So I recently noticed a problem with my 2000 f350. I pulled a 8k load down to Houston and when going up a hill I noticed my icp was dropping and ipr opening more until it maxed out and icp was down to 1800. As soon as I let out of the throttle just a scootch the icp shot up to over 3200 psi. No codes, no cell, truck has almost 300k but starts fine hot or cold never has died on me and pulls like an ox. When the icp drops I can hear what sounds like the waist gate opening and the truck almost falls on its face but just as soon as the throttle is backed out its right back to normal. Also the oil pressure gauge never drops nor does the oil light come on. Eot is around 215 at the most.

I would suspect a sluggish or sticking regulator maybe...

What were those IPR readings? (and keep in mind that, in an attempt to raise the ICP, the PCM would be Closing the IPR not opening it). And of course, those % numbers are what the PCM is commanding the IPR to do Not what it's actually doing (there's no feedback from the IPR so, if stuck, those changes may not be taking effect).

They're expensive so you might try taking it out and clean/inspect it first or, if there's any possibility it's the original, try a new one (you'd have gotten your monies worth out of the first one )

https://dieseliq.com/how-rebuild-ipr...-stroke-diesel

Ipr is commanded to %65 I ordered a new ipr along with a melling lpop and high pressure hoses just for poops and laughs.

%65 ipr 1800 icp

E=65percent not sure why it's doing that.

Also at idle icp fluctuates. 475to500

Again, the IPR may not actually going to 65% if bad though. What it means is that the PCM is unsatisfied with the ICP pressure and is trying to make more by maxing-out the IPR percentage of closed (bleeding-off as little as possible).

IF it still does that with the new one then, you have other problems because you can be pretty sure it's really going to that 65%...

Your new pump and IPR should clear up the issue. The only other issue there could be is a leaking injector o ring, but if the truck starts up good hot then that’s not likely

You should be set with your new parts.


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Thanks it was the IPR valve and I had a leaky injector seal