95 F250 Powerstroke. Always started right up but blew white smoke for a few minutes. Today no start, not even close. ICP cranking is only 220ish psi and duty cycle is exactly 50.0%. Injector oring? How can I determine which one? Ill re oring the 4 on whichever side is bad, and do the other 4 when I have more time. If in fact it is an oring.
No start-low icp
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You can block the heads off one at a time and see if you are able to build ICP. Once you find the side of your leak you should re-connect that bank and preform a visual. It could be a poppet stuck open if there is trash on the oil.
Have you tried swapping IPR's?
Have you tried swapping IPR's?
davey99ps
New member
I've got a spare hpop you can use if that ends being the problem that came out of my 95
I may take you up on that if needed. Thanks. But can't see how an hpop could fail overnight. Is 50% duty cycle max while cranking? Is that all the pcm will allow?
Are there different ipr's between obs and superduty? I think my spare is out of a 17* pump.
vapstroke
New member
see if it will start with the icp sensor unplugged.
Did that. Same no start.
davey99ps
New member
Ipr's are the same I believe, but the 94.5 and 95 hpops have an anti-drain back valve in them. So if you put a newer pump on an leave the truck sit for a few days, the resivoir will bleed down. Atleast that's what i was told when i went to upgrade mine.
vapstroke
New member
Check the hpop reservoir if it is full of oil you most likely have a stuck ipr valve.
Reservoir full to the top.
Removed the ipr and no oil came out. Removed the plug on reservoir and it is full. What is up with that? Thought it was supposed to drain the reservoir?
EDIT-It is draining, just slowly. Down about an inch and quarter in 15 minutes.
EDIT-It is draining, just slowly. Down about an inch and quarter in 15 minutes.
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Also, before I removed the ipr, I capped each fitting at the pump. With passenger bank blocked, icp was 165 ish cranking. With driver side fitting fitting blocked, still no attempt to fire, and I know these things will run on one bank of cylinders. Couldn't record icp because no sensor in that bank and the wiring wouldn't reach anyways.
I can splice in another pigtail for passenger bank if anyone thinks it will help.
Took the ipr apart and it was real clean. I don't think anything is wrong with the ipr. Another check valve clogged somewhere? The reservoir slowly draining with ipr removed has to have something to do with it? Something blocking above the non serviceable plug?
I did replace the non serviceable plug with one of guzzles longer ones. I got the check ball installed correctly and it ran great for about 150 or so miles. Not like that ball could fall out with the plug/pin in there.
Edit again-Can the icp sensor be bad and make the ipr do what its doing? Its dry unplugged. Guessing not because it should default to something unplugged, correct?
I can splice in another pigtail for passenger bank if anyone thinks it will help.
Took the ipr apart and it was real clean. I don't think anything is wrong with the ipr. Another check valve clogged somewhere? The reservoir slowly draining with ipr removed has to have something to do with it? Something blocking above the non serviceable plug?
I did replace the non serviceable plug with one of guzzles longer ones. I got the check ball installed correctly and it ran great for about 150 or so miles. Not like that ball could fall out with the plug/pin in there.
Edit again-Can the icp sensor be bad and make the ipr do what its doing? Its dry unplugged. Guessing not because it should default to something unplugged, correct?
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BigAlsPSD
New member
Usually at that pressure you have an IPR that is hung open, generally only registers 180-250 psi, did you try pushing on the needle to see if it feels good?
The 95 hpops dont have an edge filter in the pump. It is in the ipr, which is why I don't think you can use a newer ipr on the older pump.
Hmmm....good question. The tiny needle should move in and out in the pilot valve? Can I test it assembled or do I need to take it apart again? I never tested it, but did spray it out real good with brake cleaner. So if it wasn't before, it may be now. The piston moves freely.
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Took the cap thingamajig off the end of the ipr and pushed in the pilot valve and it did move in and out smoothly. Put the ipr back in and cranking psi was about 2200 and it even fired for a second with no fuel bowl. Put it all back together, smoked and knocked for a while, and now its running great!
So I am guessing the ipr was indeed stuck open when I initially took it apart. Glad it decided to crap out when it did. I was going to pick up a fifth wheel trailer when it decided not to start. I am going to drive it for a bit before I go pick it up.
So I am guessing the ipr was indeed stuck open when I initially took it apart. Glad it decided to crap out when it did. I was going to pick up a fifth wheel trailer when it decided not to start. I am going to drive it for a bit before I go pick it up.
Charles
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Fwiw, on the duty cycle thing, that 50% isn't actually meaning that the valve is 50% closed. It means that the pulse width modulation signal is 50% on and 50% off, which actually correlates with roughly full valve closure and then some. Anything past the 40's really is pretty well fully closed. High 30's even.
All that number means is that 50% of the signal time, the signal is active, in this case grounded. That is plenty of duration to suck the IPR all the way closed. Any more than that would just saturate things and overheat the thing without helping anything.
All that number means is that 50% of the signal time, the signal is active, in this case grounded. That is plenty of duration to suck the IPR all the way closed. Any more than that would just saturate things and overheat the thing without helping anything.
Gotcha, thanks!
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