7.3 fuel pressure regulator issues - Diesel Forum

ToddT · 03-31-2006, 07:48 PM

Last night my truck felt like it had clogged a fuel filter. I checked my vac/boost gauge and it was fine. Temps good. Plenty of fuel. I switched back to diesel and it died. Back to WVO and it limped home. Parked for the night, I switched back to diesel and let it idle quite a while. It was still running rough, just like low fuel pressure. When I turned over the key I could hear the fuel pump working.

This morning I checked the fuel bowl without draining it and found the fuel level down equal to the pressure regulator/fuel return outlet. Hmm... that doesn't seem right. There should be no air in the fuel filter housing, right? The fuel filter looks fine.

I noticed what looks like rubber sticking out from the fuel return line where it bolts into the pressure regulator. Sure enough, those o-rings are shot.

As one who works with chemicals, I don't see anything in WVO that could cause this type disintegration. They aren't swollen like from using a solvent or anything.

Has anyone else had problems with the o-rings in the factory pressure regulator? By the way, the local dealership didn't have one in stock. Their price would have been $78 plus tax and any expedited freight bills. I ordered it from www.thepowerstrokeshop.com and their price was $58. Even with the more expensive Saturday UPS shipping it will still cost within $2 of the local dealer. Plus, they had it in stock and shipped it out today.

Hopefully that is all that's wrong with my truck. Any ideas?

Todd

longroundtip · 04-09-2006, 08:25 PM

That's odd, I thought Ford started putting Viton seals and O-rings in all of the fuel system components around '99 or even earlier... Unless this is non-biodiesel related and just physically damaged. How many miles do you have on biodiesel? Describe the O-ring; is it crushed, cut, torn, mushy, soggy, hard, cracked, stretched or any other adjective that I missed? In my experience, biodiesel will either soften a plastic to the point it "melts" or make it so hard it's brittle. Right now I'm thinking it was caused by the regulator not seating properly, or some debris got caught between the regualtor and the oring when the regulator was open and damaged it. Or I could be thinking of the wrong seal altogether.

ToddT · 04-09-2006, 10:11 PM

The o-ring damage looked more like the material was torn, not softened or swollen from solvent reaction. I've only used a little biodiesel but hundreds (thousands?) of gallons of heated WVO.

I'm thinking the damage is from dirty fuel as the fuel return exits the filter housing before it is filtered.

I agree that some debris seems to have gotten in the spring/seat of the pressure regulator. New spring and seat... no problems since.

Todd