Ok, I'm a little confused how the dual fuel tank set-up works on my 95 F250 5.8L. I spent about 1/2hr. under the truck tryin to trace the wiring and supply lines.
I ran my fuel pressure gauge off the shrader valve and got the following values.

Front tank: Key on, pressure to 10psi, off, then back on, 15psi, off then back on, 20psi, started and running, 25psi, revved, pressure drops to 20psi

Rear tank: Key on, pressure to 30psi,started and running, 30psi, revved, pressure raised up to 35psi

Now I'm wondering if a fuel filter or bad connection could be the culprit before I go and frop the tank and spend big money on a new in-tank pump.

Can someone explain how the lines are run, where the filters and the selector between the tanks are? I keep seeing two high pressure lines, one with some grey covering and the other with blue???

Thanks!

 

Unfortunately it sounds like a front tank fuel pump issue if the pressure is not 38 to 45 psig. Before doing anything else, check the fuel pressure regulator. When going bad they will cause some quirky issues. It doesn't appear that the FPR would be the culprit though if the front tank only has the low pressure readings.

 

The fuel goes like this:

Tank -> selector valve -> filter -> fuel rail -> return line -> tank

If one tank has lower pressure than the other, then the in-tank pump needs to be replaced. Ford fuel pumps die like that, slowly. Mine did, and I just replaced both while I had everything off (I did mine from the top).

 

sounds right to me is there room to do that from the top? it looks like maybe on a one ton but close?

 

OK, so it does sound like it's the front tank in-tank pump. I looked at removing the bed and going from the top. How easy is this? I see about six big bolts that go right through the bed into the frame. What is the torque spec on these?

I did pull the vac line from the top f the reg. and there was no fuel in it so it should be good. I'll change the filter while I'm at it too.

 

Removing the bed is easy depending on how much rust there is. On a very rusty vehicle, you're going to run into problems no matter which way you go. To take the bed off, you have to disconnect the fuel filler hoses, disconnect the rear wiring harness for the brakes and signals, and unbolt those six bolts you're talking about. It will lift right off. Not sure what the torque spec is, but the tighter the better. Also consider putting some lock washers in there if there aren't any already. I doubt you can overtighten them.

Your FPR is probably good, based on the fuel pressure you posted. Changing the filter is always a good idea.