Hi, Every time I get stumped I post on here! Lol. I bought a 97 Ford F250 4x4 XL regular cab a week ago, it quit running on the guy, he knows nothing about engines, and only used the truck to put his boat in the various lakes around his area, he said they put a new fuel pump in it. ( I checked, it looks new) . I jumped it with my truck, I let it charge for about a 1/2 hour first, then when I tried to start it, the "WTS" light worked (you could see the glow plug solenoid was new too) The tach was working, and it wouldn't even try to start, so... I checked all the pertinent fuses, and changed out the IDM relay with the horn relay, just to be safe, and plugged the IPS sensor on the driver side head (don't know why it was unplugged) and tried again, .............still nothing. I have a hose I made years ago to pressurize fuel tanks. I deal with antique cars a lot too, and I pressurized the rear tank, which the switch was set to, and had a friend crank it....NOTHING ! I took the inlet line off the fuel pump, and pressurized the tank, plenty of fuel, I took the outlet fuel line loose after tightening the inlet line, cranked the engine, no fuel, the strange thing is, there is fuel in the fuel bowl, I opened the drain valve, and it came running out of the hose. Then I put a fuel pressure gauge on the schrader valve, and it just barely moves it when it is cranking, I guess it is enough to fill the fuel bowl, but not enough to make it run? Anyone ever hear of the lobe that runs the fuel pump wearing out? Also, the "CEL" is on while cranking, and I put a code reader on it, no stored, or pending codes, the truck has 332K miles on it, it is a 5 speed. And it IS FOR SALE !! Lol

 

Check the spring on the FPR. If it's broke you won't have fuel pressure

 

Thanks Mike, I'll check that tomorrow Wish me luck! Lol

 

I was going to check the regulator spring, then I remembered, I'm not pumping any pressure directly out of the pump itself, before it even gets to the regulator.....I took the filter out of the bowl, then drained the bowl, I cranked the truck over by the solenoid, and after about 6 times of cranking, for about 20 seconds each time (batteries were low, I was jumping it off my truck) the bowl filled up enough that when I put the filter back in, it overflowed, still won't even try to start even with the bowl full, which I expected that it was full before, I suspect this is a pressure issue, not enough fuel pressure getting to the injectors. Do the cam lobes for the fuel pumps have a habit of wearing out on these after a lot of miles?

 

No it's not a common problem but can happen. If the bowl is filling then the pump is being pumped. The pumps can fail and out fuel in the bowl but not pump it out.

 

By that you mean, the pump may be weak, but still have enough pressure to fill the bowl, but not be strong enough to pump the fuel out of the bowl?

 

The mechanical pump has two stages. The first stage is to put fuel in the bowl at maybe 5 psi. The second stage is to get fuel from the bowl and pressurize it to maybe 50 psi. Could it be the second stage is not working?

 

How do you check the second stage? I see a banjo bolt fitting at the rear of the pump, it has two steel lines going from it, one to each cylinder head, to feed the injector rails. And I see what looks like a rubber hose going from the front of the pump, and I can't see where it goes from there, I see it goes somewhere under the fuel bowl though.

 

As mentioned before check the pressure regulator spring. It's easy to do, the large bolt on drivers side of fuel bowl. Once the bolt is removed you will see a spring. Make sure it is there and not damaged. If it is damaged or missing you will never build high pressure, all the fuel will just return to the tank.

Here is a thread I made diceting the mechanical fuel pump. That should answer most of your questions. Good luck ...

https://www.ford-trucks.com/forums/1...l#post16159003

 

Awesome, will be checking it today

 

I took the spring out of the pressure regulator, there is no screen that I can see. I can see the port fully exposed where the fuel transfers from this park over to the outlet fuel line side. Is this a plunger that is fully depressed and is not supposed to be?

 

The spring fits inside a piston. The piston is removable and you can use a magnetic screwdriver to remove it. On reassembly put the piston in, install the spring then the nut so the tit on the nut is inside the spring. Did you have all those parts?

 

Here is a picture of the piston/plunger spring and bolt. Scroll down to the bottom ...

TikiWiki : Shim Your Fuel Pressure Regulator 94-97

 

I have all those parts except for the screen, it is mmissing, I cranked the engine over with the piston out, it pumps fuel freely through there, there is no real pressure behind it to speak of, but I understand that is normal.

 

Well, I put it all back together, took the regulator off and checked the screen, looks squeaky clean, if I crank the engine over with either of the rubber lines cracked loose, that go from the regulator to the front of each cylinder head, I do get fuel. It does not seem to be very much pressure, just runs out in a stream while the engine is cranking, I cracked the nut loose on the line going to the back of the driver side cylinder head that feeds directly from the back of the fuel pump, and I got no fuel at all while cranking the engine. I did speak with the previous owner, and he said the truck was running after the new fuel pump was put in for a while, but then one day it just would not start, all he did at that point was try a set of new glow plugs, which obviously did not do the trick.