Is it the HPOP???

[justinlogue5_0]

I have been working with another guy on another forum and we think we know the problem but I wanted some extra opinions on this problem. The truck is my E99 with 293K factory everything (to my knowledge) on the motor except for the hpop but I will get into that later. When cold/cool the truck will start fine and run fine (for a factory 7.3). Once it gets hot/operating temperature it feels weak and at a WOT or even under a slight empty pull up a hill the check engine light comes on saying bad/incorrect ICP. I put a manual gage into the oil rail on the head to watch pressures. When running normal it will hit 3000 to 3200 psi but when it acts up it will get kind of stuck around 1900 to 2000 psi untill you start to let out of it and then it will jump to 3000 psi and then fall back down to where it needs to be since your letting off the throttle. Then the real problem is when you shut it off. While hot (or even couple hours later while still hot) it takes over 20 to 30 seconds to crank. While its turning over you can watch the gage buikld to 350 to 400 pretty quick but then hesitates to get to the 500 psi it takes to fire off the injectors.

Things I have done ...
New oil change
new ICP
Swapped out IPR with know good one
new fuel filter(old one was still clean)
Contrubution and buzz test good
blow by a minimum amount.

No smoke ever noticed while driving(except for a small quick black puff when first floored)

Ok wise and holy PSN people, help me out. Thanks.

PS-HPOP is a new rebuild hpop from a known source/company that I won't mention at this time. I contacted him and he swore up and down I have other issues and there is no way it is his pump giving me the problem.

[7.3]

well he cant know that it isnt his pump making the problem... everything can fail. it looks to me like its the hpop. how long have you have this one in and it worked good?

[justinlogue5_0]

Well that's the "Well duhhh" thing about this hole deal. I thought the factory 15* cranked to long but after comparing it to other 7.3' s it was pretty normal. After I put this 17* pump in, it started almost immediately not working right. I thought it was just still trapped air but after a while and a lot of hard runs I knew it wasn't air. I also checked for oil aireated oil. All looks good. Have only had this pump in for 3000 miles now. I am gonna try and find a low mile used or new rebuilt 17* and get this one out. I think I am just wanted everyone else to re-confirm what I believe to already know.

[golfer]

injector poppet valves leaking HPOil

http://www.swampsdiesel.com/files/7....Diagnostic.pdf

[justinlogue5_0]

Thanks Golfer but as I read that article (which is very good by the way) the last paragraph on page 1 all the symptoms it talks about are backward from what I have. All my problems are when hot not when its cold.

[golfer]

I probably need to edit that document...but when oil gets hot it thins out...and the (poppet) valves are now leaking more volume than the pump can produce...whichis why IPR% skyrockets...pressure drops and then the truck dies...until the oil cools off/thickens up...

The 6L document (on our FAQ page) describes this same scenario...hot oil..stalling..no restart until the oil thickens up...but on the 6L trucks...the issue is usually all the BS fitting/tubes/o-rings etc inbetween the HPOP and the injs..

7.3L trucks have their HPOPsystem 'external' to the engine...

hell..get the truck hot...pull the valve covers...and then if you're pretty sure it won't restart...crank the engine and LOOK at how much oil is pissing out the top of each injector (where the spool valve is)...

the fact is that the pump is making good pressure...pumps are rarely intermittent...the tolerances inside the HPOP are very precise in order to produce that kind of pressure...and the fact that the pump CAN make pressure at all...means that the pump is (with 99.999% certainty) not the problem...

if your injs had half the mileage they have...then we'd go somewhere else..like the IPR...which you did without any change...

if you want, rig up a way to individually pressurize each cylinder head with the pump/IPR out of the loop..and see how much oil escapes the inj poppets...

[adrenalinejunky81]

Did you actually bleed the air out of the heads at the plugs or are you assuming its all out? Ever reseal your injectors? It doesn't sound like the pump to me.

[justinlogue5_0]

Originally Posted by golfer

I probably need to edit that document...but when oil gets hot it thins out...and the (poppet) valves are now leaking more volume than the pump can produce...whichis why IPR% skyrockets...pressure drops and then the truck dies...until the oil cools off/thickens up...

The 6L document (on our FAQ page) describes this same scenario...hot oil..stalling..no restart until the oil thickens up...but on the 6L trucks...the issue is usually all the BS fitting/tubes/o-rings etc inbetween the HPOP and the injs..

7.3L trucks have their HPOPsystem 'external' to the engine...

hell..get the truck hot...pull the valve covers...and then if you're pretty sure it won't restart...crank the engine and LOOK at how much oil is pissing out the top of each injector (where the spool valve is)...

the fact is that the pump is making good pressure...pumps are rarely intermittent...thew tolerances inside the HPOP are very precise in order to produce that kind of pressure...and the fact that the pump CAN make pressure at all...means that the pump is (with 99.999% certainty) not the problem...

if your injs had half the mileage they have...then we'd go somewhere else..like the IPR...which you did without any change...

if you want, rig up a way to individually pressurize each cylinder head with the pump/IPR out of the loop..and see how much oil escapes the inj poppets...

Oh ok,that makes since now. Now that I think about it I remember reading somewhere where a guy did just that and new which injectors was actualy bad if not all of them. When it cools down a little(106* right now) I will pull the covers off and see what's going on. Thanks man!

[TerminatorEngineering]

If the pump is one of mine, I'll take care of it. But I think Golfer has you on the right track.

[justinlogue5_0]

I am saving back some money for Stage I's and a 6 pos chip anyways.Hopefully that will cure all my issues (with the truck anyways,). It makes since that the factory tired poppit valves just couldn't take it anymore when I went to a new higher pressure pump. Thanks Golfer!