6.0 Runs but not building pressure at ICP
Hello and thanks for looking, I will try to make this short.
Truck ran rough so I scanned with AE - I suspected a H.pressure leak due to cold start but no start when hot.
Tore truck down to do the STC BUT my truck has the old style pump without the fitting so I was surprised because that's where I thought the leak would be. Took a hose and pressurized the lines to find the leak, turns out there was a leak at #2 cyl. Removed wavy rail found seal faulty in injector, RE and RE'd the seal and reinstalled the rail, ( I did not do the tubes or dummy ). Added some oil to the hose going into the pipes to stop leaks and pressurized, waited, no leaks, sweet. tried two more times, no leaks at all.
Reinstalled the pump with new seals. Reinstalled the rest of the parts and fired her up after priming fuel of course. Had a weird ticking noise for a few seconds ( apparently air leaving the system ) and then she ran nicely.
ROAD TEST - no power, dragging an anchor apparently.
Hook up AE and see what the deal is. ICP 1000psi - desired 1500.. hmmm leak maybe ? .. back to the shop, removed ICP and put in borrowed operational ICP - no change.. ok, not an incorrect sensor helping command the IPR.. Check IPR while driving .. 84% oil pressure 1050 desired 1600.. ICP voltage way too low.
Back to the shop. Connect pigtail to the IPR - By the way for anyone looking the solid red wire is +12v - red yellow is the negative.. took FOREVER to find this as most people say just hook up power to both and ground the case ( wrong )
So next applied the shop air 100 PSI,, I hear a small leak, apply power to the IPR it stops instantly, do this 3 times, yup for sure IPR is functioning at least to that capacity. So no leaks at all with the IPR closed.
Hoping but suspecting this must be the HPOP BUT it was building pressure fine before the tear down. I am pretty much resigned its the HPOP .. Can anyone add anything I did wrong or any suggestions ?
I just don't understand why it happened to fail right after teardown..
I also checked the check valve in the oil filter housing, seems free. BUT I have noticed the low oil pressure gauge in the truck takes a few seconds even after it was just running to come back up.. I am using a proper filter and original cap. I am about to go test low pressure oil pump readings next but I suspect I am getting LPO.. I had a friend crank with the filter out and it filled the empty cavity in about 8 seconds.. sound reasonable ?
Any help or suggestions would be appreciated.. Sadly I think I know the answer. Also, are the old style pumps that are being sold now redesigned to resolve some of their failures or are you still getting a "****ty" pump. I can't really update to the newer one without a ton of work and money..