Cool thanks for the help. Now to decide if Ill pull the bed off again or drop the tank. I have a new pump on the way. Ill get that installed and get a gauge on it right after.

Probably rig up a pulley system on the roof of my shop this time to pull the bed.

 

Glad you guys are out there. I can do the work but can't always diagnose the problem. Damn scandalous shops saying " we'll have to replace the whole fuel system " . Money hungry jerks.

 

This is all interesting reading. Thought I do that as I'm contemplating buying an '89 F150. To me it isn't overkill to replace both tanks and fuel pumps and now I learned from this, an '89 has a selector valve, that will be replaced too. All the above I call preventive maintenance. From Missouri, its going to Arizona this fall, don't need no problems en route.

 

hoss73ford,

Note that this thread was for the fuel system found on 1990 and newer Ford Trucks.

The 1989 had a low pressure pump in each tank and a selector valve mounted on the frame and it was pressure operated by the low pressure pumps in the tanks.
Any filling of the non selected tank was a problem of the selector valve on the frame.
Non switching of the tanks when the tank selector was switched the problem was either a bad selector switch or a bad non running tank pump.