Ford Powerstroke Diesel Forum banner

Need the big brains on this problem.

2210 Views 26 Replies 10 Participants Last post by  bismic
I need all of the Big Brains on this one. Here’s the problem. I just finished rebuilding my 6.0L. Won’t start. I’m not getting hpop pressure.
known screw ups are:

Primed/cleaned hpop pump in a bucket of clean oil. Good output w/drill running pump. Installed pump onto engine. That was about a year ago.

replaced both hpop manifolds. Installed dry right from the packaging.

I now know that I have a ton of air in the hpop system. Icp actual upon cranking- 1.5psi.
Removed icp sensor and manually filled passenger side manifold with oil. Removed drivers side valve cover and manually filled manifold through plug at the top of the manifold.

reassembled engine. crank/no start. This time icp actual was 953psi.

here’s the strange part. snap-on interphase tool shows icp pressure at 953psi. Icp sensor was removed from engine. How is the OBDII port reading icp pressure with the sensor out?

Also, low pressure gauge on dash doesn’t come up. Oil filter housing pumps up pretty quickly, so I know the low pressure side is working.

Is there a way to purge the air from the hpop system?
1 - 20 of 27 Posts
Well, I know you asked for the "big brains" and that's certainly not me, but in the meantime, here's my thoughts, having just finished an engine swap and HPO system work.

If the HPO system has been drained, it will take a LOT of cranking to prime it. I cranked mine long enough to drain my brand new batteries before it even tried to fire.

I would first pull the FICM relay out, since cranking is quite rough on the ficm. Sounds like you have a way to monitor ICP and IPR, so keep an eye on them while you're cranking. With an empty system IPR should be ~85%, meaning the IPR valve is allowing full pressure through. ICP will be low, probably zero until you get most of the air purged out. Once you see ICP above 300-500, go ahead and put the ficm relay back in and try to start it again. The truck is programmed to not fire the injectors until it sees ICP above a certain value, around 500psi, I think.

As for the ICP reading with the sensor unplugged, If I'm not mistaken, when the computer doesn't see a sensor input, it uses an inferred value within the acceptable starting range, thus your 953psi.

Hopefully this helps, and maybe someone more knowledgeable can weigh in and help you out (and correct me if I'm wrong).
See less See more
Well, I know you asked for the "big brains" and that's certainly not me, but in the meantime, here's my thoughts, having just finished an engine swap and HPO system work.

If the HPO system has been drained, it will take a LOT of cranking to prime it. I cranked mine long enough to drain my brand new batteries before it even tried to fire.

I would first pull the FICM relay out, since cranking is quite rough on the ficm. Sounds like you have a way to monitor ICP and IPR, so keep an eye on them while you're cranking. With an empty system IPR should be ~85%, meaning the IPR valve is allowing full pressure through. ICP will be low, probably zero until you get most of the air purged out. Once you see ICP above 300-500, go ahead and put the ficm relay back in and try to start it again. The truck is programmed to not fire the injectors until it sees ICP above a certain value, around 500psi, I think.

As for the ICP reading with the sensor unplugged, If I'm not mistaken, when the computer doesn't see a sensor input, it uses an inferred value within the acceptable starting range, thus your 953psi.

Hopefully this helps, and maybe someone more knowledgeable can weigh in and help you out (and correct me if I'm wrong).
Thank you for the quick response, Bohemian Engineer. Approximately how long time wise did your engine take to fire up? I ask because I’ve run my batteries down three days in a row trying to purge the air out of the system. I was considering buying new batteries. I’ll definitely pull the FICM relay tomorrow before my next attempt.
Thank you for the quick response, Bohemian Engineer. Approximately how long time wise did your engine take to fire up? I ask because I’ve run my batteries down three days in a row trying to purge the air out of the system. I was considering buying new batteries. I’ll definitely pull the FICM relay tomorrow before my next attempt.
Not sure exactly how long I cranked it, but I'd say a good 4-5 minutes (not all at once, lol). Is yours the 03/early 04 motor, or the 05/up? The later ones are notorious for HPO leaks. I suppose if you had a big enough leak it could cause a crank no start. You might also want to check your ficm voltage and all wiring, grounds, etc. Seems like no matter how careful we are, with a big project like an engine r&r, we always miss something stupid.
I may be stating the obvious here, but just so there's no confusion, the truck will not start with the ficm relay removed. I would only leave it out while you crank it to build ICP. Then put it back in to try starting it.
With icp unplugged the PID will read a default value. Reinstall the icp and crank for 10 seconds at a time, let the starter cool off and keep doing it for 4 or 5 cycles. If ICP never comes up I'd do an air test.

