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Discussion Starter · #1 ·
I just rebuilt the motor in my truck and have about 350 miles on it. Included in the rebuild was a new t500 hpop and single shot injectors.

Truck runs great, starts fine, etc and torque shows about 3000 psi at 40% for icp at wot.

The last couple morning (two different times) it took for ever to start and I suspected the hpop had drained. Today before I started it I pulled the plug and it was basically bone dry.

It has started every time cold just fine other than these two times.

For the two times it would not start I had it backed into the driveway so it was on an incline (front lower than back).

Any ideas what it could be? It must have something to do with being parked on the hill. I was thinking drain valve. Could it be injector O rings? I just don't understand why the O rings would cause it to drain down when not running.....

Thanks.
 

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Ipr was rebuilt.....I guess there are two different style gaskets. Could that be it too?
The openings in the gasket are for inlet to the pump and outlet to the crankcase from the IPR discharge. If it's leaking between those, that could drain the reservoir.

There's a standpipe on the inlet from the quick-fill check ball, so it shouldn't drain down thru that.
 

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Discussion Starter · #5 ·
It it were the check valve how tall is the stand pipe. I was not able to see any oil and the dental pick I stuck down in the hole was about 4in long and dry.

I just parked it about 3 hours ago and went out and checked and it's already about 2in down.

I started the truck and rechecked and it's right at the top. I pulled the two hpop lines just to make sure it's not injector related.

If it's still low in the morning I'll probably check the gasket next.

Thanks!
 

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THe check ball is in the block, and removed you won't see oil in there. It drains all the way to the pan. Look for knicks and marking on the ball, it shouldn't have any. Most the time its either junk got in there, rare, the seat is worn out, replaceable for cheap, or the spring broke, comes in the kit with a new seat and ball. Just by chance, who built the motor, and who took the seat out and put it back in? Reason I ask is if they didn't remove the seat, then it probably got lost during cleaning and they never even knew it was there. In which case you won't see one in there and the spring will be useless and the ball won't seal right, but will seal alittle , enough to run after lots of cranking. The seat is the same on both sides if you replace it, so don't freak out wonding which way is which. lol.
 

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Discussion Starter · #7 ·
THe check ball is in the block, and removed you won't see oil in there. It drains all the way to the pan. Look for knicks and marking on the ball, it shouldn't have any. Most the time its either junk got in there, rare, the seat is worn out, replaceable for cheap, or the spring broke, comes in the kit with a new seat and ball. Just by chance, who built the motor, and who took the seat out and put it back in? Reason I ask is if they didn't remove the seat, then it probably got lost during cleaning and they never even knew it was there. In which case you won't see one in there and the spring will be useless and the ball won't seal right, but will seal alittle , enough to run after lots of cranking. The seat is the same on both sides if you replace it, so don't freak out wonding which way is which. lol.
I rebuilt the engine.

Seat and ball are there. Im not sure its going to be the check valve though, because like klhansen said (and from what I have read) if the check valve is bad it should not drain past the stand pipe. The reservoir looked totally dry. I dont know how tall the sandpipe is though so that could be an issue......

If I end up pulling the plug Ill change the seat and all. How is the seat removed? When I had the engine apart the seat was really in there.


I just find it odd that it has been sitting several times (for a few days) and never had a problem until it was on a grade.......weird.
 

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Not sure which vehicle you have, didn't see a signature. But my 02 had a different hpop gasket. There are two. Also, what kind of grade? Pick up tube crack? I think the test for that is to put as much oil in the pan as possible and jack up the back of the truck as high as you can get it. It then submerges were the pick up tube bolts on and the whole tube so if its cracked, it will work again being submerged.
 

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Discussion Starter · #9 ·
I pulled it apart and changed the gasket. It had the correct one in there but I got a new one anyway.

I did not replace the ball, looking at the resevior there is now way it could be all the way dry due to the stand pipe. I pulled out the valve and there was also oil standing on top of it so I'd guess it's fine.

Is there any way it could be injector O rings?
 

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Is it still draining down with the new gasket?

It wouldn't be injector O-rings. The oil would have to get thru the HPOP to leak out there. The pump tolerances is too close for it to drain thru the pump.
 

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Is it still draining down with the new gasket?

It wouldn't be injector O-rings. The oil would have to get thru the HPOP to leak out there. The pump tolerances is too close for it to drain thru the pump.
You would have to hot wire the IPR in order to get anything past the HPOP.
 

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Discussion Starter · #13 ·
Help!

