Low hpop pressure

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Apr 9, 2025 | 07:52 AM

Tarzan369

Thread Starter

6th Gear

Joined: May 2017

Posts: 6

Likes: 1

Low hpop pressure

Okay really needing some help here freshly rebuilt motor 99 7.3 ran like crap for a day or two ended up getting a new IDM and haven't been able to start it again since only showing about 185 PSI on high pressure oil pump on Torque Pro I unplugged the IPC sensor on the gauge it shows 3000 psi but still will not start changed out the pump hpop pump with another one that I had still same thing went through changed all injector O-rings still same thing waiting on a gauge to come in to try and deadhead the pump and just see any other suggestions would be greatly appreciated thank you

Last edited by Tarzan369; Apr 9, 2025 at 06:45 PM. Reason: Don't need any more

Apr 9, 2025 | 08:53 AM

pvdiag

Tuned

Joined: Apr 2004

Posts: 428

Likes: 72

From: Aroostook County, Maine

One of the quickest checks for this type of situation is to see if there is oil in the HPOP reservoir. If not, then efforts should be directed to the oil circ system - oil pan pickup, the low pressure oil pump (LPOP), or something blocking oil flow. Checking oil pressure on the rez would be next step if there is oil there. These engines will not start if there is not enough oil getting to the HPOP.

Apr 9, 2025 | 10:34 AM

Tarzan369

Thread Starter

6th Gear

Joined: May 2017

Posts: 6

Likes: 1

Yes sir there is Will in the reservoir took it drained it out when I changed out pumps everything seemed to be fine filled it up it's not leaking out and not coming out of any injectors that I can see like I said I just replaced all the injector o rings thinking that that's where I was losing pressure that didn't fix my problem wondering what else it could be all new sensors IPR ICP crankshaft position sensor all new Motorcraft

Apr 9, 2025 | 03:50 PM

udsuth78

Lead Driver

Joined: Oct 2005

Posts: 6,129

Likes: 1,919

From: Ponca City, OK

Have you bled the new pump? What's the time frame of all these events? Sensors all Motorcraft?

Apr 9, 2025 | 05:34 PM

Pikachu

Lead Driver

Joined: Jun 2004

Posts: 6,326

Likes: 585

From: Amarillo, TEXAS!

Did you double check the solenoid, spacer and nut are still secure on the IPR valve?

Apr 12, 2025 | 09:36 PM

Kintla

Tuned

Joined: May 2021

Posts: 363

Likes: 121

From: Montana

Are you making sure the drive gear is fully seated on the shaft of the HPOP before torquing the drive gear bolt?

And, as you probably already know, sometimes it can be a bear to get the truck to start after opening up the HPO system. I've had times it took lots of cycles of cranking/resting before it caught.

Sometimes they'll fire right up with minimal cranking.

Apr 14, 2025 | 01:48 PM

dammitman

Cross-Country

Joined: Mar 2025

Posts: 76

Likes: 26

From: 52227

i figured out that after removing injectors and all that to refill the high pressure oil channels on the heads by removing the sensor at front of drivers side to fill it and i think the second plug from front on passenger side. you must get creative as to how to fill i have used mini funnel, but learned to keep a couple cheap ketchup style squeeze bottles filled with the 15w40 oil and just pump in the plug holes. i never had one ever not start right away after that.