hey guys I'm Steve, i work on a lot of 6.0's here for my buddies. i am a previous diesel mechanic and have done multiple 6.0 motor swaps and complete rebuilds. I'm having 2 issues with 2 different trucks!!

Truck 1
truck was a no start cold, if you run it and shut it off it would restart fine. if the truck sits for more than 4 hours or so, it will crank a very long time. everything is fine except the icp pressure. when the truck sits its like its losing its prime.
when the truck cranks long after sitting i have LOW ICP pressure.
i tore into it, air tested and a stand pipe and hpop where leaking. replaced all the leaks i could find with air testing and it still is doing the same thing!!

Truck 2
a buddy uses a f550 for hauling a car trailer, last year he got some diesel and drove the truck 10 miles and it died. they towed it to a shop and they could not get the truck started. it sat for 8 months then was towed to me. i charged the batteries and it fired right up! after running for a few minutes it was clear that the egr cooler or head gaskets were leaking(white smoke from exhaust) so i replaced and tested the egr cooler(bad) and re sealed the housing due to a bad oil leak. i also replaced the HPOP because the ipr had metal in it and the screens where all blown in the oil cooler valley. finished all this and now THE ISSSUE: truck runs fine idling but if i tap the pedal it revs really fast and hangs the rpm's for a second or two (very scary!) and will begin to idle very poorly. fcim, icp and hpop all in check.

ANY HELP GUYS!! these are not your typical issues

 

Truck # 1: It seems to me if you found 1 stand pipe leak, the others (other stand pipe and both dummy plugs) might also be leaking. Did you air test again after replacing the stand pipe and HPOP?

Truck #2: Did you replace the ipr? If you did, did you re-check for metal in the ipr? I wonder if the IPR can get stuck...has anyone ever seen one get stuck?

 

truck 1, no air leaks after the repelled hpop and stand pipe. but when i am air testing I'm getting air out of the pump right above the seal. there is a drain hole for the ipr? has anybody seen this before?

truck 2 no i did not recheck for any metal. the valley for the oil cooler was clean so I'm thinking the metal was defiantly from the hpop. i replaced the hpop and screen swell as the stc fitting.

 

Having the ECM reflashed at Ford to the newest calibration really helps a lot of running staring and drivability problems. I would start there on both of them. Its possible that even though the FICM has 48v that the logic or brain side is bad and faulty. I have had that happen a time or two. Its also possible that somebody swapped a ficm in that is not the correct programing for the pickup. So again I would have the ecm and ficm reflashed to latest calibration.