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air test HPO system.....dead HPOP

3K views 11 replies 4 participants last post by  wrench-head 
#1 ·
When I pressurize the HPO system at the top of the j-tube with shop air, I get tons of air thru the pump and discharging from the HPOP intake (reservior). Does this mean my HPOP is shot? I got to this point because the truck died one day and will not start. Won't build more than 250 psi (AE monitored). Prior to this it had starting issues where it would fire, run for a second and die. Then after 2-3 times extended cranking it would run (rough). No power until warmed up. Probably multiple issues working here......but I want to at least get it running again so I can sort out the lack of power and rough running (injectors.....stiction.....etc). Thanks guys.
 
#4 ·
Pump is junk. Remove that discharge tube from the branch tubes and blow compressed air into branch tubes and listen for leaks. That will tell you if anything else is leaking. Also, probably don't wanna hear this but if your blowing air through the top of the discharge tube and pump and you hear air coming from the oil filter stand pipe, there is a chance that you have damaged or dislodged the oval mesh screen that sits below the oil cooler.
 
#5 ·
Kinda what I thought. The oil cooler/filter/etc component is already out as well as the screen. I am getting oil and air blasting out of the HPOP intake tube below the oval screen. Quite the mess. Previously I removed the j-tube and put air to the rest of the system to check. Thought I heard a bit of a leak in the left head area, but didn't seem to be from the rail or injectors. Was deeper than that. Pulled the hose to the rail and standpipe to look at o-rings. The standpipe was bent for some odd reason. Replaced that and it seems quiet now or no leaks on that side. Now it's just the HPOP leaking. Thank you for your input and quick response, dhanna6powerstroke. I appreciate it.
 
#6 ·
No problem. Also, if you're into it that deep you might have a couple other parts you should replace. Inspect the top of that discharge tube for any scratching or scarring. If you see any, inspect the HPOP cover for damage in the same area as the tube sits. If ANY damage is noted, it is suggested to replace the pump cover with an air updated unit. The new one comes with a new IPR valve installed. Also replace the discharge tube regardless of damage or not. I have the part numbers for the parts you need.
 
#7 ·
I did notice a little scarring or rub marks on the tube (below the seal). Didn't look that close at the cover. I've already got a new IPR and ICP sensor with pigtails/wiring because I was that far back and didn't want to have to go back in. Good suggestion on the tube and cover. If you have the numbers handy, please send them my way. Thanks again.
 
#11 ·
are you sure about the ipr pigtail? i've never heard of an updated unit. and that part# just shows me a regular ipr pigtail
 
#12 ·
update on the repair: new HPOP, pump discharge j-tube, left side standpipe, ICP sensor and pigtail, IPR and pigtail. fired up for a second after some cranking and died. found new codes for crank and cam sensors. weird. also noticed very very low injection control pressure. turns out one of the harnesses into the FICM wasn't quite right or all the way in. taking care of that fixed the CMP and CKP sensor issues. pulled the left valve cover (again) and saw the connection at the standpipe to the hose had come lose. put that back on properly. a little cranking again and it fired right up and runs like a champ. starts great now too. many thanks to all that posted replys. what a great site.
 
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