Thanks Adam. Man I guess it's a possibility. I sure as heck hope not. That means engine pull. I have had the valve covers off and it was really clean under there. Hopefully the rest of the mill is the same.

 

If the psi goes up to 50 then I would doubt the pickup screen is clogged. Also if it starts then how could the rails be clogged? I think pulling the cooler first is the right move but what do I know?

 

You have a good point Glenn. I have a newer oil cooler coming from a 97. Apparently according to the wisdom of Travis, the check valves in the newer builds have a C-clip that hold them in. In my build, it's just staked in there, if that makes sense. I'll spend the next day or so REALLY cleaning up under there. It's been leaking for awhile. This has been a PITA, but it feels good to be doing it right. This poor truck was just neglected.

 

I have a small update. Read the link below. I stumbled on it when trying to find new check valves and if they are even available.

Some one school me on the Short Circuit Valve. - PowerStrokeNation : Ford Powerstroke Diesel Forum

I am not a member on that forum, but the article kinda blew me away. He was experiencing the EXACT same problem I am currently.

So, the positive....I understand the oiling system better than I ever have. I am not gonna lie...it has been pretty daunting to go through this because I had NO idea what the problem could be, especially after installing a Melling LPOP. I am still not 100% sure until I install the new oil cooler tomorrow and try to get him started and STAYING running. But now,I really understand the system thoroughly, high pressure and low pressure side. I could pass a final exam on it LOL!!!!

I will have a verdict tomorrow when I see if it will stay running. If not, then off comes the HPOP and the short circuit valve to the standpipe. That is the only part that hasn't been taken apart and examined yet. I am tempted to do it now while I am waiting, but I want to know 100% for sure what the issue was. If I address both at the same time, I won't know for sure. Here is what I do know:

1) I have zero cranking pressure
2) Truck fires and goes to 50 (normal) then slowly falls off and dies
3) The res is way down after this happens...not 100%, but more than half way
4) If I refill, I can repeat this all day long
5) Final verdict...res is not filling so its running out of oil and low pressure

Now, I also hate to admit this, but I checked the oil level yesterday and it only had a drop on the dipstick!!!! The first thing I checked when I parked it was the oil level and it was full...but, it has been parked nose down on an incline for two weeks, and pretty steep incline at that. I'll get that figured out as well when the oil cooler goes on tomorrow and I get it buttoned up. I only drove it about 75 miles since doing the E-Fuel and resealing the HPOP, so it should not have gone anywhere.

Anyways, that's where I am at. Thanks for following along. More tomorrow. Hopefully the check valve in the new cooler solves this issue, but if not, on to the short circuit valve.

 

I looked at the article but what is a short circuit valve? Is it the ball bearing?

 

I figured I'd chime in with some info that's hopefully somewhat relevant.

Your current truck is a 95 right? If so, the anti-drainback valve for the HPOP reservoir should be on the HPOP itself. In 96, they switched to having that either in the front cover or the block. I know this because my Bronco was suffering from losing oil in the HPOP reservoir after shutting it off, and I discovered a later model HPOP was put on. I don't think this would be your issue though, because my truck ran fine when it did finally start.

I think you mentioned it but another thing to check is there should be some type of valve in the oil filter housing (the rear end of the oil cooler underneath the oil filter). I believe there is a c-clip and plate with a spring visible when you take the oil filter off. I don't remember exactly what this valve does, but I think it does have to do with pressure. Maybe it fell out during an oil change or the clip came loose and is causing your problems? I read it is somewhat common for these valves to come out on the OBS 7.3s. I know mine did on the piece of crap motor I pulled from the donor truck and it caused some problems as well. I had to buy a whole "new" oil cooler from a super duty so I could get that valve back because the missing parts were long gone when I discovered the issue... man I bought so many parts for that motor. At least I have a bunch of new things for my replacement I have to clean up!

Also, I assume you looked at the LPOP cover o-ring when taking it off recently right? When I first resealed my motor, I thought the o-ring under the LPOP looked too small and shrunk since it was semi loose in the groove. Not knowing any better, I threw it out and replaced it with the super thick looking gasket/o-ring that came in this seal kit I bought. Needless to say, it was way too thick and caused a gap from the LPOP housing the the front cover and I couldn't build oil pressure.




One last thing. I'd hate to think it's something along these lines but since you mentioned your oil seems very low, maybe there is a possibility the oil is being used faster than the LPOP can supply it? I would think you'd notice some other issues if this was the case. Also, since you said your LPOP pressure is at 50 then falls off, it seems unlikely this is the case. Maybe something to look into after checking everything else. To me, I'm thinking it's something with one of those valves or maybe an IPR getting stuck? I don't know too much about the IPR yet, but I think it can cause oil issues and has some valve in it.

