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1994.5 - 1997 7.3L Power Stroke Diesel  

An Engine Rebuild/Refresh Thread

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Old Dec 5, 2014 | 07:20 AM
  #196  
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...crap. i was fearing that myself. and yes, the LPOP was on.

a few more bits of info that may or may not matter. Its a Melling LPOP which is rated for higher flow (so maybe primes less well?) also, it came with a new housing since its a slightly different geometry and i jsut took it out of the box and put it on the engine, following their directions to not re-arrange anything and not force the gears over the driveshaft if they're not aligned right. so, i can't really see how i would have screwed something up with it...

also, its a relatively old starter on there. it always started the truck before the tear down, but it always felt slow.

i think my plan will be to fix up my SD starter (the solenoid contactor went bad) and try spinning it with that. then, try putting the GPs in and getting wired up for running shape. then, fill the HPOP to the brim and try starting like that.

i know the damage that Nick did to his front cover from a backwards LPOP, but i've probably done all the damage i'll do and if it aint gonna pick up oil, its can't send those chips anywhere...

can anyone out there say for sure that you can start an engine with a bone dry HPOP reservoir, though? and if so how much cranking would you anticipate? minutes? tens of minutes?

thanks guys.

this sucks, but i'm still hoping its nothing in the end (fingers crossed)
 
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Old Dec 5, 2014 | 08:19 AM
  #197  
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The Melling M208 has less gear teeth on the rotors as opposed to the OEM pump. According to Melling, this allows for greater volume at equal psi. According the the OEM there is "damper" stamped onto the side that goes toward the damper, according to melling, it's universal, so if you didn't force it, it's on there right.

Is there a way to fab in a gauge pre HPOP to see if you are getting LPO to the HPOP?

Is the HPOP reservoir filling with oil or is it draining back?
 
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Old Dec 5, 2014 | 08:41 AM
  #198  
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Why not fill the hpop and oil filter to the top before cranking? The hpop still has to fill the heads so it can start.
 
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Old Dec 5, 2014 | 08:59 AM
  #199  
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I feel for you JP. It's a heart sinking feeling. Hopefully it's nothing
 
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Old Dec 5, 2014 | 09:14 AM
  #200  
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Originally Posted by ProjectDually
The Melling M208 has less gear teeth on the rotors as opposed to the OEM pump. According to Melling, this allows for greater volume at equal psi. According the the OEM there is "damper" stamped onto the side that goes toward the damper, according to melling, it's universal, so if you didn't force it, it's on there right.

Is there a way to fab in a gauge pre HPOP to see if you are getting LPO to the HPOP?

Is the HPOP reservoir filling with oil or is it draining back?
Good info, thank. So yes it has to be on right.

And no the hpop is not filling at all. Actually there is no oil flowing at all. At least not to the oil filter. I filled it 3/4 before cranking and it's still at that level....
 
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Old Dec 5, 2014 | 09:18 AM
  #201  
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Originally Posted by oldbird1965
Why not fill the hpop and oil filter to the top before cranking? The hpop still has to fill the heads so it can start.
Good point. It can't hurt anyway. And once the heads are full of oil (which may take a few fill/crank cycles, maybe) the hpop should stay full...

At that point I might as well give a try starting it up and hoping the faster loop spinning picks up the new, thick oil better...

Here's to lots of hoping!
 
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Old Dec 5, 2014 | 09:37 AM
  #202  
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ok, i feel better. i'm pretty sure this thread covers my problem and a few potential solutions.

priming a melling m208 - PowerStrokeArmy

i know i followed the install directions to a tee (which was easy since they were so simple), but there should have been a note to use grease or something thicker than oil if you won't be starting the engine right away. unbeknownst to me at the time, i have a feeling that the "soaking in oil" part of the install is key to priming, but only really works if you'll be restarting the engine soon after install. considering i've waited, oh, about 4 MONTHS after install and flipped the engine countless time in between, i bet its bone dry in there.

seems as though if i can get some oil down onto the pump somehow i should be in business pretty quickly. with no fender in the way, pulling the oil cooler (for the 3rd time since rebuild) may be the best options. worst case i pull the damper and reinstall the pump again - slathered in oil or grease this time!
 