I am at a loss, replaced injector O rings and still drains down after 3-4 days.

So far I have changed the cover to reservoir gasket, injector O rings, and pulled and cleaned the check ball.

What else can it be. I am about to go crazy.

Would I throw an ipr at it?
 

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Help!

I am at a loss, replaced injector O rings and still drains down after 3-4 days.

So far I have changed the cover to reservoir gasket, injector O rings, and pulled and cleaned the check ball.

What else can it be. I am about to go crazy.

Would I throw an ipr at it?
Were the injector cups cracked maybe? Or a crack in the front cover down low inside the reservoir? Would have to clean It up pretty good to look down In there. But I have heard of cracked front covers in several different places including a reservoir. But it leaked out, not in. Possible I guess. What about the two real tiny drain plugs for the rails under each cover. The two aluminum ones real small. My build manual told me to be real careful putting those back in as they will leak. Maybe??Don't know just tossing it out there.
 

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Discussion Starter · #15 ·
Thanks for the suggestions, I may pull the reservoir again and double check for any cracks.

The little plugs had new o rings during the rebuild and they were still in place when I pulled the valve cover (i was going to see if they were tight but totally forgot).

New injector cups at rebuild.


Back to the ipr, does anyone know for sure if oil can leak past it allow the reservoir to drain. I have never seen a subject with so much conflicting info.....

I found a ford tech bulletin saying the only way the reservoir to be dry is the gasket, or a porous reservior (reservoir did not leak prior to his) but I have seen posts where people claim their drain down was due to injector O rings or ipr......
 

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I can't see how it could be anything on the HP side of the HPOP. That includes the IPR, Injectors, or relief valve (the big hex plug on the passenger side of the HPOP). I say that because the oil would have to get from the low pressure side (reservoir) thru the close clearances of the HPOP pistons, then out thru a leak (or the open IPR port) back to the pan or valve cover.


With a standpipe in the inlet side of the reservoir, the oil can't drain down any farther than the top of the HPOP reservoir standpipe, and the quick fill check valve passage goes thru the standpipe as well.
I could drag out my spare front cover/reservoir and investigate further, but unfortunately, don't have time to drag it out of the shed.


In the meantime, here's a good resource for HPOP issues, although it doesn't address reservoir drain-downs. http://www.thedieselstop.com/faq/9497faq/download/HighPressurePumpSupplementDiagnostics.pdf
 

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Thanks for the suggestions, I may pull the reservoir again and double check for any cracks.

The little plugs had new o rings during the rebuild and they were still in place when I pulled the valve cover (i was going to see if they were tight but totally forgot).

New injector cups at rebuild.


Back to the ipr, does anyone know for sure if oil can leak past it allow the reservoir to drain. I have never seen a subject with so much conflicting info.....

I found a ford tech bulletin saying the only way the reservoir to be dry is the gasket, or a porous reservior (reservoir did not leak prior to his) but I have seen posts where people claim their drain down was due to injector O rings or ipr......
I don't really know the answer to the IPR question, but I would assume that since the minimum starting pressure is 500psi, and everyones high pressure system is at zero when they start there truck. No ones truck holds pressure. Then I would think the IPR is wide open until it gets to 500ish, then the magnet fires up and restricts it to what the PCM wants from there. If not, I would think if you had a electric wire fail on the IPR and tried to start your truck the IPR would be shut and the pump would lock up from pressure since it can't pass the IPR. So it must be open just for common sense and safety. But I have no Idea. Sorry.
 

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The IPR is basically a relief valve, and with the key off, the IPR is fully open, and drains out the HP oil (to zero pressure) into the pan thru the port in the front cover. On key on, the PCM controls the IPR to 14% closed, which is enough to bump the pressure up to 500 psi for starting. When the injectors demand more oil, the PCM increases the duty cycle of the IPR signal up to a maximum of 65%.
But since the IPR is on the high pressure side of the pump, it can't drain the reservoir without something else going wrong within the HPOP.
 

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The IPR is basically a relief valve, and with the key off, the IPR is fully open, and drains out the HP oil (to zero pressure) into the pan thru the port in the front cover. On key on, the PCM controls the IPR to 14% closed, which is enough to bump the pressure up to 500 psi for starting. When the injectors demand more oil, the PCM increases the duty cycle of the IPR signal up to a maximum of 65%.
But since the IPR is on the high pressure side of the pump, it can't drain the reservoir without something else going wrong within the HPOP.
Wow! So my reasoning was right for once. Cool!
 
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