[cRaZy8]

Ok, so I have been chasing a "ghost" for long time now. About 2 years.
It almost seemed intermittent at times. Now, I can turn it on like a switch.

These were some other threads with similar issues, or my threads:
http://www.powerstroke.org/forum/6-0-trannie-problems/261950-4th-5th-converter-lock-bucking-slipping.html
http://www.powerstroke.org/forum/6-0-motor-problems/263506-bucking-hesitation-missing.html
http://www.powerstroke.org/forum/6-0-motor-problems/213427-6-0-missing-during-acceleration.html
http://www.powerstroke.org/forum/general-6-0l-discussion/260488-6-0l-bucking-losing-hpop-5th-tcl.html

Truck was bucking on the highway, in 5th, with TC locked.
Passes all injector tests, hot or cold. Never throws a code.

Here are my symptoms & facts:

-only on the highway
-noticeable on flat ground, but more so on a hill/incline
-only happens with slight throttle input (20-50% throttle, roughly)
-only after trans is up to 140* or higher
-only in 4th with lockup, and 5th with lockup (via Edge Insight)
-truck lunges/bucks/shakes with slight throttle application
-smash the throttle and it screams, no issues
-if you hold the throttle just to maintain speed (or decrease speed as you inclince), it wont do it
-much more noticeable with my boat in tow, higher load on engine/trans (boat, trailer, gear weighs about 5k)
-no codes
-all engine parameters stay solid during the bucking
-FICM 50V+
-RPM does not flicker
-ICP voltage solid
-HPOP psi steady
-Fuel pressure never drops below 59psi, usually steady at 61-63*
-ECT never above 195*, 205* max towing
-EOT never above 195*, 202-203* max towing
-Both near 189* while around town

Recent maintenance or upgrades since the issue started-

-Trans fluid drained around 75k (91k on clock now), new pan gasket, filter, and TP filter, Mercon SP, fluid level dead nuts in the middle the "H" when around 160*
-8 new injectors
-new frame mounted fuel pump
-BPD 53V FICM, 6phase unit
-BPD tested Logic board FICM
-IDP FICM tuner
-FICM wiring harness
-Shell T5 Rotella
-Shell Rotella ELC
-Fuel filters every 5k miles
-Front & Rear diff fluid changes
-Transfer case fluid change
-New HG's (Black Onyx failure)
-ARP's
-New OEM Ford turbo (not a rebuilt)
-IDP long Y-pipe (EGR delete pipe)
-Riffraff Diesel intercooler boots


So, the newest problem surfaced today.
I always keep an eye on my Edge while driving, and today I noticed my HPOP psi was not building as high as usual.
Went for a quick blast up a side street, she wouldnt build more than 1600psi.
I remember seeing 3000+ on a WOT blast.
It seems to be sticking around 1400-1600 under heavy throttle.

My only question is, is it possible the IPR is stuck, not allowing the pressure out of the pump?

Either way, I am at 93k miles, I think I am replacing the HPOP and IPR now any ways.

 

[Tuscany]

Your ipr closes to allow the pressure to build up. Once the desired pressure is built than it opens.

 

[cRaZy8]

So my best guess is the IPR is stuck or sticking.

I just got back a Blackstone Report last week from my last oil change.
My wear was near zero, and they said the oil sample looked great.
Besides the potassium levels (Rev-X), all was good.

 

[Tuscany]

If your hpo is only building to 1600psi max the you are probably experiencing a failing hpop. Are you getting this reading on stock tune or is the truck tuned? If it's tuned than that will skew your readings.

 

[cRaZy8]

This is on a tune.
But just last week I can recall seeing 3000+ psi while tuned.

 

[my0460]

Could it be the dummy plugs bad?


Sent from my iPhone using AG Free

 

[cRaZy8]

Not likely. I replaced them this past Feb, and the problem was there before and after that.

 

[tburns00]

I have also been chasing the same problem for the last year and a half. I have done everything i can think of short of dumping gas in the S.O:B and setting it ablaze. I just wish i could find what it is and be done with it before i rip out the powerstroke and put a cummins in it.