Here is a pic on PHOTOBUCKET of my HPOP. The line closest to the front of the motor blew completely out of the housing, pulling the threads right with it.....any ideas on how this happened? What causes way too much pressure? or do these things just fatigue over time?

When she blew, I was not pulling anything, just climbing a short gradual grade....nothing serious at all....

2000 F250, no mods other than the napa air filter and doorman uppies. I do burn veg. oil in it, but have never had any fuel related issues until now. I think I probably have about 50,000 miles with veg. oil. The truck has 175,000 miles on it now. IMAG0267_zps61e7ac74.jpg Photo by bike_guy123 | Photobucket

In the pic, aluminum threads are on top, fitting with some of the threads still on it and of course, the stripped out hole!

thank you advance for help......comments welcome too.

MIKE in SPAMTOWN MN

 

If it pulled the threads out like it looks, you are going to need a new hpop. I would get a Terminator T500 HPOP and new hpop lines and you should be good. I'm not sure yours would be good for a core or not. I dont think a repair is possable without replacement. i could be wrong. Expensive day unfortunately. Good luck

 

Yup, I know how much and have done research after my first post a few days ago on choice.....

anybody know what may have caused this?

 

Yup. I sure do. The most typical cause is being in it and the HPOP isn't delivering the goods. The problem can be a tune with an excessive pulsewidth, low fuel pressure/air in fuel, or a weak HPOP. After enough time of digging a hole under your throttle to get more power, then you suddenly let up - the Powertrain Control Module (PCM) is caught off-guard... sleeping on the "more oil" switch. Technically, the Injector Pressure Regulator (IPR) was being told to raise the oil pressure, because the Injector Control Pressure (ICP) was so low. As soon as you fall off the throttle, the demand is just shut off, and the oil pressure spikes crazy high with the IPR wide open. This can be called the HPOP "H" remover maneuver.

Here is a very tame example of what happens (5000 PSI spikes are not unheard of):

 

Also, It may have been over tightened at one point pulling and stretching the threads inside the Hpop because of a small o-ring leak . over time the metal just gave up and let the line fitting blow out with the threads. That would be the best and the obvious reason..

When things start to leak everyone seems to think tightening the fitting will fix it. they never check the o-ring to see if it's bad causing the real reason for the leak.
Don't ask me how i know...

 

If it were mine, I would install a timesert. This would be after I turned the o-ring face into the timesert in the lathe, Drill and thread the pump, insert timesert with locktite and set the pins. Install and wait till the next day to start so the loctite can set up.

But also after thinking about it quick I would also be tempted to make up an over size fitting, ream the pump hole, tap new threads, install over size fitting with new o-ring and loctite, and be on my way.

 

That fixes the symptom, then it's a matter of finding the root cause.

 

I am sure it was most likely fatigue. Those lines and fittings get shaken not only from the motor but from the fluid pressure pulses inside the lines. I would more likely expect the line to fail way before the fitting pulling the threads out from overpressure. But this is all speculation without readings. What is the most pressure a HPOP can put out if it were allowed to run wide open against a dead wall?

 

Overtightening is the most likely cause.
The pump has an internal valve designed to release excess pressure in the event that occurs. The discharge port for the blow off valve is in the front cover, behind the the drive gear.

 

X2 on what Greg said.