was kind of stupid when I bought orings. I didn't want to wait too long so I bought the ones with the best reviews on Amazon, not alliance or motorcraft. I don't have any paperwork on the IPR so I don't know what he used or if he even actually replaced it, but I have the shop paperwork for the ICP and it is OEM. After the orings if there was any change, it lasted for less than 10 minutes.

I'll pop the valve covers off again and look for oil leaks and if I need to I'll order the correct orings and redo them. While I'm in there I'll check the uvch more closely. I noticed the are small o rings on the oil rail plugs when I pulled them to drain the rails. Would it be a good idea to replace those while I'm in there again?

 

I also forgot to mention I have a pretty decent oil leak into the valley between the heads that leaks down the back of the engine.

 

That oil leak is pobably a leak from the back pressure actuator, in the pedestal, under the turbo. I know its kinda hard to see, but if it only leaks when its cold and not when its hot, that is probably it. Easyist fix is to unplug it, best fix is to delete it with a new pedestal.

 

Here is another piece of the puzzle: I had to replace cups 3 months ago, truck was running/idling well at the time. Decided to put in KC turbo's street setup while I was in there (WOW! But that's for another discussion). Had some issues but chased it down to the UVCHs and it runs well now, but idles poorly once it warms up.

Called Full Force Diesel (the ones who supplied the injectors) and they thought it was the ICP sensor. They suggested unplugging the sensor (at idle, don't try to drive it) and let it idle on the default value, 725psi once it is warmed and stable. instantly it idled fine. So I replaced the original ICP sensor with an O'Reiliy, then an Auto Zone, then a Ford (that was one of the lower priced ones but still $200) and still the same rough idle. There may have been some slight improvement with the Ford one but not significant. Unplugged it again this morning and its still the same: Good unplugged; idle steady-ish 675 - 700, ICP 725psi. Plugged in; surging, running rough and sounds like I'm about to throw a rod, ICP pressure varying between low 500's and low 700's, idle RPM varying between mid 400's to mid 800's.

One thing I did notice, the CTS3 says the throttle position is always in 'Partial' position regardless of how much foot is or isn't in it. And it throws a soft code when unplugged but the CTS says there are no codes!?!?

IDEAS???

 

Here is another piece of the puzzle: I had to replace cups 3 months ago, truck was running/idling well at the time. Decided to put in KC turbo's street setup while I was in there (WOW! But that's for another discussion). Had some issues but chased it down to the UVCHs and it runs well now, but idles poorly once it warms up.

Called Full Force Diesel (the ones who supplied the injectors) and they thought it was the ICP sensor. They suggested unplugging the sensor (at idle, don't try to drive it) and let it idle on the default value, 725psi once it is warmed and stable. instantly it idled fine. So I replaced the original ICP sensor with an O'Reiliy, then an Auto Zone, then a Ford (that was one of the lower priced ones but still $200) and still the same rough idle. There may have been some slight improvement with the Ford one but not significant. Unplugged it again this morning and its still the same: Good unplugged; idle steady-ish 675 - 700, ICP 725psi. Plugged in; surging, running rough and sounds like I'm about to throw a rod, ICP pressure varying between low 500's and low 700's, idle RPM varying between mid 400's to mid 800's.

One thing I did notice, the CTS3 says the throttle position is always in 'Partial' position regardless of how much foot is or isn't in it. And it throws a soft code when unplugged but the CTS says there are no codes!?!?

IDEAS???

I know this is an old post, but I was wondering if you solved your problem.