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Old Dec 5, 2014 | 09:41 AM
  #203  
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Originally Posted by OldWoodsDiesel
ok, i feel better. i'm pretty sure this thread covers my problem and a few potential solutions.

priming a melling m208 - PowerStrokeArmy

i know i followed the install directions to a tee (which was easy since they were so simple), but there should have been a note to use grease or something thicker than oil if you won't be starting the engine right away. unbeknownst to me at the time, i have a feeling that the "soaking in oil" part of the install is key to priming, but only really works if you'll be restarting the engine soon after install. considering i've waited, oh, about 4 MONTHS after install and flipped the engine countless time in between, i bet its bone dry in there.

seems as though if i can get some oil down onto the pump somehow i should be in business pretty quickly. with no fender in the way, pulling the oil cooler (for the 3rd time since rebuild) may be the best options. worst case i pull the damper and reinstall the pump again - slathered in oil or grease this time!
I am sure hoping this all that it is. After reading it myself, it seems that is key to priming/getting it started. Rock on!
 
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Old Dec 5, 2014 | 10:40 AM
  #204  
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Originally Posted by OldWoodsDiesel
Good info, thank. So yes it has to be on right.

And no the hpop is not filling at all. Actually there is no oil flowing at all. At least not to the oil filter. I filled it 3/4 before cranking and it's still at that level....
Glad it helped, and good luck!
 
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Old Dec 5, 2014 | 12:39 PM
  #205  
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Yeah, you'll definitely have to fill the HPOP reservoir if you want to start it. And it will only run for a few seconds without LPOP pressure because the engine running will drain the HPOP res as the injectors pop off (the oil returns to the crankcase). If you're reasonably confident that the LPOP is on there right, and it sounds like you are, I'd say fill up the HPOP res and give it a go. You'll likely have to take several turns cranking it since it's really bone dry. If you want to eliminate some of the cranking take off the small plug in the HPO rail on the passenger side and the ICP in the driver side and fill the rails with oil through those holes. If you do that and fill the reservoir, I wouldn't be surprised if it would pop off and run in the first couple 30 second turns. 30 seconds of cranking then at least 5 minutes to let the starter cool. Keep the batteries on the charger while you're doing this too to keep the charge topped off. I think you'll get it going pretty quick here. If you get it to run and it runs a few seconds and then dies (like Nick's motor did), then I'd say you need to look at the LPO system and see what's going on.
 
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Old Dec 5, 2014 | 12:44 PM
  #206  
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I remember TJ saying that the PCM will shut down the motor if it senses low or no oil pressure. How does that play into starting a rebuilt motor?
 
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Old Dec 5, 2014 | 12:53 PM
  #207  
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Originally Posted by oldbird1965
I remember TJ saying that the PCM will shut down the motor if it senses low or no oil pressure. How does that play into starting a rebuilt motor?
I didn't realize our trucks had a LPO sensor. I thought that was only for HPO?
 
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Old Dec 5, 2014 | 01:27 PM
  #208  
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Originally Posted by ProjectDually
I didn't realize our trucks had a LPO sensor. I thought that was only for HPO?
The lp oil pressure sensor is on top of the hpop reservoir. Confusing, but that reservoir sits at low oil pressure and supplies the hp pump.

And that plan makes sense Nate. I may still try bathing the lpop in oil again somehow and cranking as is just to be sure it's ok though.
 
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Old Dec 5, 2014 | 01:40 PM
  #209  
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Garden sprayer with oil plumbed to oil pressure switch port.prelubes the whole thing.
 
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Old Dec 5, 2014 | 01:44 PM
  #210  
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Originally Posted by OldWoodsDiesel
The lp oil pressure sensor is on top of the hpop reservoir. Confusing, but that reservoir sits at low oil pressure and supplies the hp pump.

And that plan makes sense Nate. I may still try bathing the lpop in oil again somehow and cranking as is just to be sure it's ok though.
So if you had the right fitting, you could put a pressure gauge in the reservoir fill port to check LPO?
 
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