Intermittent high pressure oil problem

JoshH

JoshH

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Apr 2, 2007
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I'm working on a truck that is driving me crazy. It has an intermittent problem holding high pressure oil. It is very easy to make it happen, but I can't figure out what is causing it. Here's what I have. It's a late 2004 F350. If you are driving below 60 mph, it does just fine, but if you try to get it out on the highway running 70, ICP pressure will start dropping out sporadically. If you keep trying to drive at that speed once it starts this, it will eventually die. It will start again after it dies, but it takes a lot of cranking. Otherwise, it has no problems starting either cold or hot, as long as it doesn't die. Does anyone have any idea about what is going on?
 
If you go from 0-60 hard pull to the floor does it hit and maintain the desired 4,000 psi at all? Could be a IPR sticking but can it make the full 4000psi at WOT?
 
It will command a max of about 3800 and it holds it just fine until it starts acting up. IPR valve % is right around 75 when it runs good. When it starts acting up, it will go to 85% and ICP drops to nothing. I thought it might be an IPR valve problem, and I put a new one from Motorcraft on it. It still does the same thing.

One weird thing it does I forgot to mention, if you hold it to the floor, it will stop pulling at about 3100 RPM. It just kind of sits there not doing anything, but if you let out a little, it will shift and take off again. ICP is right on what it is commanding and fuel pressure doesn't drop below 45 PSI when it does this.
 
IPR is at 75%?? Are you talking about when you floor it or just driving normal? I'd be curious as to what the lpop is doing at higher RPM's. There's not much on the hpo side that relates to rpm.
 
04 powerstroke said:
Low pressure gauge doesn't ever drop does it?
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No, it stays right in the middle.
texans said:
IPR is at 75%?? Are you talking about when you floor it or just driving normal? I'd be curious as to what the lpop is doing at higher RPM's. There's not much on the hpo side that relates to rpm.
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Sorry, that post wasn't very clear. When it's running right, it goes to 75% to get 3800 psi when it's to the floor. When it acts up, it goes to 85% just cruising.
 
So just cruising it's running 85%? Trying to help you out and make sure my info is correct. Is this 85% only while problems persist or all the time. 85% is the max the PCM can command. If it's going that high the PCM is doing everything it can to try and keep up with the demand on the hpo system. If that's the case you have a hpo leak somewhere or a weak hpop. You should only be running mid 20% while cruising. Just for grins pull the oil filter out and hold down the drain back. Have someone crank on the motor by either the yellow/green wire by the battery or with the key (ficm relay needs to be out for this) and see how long it takes to fill oil filter housing with oil.
 
Ever had the oil cooler replaced? Dorman one maybe?

How did the old IPR look when you took it out? Specifically the screen.

Does it have a new updated fitting on the (late) pump, or the early pump?

Next time it happens, unplug the ICP sensor to rule it out, and make sure the connector is not full of oil.

My gut says you have the beginnings of a hpo leak. The ipr numbers you are giving us are all too high for everything to be right.


Owner @ Power Automotive. ASE Master, L1, T2. Pretty much a Cummins fan, but I fix them all 50+ hours a week.
 
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