 

Glenn, it's the check valve for the standpipe underneath the HPOP that sits in the block. All it is is a spring that sits on a 1/2" ball bearing.



Lemme know if that doesn't make sense.

 

I may be wrong on this, but I'm pretty sure the short circuit device is what changed in 96 from the 94.5 to 95 motors. I don't believe 95 and older powerstrokes have this, they are present on the HPOP itself.

 

Man I really appreciate the input. You may not know, but in the thread I posted before this I covered most of what you brought up. I thought HPOP drainback at first, but res stays full overnight and truck won't stay runnning for more than 20 seconds after it starts. It dies and stutters as low pressure falls off. I have pretty much narrowed it down to the low pressure system. I have a '97 cooler coming tomorrow with low mileage check valves. There are two in the cooler and one in the block. It's one of those three or silicone debris stuck in the short circuit valve. That what I have narrowed it down to with my diagnostics so far.

The good news is the inside of the block that I can see is REALLY clean. I'll have more information in the morning after installing the cooler. The LPOP and the seal are brand new.

I'll definitely look into possible oil loss once it is running reliably. It has never used oil since I have owned it. Even on the drive home from Texas, oil level stayed full. I don't think it's an issue, but at this point, with this truck, anything is possible.

 

I found this from an older thread that explains the valve a little bit. From reading it, I know that the short circuit device is what was changed in 96. 95s and older had this in the HPOP like I was saying. I don't believe it would cause your truck to stall if it was running though.

 

I just thought of something if you haven't checked it out yet (you probably have so this may seem dumb.)

You say your oil seemed low right? Maybe it's possible you somehow are very low on oil that when the truck is running, you actually run out of oil to pump up to the reservoir? Have you tried filling the truck up with a bit of oil? Maybe drain the oil into a clean container to check how much is in there, then fill it back up.

I know my truck stalled out on me about 2 months ago on my way to work. I managed to get it back home and it was started and stalled a bit. I drained the oil and had like 5 quarts in the pan! This is when I realized how much fuel was diluted in my oil. I re-hooked up my CCV, and because of how I hooked it up with the combination of how thing my oil was, it sucked up and burned most of my oil! When I filled my truck back up with oil, everything seemed fine again! I disconnected the CCV and it didn't suck oil back up anymore. However, my oil leaks started getting worse due to the thinning of the oil. I doubt you have the fuel dilution issue I have, but maybe you are loosing oil some other way like injector o-rings or something.

Edit: Actually reading the explanation from that diagram I quoted from DIYMechanic: "If the oil filter bypass valve malfunctions and lets the oil gallery drain, the engine will start and run for about fifteen to twenty seconds before reservoir runs out of oil, then the engine will spin awhile to burp the air out of the gallery and refill the reservoir, then the engine will restart."

That sounds awfully similar to what you're experiencing! Maybe that new oil cooler you have on the way will fix it! I'd still check the oil level though if you haven't!

 

That valve is in all of the 7.3s from my understanding. I found the Allen head but haven't pulled it yet. It's there best I can tell.

I can't verify the true oil level until I get it off the 8 percent grade it's parked on LOL! I know it was full or close to it when the problem arose.

 

Here's the check valve in question

 

take a peek at this thread too for the low pressure issue, wonder if the regulator valve is sticking open/hung up since symptoms seem the same
https://www.ford-trucks.com/forums/1...placement.html

 

Adam, thanks for posting those. It made it more clear.

Alright, update:

I got him started and staying running! How you ask? By putting in 2 gallons of f****** oil! Good God Almighty am I an idiot. I did the oil cooler job and got it all back together. I kept it running long enough to make sure it was ok and then I moved it up my driveway to a flat spot so that I could verify the oil level. Yeah, it took another 3 quarts to get it full. My man card has officially been revoked. I just thought the way it shut down so sudden, after running so well, that it was something else. It may have been the check valve in the cooler. It did seem like it was hanging up, but I cleaned it really well with carb cleaner and then soaked it in oil for two days while I did everything else. It moved very freely before I put it back in, so I went with it.

The next question. Where in tarnation did 3 gallons of oil go in 50 miles of driving? See below...



Looks like I have an injector oring issue...a big one. I am going to button it up in the morning and take it on a long hard drive to get all of the air out. I am also going to carry 4 extra gallons with me and check it every 15 miles or so and see how it's doing. I just want to make sure. I have AAA, so whatever happens will happen. It runs like crap right now due to all of the air in the system. I don't want to just guess on why it's losing oil, so this is my next step. It passes a rev test although it sounds like crap.

So, it runs and has a full crankcase. Seems I don't have to mess with the short circuit valve for now...thankfully. More tomorrow. Again, thanks for all your help guys. I am out of the woods, but not fully home just yet.