Sent from my SM-A505U using Tapatalk
  • Like
Reactions: 1
Not sure exactly how long I cranked it, but I'd say a good 4-5 minutes (not all at once, lol). Is yours the 03/early 04 motor, or the 05/up? The later ones are notorious for HPO leaks. I suppose if you had a big enough leak it could cause a crank no start. You might also want to check your ficm voltage and all wiring, grounds, etc. Seems like no matter how careful we are, with a big project like an engine r&r, we always miss something stupid.
I may be stating the obvious here, but just so there's no confusion, the truck will not start with the ficm relay removed. I would only leave it out while you crank it to build ICP. Then put it back in to try starting it.
It’s an ‘05 engine in an ‘04 chassis. I didn’t make the swap. I bought it like that.
I feel like it is something stupid that’s right in front of my face but I’m not seeing it. LOL.
All components of the hpop system are brand new except for the pump and branch tube. Both of which were checked over for damage, functionality, and any cracks. All new seals were installed from the pump, updated sct fitting, to the new manifolds, stand pipes and dummy plugs. Even the injectors are the Ford Reman’s.
Thank you for the clarification on the relay. I understood what you were instructing me to do, and I appreciate that. I was not aware Of the strain on the FICM by simply cranking it.
With icp unplugged the PID will read a default value. Reinstall the icp and crank for 10 seconds at a time, let the starter cool off and keep doing it for 4 or 5 cycles. If ICP never comes up I'd do an air test.

Sent from my SM-A505U using Tapatalk
Thank you for the reply, Waggonerj. Do you know of a way to purge the air that’s trapped inside the hpop system?
Will the air eventually work it’s way out of the system by turning the engine over or will the air stay trapped within the system until the components are removed and re-primed?
It will work it's way out as you crank it.

Sent from my SM-A505U using Tapatalk
big brains ? well that leaves me out
Take the ICP sensor out and crank over -- do you get oil flow?

Yeah, and I dont have a big brain either
Take the ICP sensor out and crank over -- do you get oil flow?

Yeah, and I dont have a big brain either
Even if you are meticulous, it is common to leave some lint or other foreign material in the high pressure oil system after a big repair job. If you have done that, it can accumulate on the IPR valve screen and prevent the necessary pressure from being obtained. You might want to pull that and check it of you see oil coming out of the ICP sensor port when cranking.
Even if you are meticulous, it is common to leave some lint or other foreign material in the high pressure oil system after a big repair job. If you have done that, it can accumulate on the IPR valve screen and prevent the necessary pressure from being obtained. You might want to pull that and check it of you see oil coming out of the ICP sensor port when cranking.
Gonna have to call you out on part of this post -- I am assuming you are referring to the screen on the tip of the IPR?

The IPR valve is a dump for the pump flow
Any restriction, lint or otherwise on the IPR screen will cause the pressure in the oil rails to be higher than commanded -- rather than lower

Restriction on the pump inlet screen(under the oil cooler) will have the opposite effect -- and starve the pump
It accumulates on the screen, the screen tears from the restriction (and the increased pressure drop across the screen), or the solids pass through the screen, and the valve sticks due to solids or screen material. I was lazy ........

The point is that trash in the system will cause low pressure in the HPOP system.
I agree that it’s possible for lint to be in the system, but to have enough to cause an oil flow issue? The engine ran for an entire year with molten plastic throughout the System, and ran pretty darn well. That’s one of the reasons I had to rebuild it.
The ipr valve is brand new, as is the screen in the valley.
There is no oil flow visible through the icp sensor port. I’ve been pushing oil into that manifold through the icp port. There is a ton of air in there.
I agree that it’s possible for lint to be in the system, but to have enough to cause an oil flow issue? The engine ran for an entire year with molten plastic throughout the System, and ran pretty darn well. That’s one of the reasons I had to rebuild it.
The ipr valve is brand new, as is the screen in the valley.
There is no oil flow visible through the icp sensor port. I’ve been pushing oil into that manifold through the icp port. There is a ton of air in there.
It has happened to quite a few folks. Do a search.

A stuck open IPR valve can cause your issues. You have described an amount of cranking that is beyond what you should have to do.
I understand what you’re saying. And I agree that I have been cranking this engine much longer that it should’ve taken, but there is zero run time on this engine.
with the icp sensor in, 1.5psi, ipr at 85%.
icp sensor out, or unplugged, 953psi, ipr at 42% I think? I think the valve is working.
I honestly think there’s a ton of air trapped within the system.
FWIW, when I put mine back together, I filled he oils rails prior to cranking. I took out the FICM relay and I'd guess I probably had a total of 30 seconds to a minute (10-15 second cranks) of cranking before the ICP came up. Installed the FICM relay and fired it up. It ran a little rough to start with, but cleaned up fairly soon.

I think you have a leak. Maybe a cut seal on installation or something.
It could possibly be an IPR issue like @bismic said too.
An air test sounds like a good idea at this point.

Just how fast is the oil filter canister filling up?
Did you fill the HPOP reservoir with oil before assembly?
You guys might be correct on the cut seal possibility.
The oil filter housing fills up within a couple of seconds of cranking.
I did not fill the reservoir before assembly but I did dump about a gallon of oil down the filter housing.
I do have FICM sync. FICM main power is at 48.5v.
1 - 20 of 27 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top