Ran Great Last Night - No High Pressure Oil Pressure This Morning - No Start

[toddman35]

I put a used engine in the '02 about a month ago and have been getting close to wrapping up the project. Yesterday was the first day that I got any road time (about 15 miles) on it, but I've been starting the truck up almost daily for the past couple weeks and moving it in and out of the shop/around the parking lot. Its always started up fine.

I drove it home last night and much to my surprise, it wouldn't start this morning. It didn't even try to fire. Plugged in AE and checked out the ICP and IPR Duty Cycle. ICP was reading ~200 max while cranking and the IPR went up to 98% as expected.

-HPOP reservoir is full
-Its got a slow leak from the turbo area, nothing like a blow high pressure oring though.
-New batteries
-New starter
-New injector O rings
-OBS Single shot injectors & DP Tuner tuned for them
-New Head Gaskets
-Turbo Rebuilt & new o rings there
-5w-40 Synthetic
-Hpop bolt torqued slightly above spec
-No significant oil leaks on ground
-New ICP last year - no start with it unplugged either

I have had some high pressure pump issues with this build though. I originally had the super duty pump on it from my orig engine but that may have been the cause of the original failure as it didn't create any pressure

I swapped in the OBS pump off of the "new" engine and that generated great pressure on the first crank. A few cranks later, it wouldn't generate any pressure.

Bought a used low mileage remanned 17* SD pump and swapped that in, its made great pressure for the last month and 150 or so starts. Until now.

Whats going on here? Would an injector O ring suddenly fail over night? It was running fine last night when I parked it. I'm getting ready to pull whats left of my hair out over this thing.

[jesilvas]

LPOP went bad all of a sudden? Does the regular lpo gauge build pressure cranking?

[toddman35]

Originally Posted by jesilvas

LPOP went bad all of a sudden? Does the regular lpo gauge build pressure cranking?

It does show up on the gauge after cranking.

[alberta 7.3]

Do you have a spare IPR that you can swap in? My IPR took a dump spontaneously last winter just driving down the road.