I have a 99 F450. I was driving home yesterday and the truck sputtered and died. The gauge said I have 1/4 tank but I was sitting on a hill so I thought that it may be out of fuel. I had my fuel pressure gauge with me so I checked and I had no fuel pressure. I added fuel and tried to get it going but I had no luck. I tried putting compresser air into the filler neck and sealing it with a rag to help push the fuel through the lines, again no luck. I haven't had the truck very long but it's been plagued with fuel issues. I thought that maybe the mixer valve in the tank was plugged so I dropped the tank and checked and it was good. I did the "hutch mod" while I had it out.

The truck was running like crap a couple months ago and I went though the whole fuel system and everything seemed good. I swapped the fuel pump from my F250 at that time and nothing changed. I built and installed a regulated fuel system like Quikordead built at the same time.

Anyway, my queston is this: if the system is primed and the fuel pump running there should be pressure in the system unless A) the pump is spinning but is screwed and not making any pressure B) the pressure regulator is stuck open C) there is a plugged line somewhere. Before I go buy a new pump I want to make sure I have all the bases covered. Anything else?

 

I cnat see it being anything other than what you have listed. I would check the regulator first ford has had problem with them.

 

Does the return fuel come from the back of the head on each side?

 

no, the return is on the front of the head because it is higher than the back so in theory, the air should be at the front. Thats why I'm scratching my head, with the returns on the heads, it shouldn't take as long to prime the system as it would with the stock dead end fuel rails. For some reason I just can't get fuel up there.

I'm headed back out now. I'll be disconnecting the fuel line from the tank and adding a hose to the input side of the pump and trying to draw fuel from a gerry can. If that doesn't work, I'll disconnect the output hose and see if the pump is actually working. Those two steps should eliminate the possiblity of a plugged fuel line before or after the pump. If there's no fuel after that, I know it's the pump!

 

I unhooked the input line on the pump and connected a section of rubber hose. The other end of the hose was in a bottle of diesel. With the pump running there was no fuel being sucked out of the bottle. I thought maybe the line was plugged after the pump so I disconnected the output line and tried the pump again. There was a few little drops of fuel coming out and that was it. I guess we know it's the pump now!

When a pump runs but makes no pressure, whats the deal? The impeller wheel not connected to the armature on the motor anymore? Just a bad seal? It seems odd because it sounds like it's running fine, it's not loud, it doesn't sound like it has a bad bearing or anything. It sounds fine, it just doens't pump anymore!

I ordered a new one, it will be here tomorrow morning. Hopefully that's the whole problem!

 

freak,

You sure took it all to the limits finding your problem, and I can't see anything you didn't do to make sure it was really the pump. If you come back here tomorrow and tell us otherwise, I'll be REALLY surprised. You did everything I would have, AND MORE!!

Good job! A bonus is having the Hutch mod now!

Pop

 

Yeah, I had to be sure! If it was a $50 part I would have just bought it but I hate buying expensive stuff just to find out that isn't the issue. I was having electrically issues a while back and couldn't sort it out and everyone kept saying it was the GEM so after a week of searching for the problem, I bought new GEM (not returnable) and it didn't fix the problem. Now I have a slightly used GEM module sitting here that I may need later but I'm guessing not and I'll have a hell of a time selling it. My garage is full of parts that I got by jumping the gun!

 

You did the little oriface thing like I did? What did you do for the actual oriface fitting? I've been wondering about where to buy the supplies needed to make the thing other than cobbling idle jets from old carburators.

 

Oh, and my fuel pump just got replaced as well!

 

Hey guys, I got my new pump installed and it fired right up! Getting the system primed is a lot faster with the return lines on the head! Cycled the key twice and away I went! I think the last time I primed the truck (before the returns) it took me an hour or so and it involved compressed air and an other vehicle with booster cables to keep batteries up! That mod is worth doing just for the ease of priming alone!

Kwik, I went with the low buck, low tech solution! I took a piece of steel brake line, flared the ends for use with inverted flare fittings and I flattened the middle of the tube in the vice. This piece of tubing was then put inline between the "T" from the two heads and original return line. It works great! The space left after crushing it is so small that you can barely blow through it but it has no problem letting the air in the system out! It's kind redneck but it works. I spent a ton of time trying to figure out how to make an orifice small enough and I finally gave up!

 

freak,

Flattening the tubing is just quality "good ol' boy engineering" there! You may want to keep an eye on it for stress cracks for a while, though.

After the diagnosis you went through to determine it was the pump, somehow, I KNEW that you had come to the correct conclusion.

Did you check your old pump's inlet for the "crud" that Kwik shook out of his? See his other post about his VW pump substitution.

Pop

 

Ingenuity at it's best. Necessity is the mother of invention.
Getting rid of the air in the system sure does a number on the cackle don't it?

 

Well I was hoping that the new fuel pump would fix my no power problem
low boost thread but it didn't I'm getting tried of looking for this problem!

 

Remember that the injector fuel rails should be running around 70 psi, even at full power. Weren't yours about ten pounds less?

Maybe you need to shim up the pressure regulator a bit.

Pop

 

With this new pump I'm sitting at about 75psi. This truck is just a dog! It's brutal. Some mentioned that the IPC or the oil temp sensor may be out of spec. I'll have to check those out.