This is probably a no-brainer but my Fuel Filter Light came on within a few miles after switching to my rear tank. The engine didn't die but grumbled a lot. Went back to front tank and light went off and engine settled down. My truck has been sitting a few weeks with the rear tank full. My first thought was water in the fuel, but I thought the light would have been "Water in Fuel" I believe I have such a light. (1993 F250, 7.3 IDI). Fuel filter is fairly new. If it is water, what can I put in the tank to absorb it? thanks

 

Try switching again a few times, most likely the tank switch didnt fully switch over the rear and cut off the fuel partially, which would create a vacuum between the filter and IP which triggers the FF light. You are right, if water in the filter the WIF light will come on, assuming its working.

 

I'll give it a try today. Thanks

 

The fuel filter light has gone off, apparently for good However there appears for to still have a fuel issue. Once switched to the rear tank I can now continue down the road for awhile. But after a mile or so, holding steady at approx. 60mph, the tach starts down a little, power falls off. It acts like the engine is not receiving enough fuel. goes back to smooth running when switched back to front tank. I replaced the plastic fuel pick up cone in the front tank - it was in tiny pieces. Does the rear tank have the same cone? I was thinking maybe I've got something restricting he fuel intake. Any ideas?

 

the fuel filter light comes on when the fuel isn't being pulled up.the water in fuel is different and means just that.so she's probably sucking air from a rusted out fuel line,a failing selector valve or yes,pieces of the plastic pick up screen blocking the fuel.might need to drop the tank to find the issue.

 

thanks ford250hdxlt. does the rear tank have the plastic cone intake? if so I'll order one to have on hand when tank is dropped and inspected.

 

Yes, the rear tank has the same strainer (showerhead) on the pickup as the front. But if the rear tank is full, it should still draw down to about 1/4. Unless some broken part of the pickup has been pulled into the line and lodged somewhere.

 

Thanks. I got a new cone and will have it installed Monday. I'm guessing obstruction now because as I continue to run the rear tank the engine will slowly slow down until it dies at that point the fuel filter light comes on. I'm thinking the old cone may have disintegrated as the front one had done except the rear one sucked a piece of it into the intake.

 

carfully inspect fuel lines and vent

 

Thanks speedwrench72. I would have forgotten for sure. As it turns out the fuel line and vent were ok but the plastic intake strainer cone had disintegrated. The same as happened on my front tank in December. I thought then I should go ahead and check the rear tank, but didn't. but now both tanks have new intake strainers so I guess the clock is running on these new units. I'll mark my calendar to check them in another 22 years. Thanks all for your help.