j_fire

On my 1993 f150 XLT i have a problem that seems very common when I fill both tanks up after driving it for a little it fills on mine mainly the rear tank to the point it over flows. now i did a little research and it seems that the fuel pressure regulator allows to high of pressure that it damages the check values in the fuel pumps. now I'm gonna replace the regulator but i need a little help on how to test check the fuel pumps check values with out dropping the tanks. please let me know if this has happen to you and how you fixed it.

Just call me Sean

iTrader: (1)

The tank is overflowing, that means the check valve is bad.

j_fire

can i replace just the little pump or do i have to replace the whole assembly?

Nitehawkjr

You can replace just the pump, or the module, without replacing the sending unit. Just make sure that you replace the strainer also

Just call me Sean

iTrader: (1)

The whole assembly.

Cowboywrench

I may be just being lazy about this, but my truck does the same thing. If I fill both tanks and run on the rear one, it overfills the front one. If I run on the front one, it runs out normally. Self curing problem in my book. I run on the front one until it is low, then switch to the rear. After it is down to 1/8th a tank, I run the front again. Actually, my front tank doesn't like to be filled from the neck, for some unknown reason, so I typically just fill the rear one. I can fill it twice before switching to the front one. MPG is curious to determine this way, but my truck likes gas too much to want to know just how bad it is anyway. With 32's on, my speedo is off some too. At best guess, I think I am getting around 14mpg, so it is within normal ranges.
If time or money is tight, I'd try this rotation method until you find enough motivation or other reasons to start digging into the system. If not, then there you go. I'd follow Sean's advice and change out that part.