Fuel Problem in '85 Ram

[Roy_T]

Can anyone help with this problem? I'm almost out of things to look at. I have an '85 Power Ram 150 4WD with automatic transmission and 318 engine. It conked out on the highway behaving as if it had run out of fuel. The gage was showing 1/4 tank. We towed it home and checked the lines and they seemed to be clear. We blew air back into the tank and it pressurized slightly, and fuel dripped out of the line. We tried an old fuel pump from a previously running engine, but when you crank it over still no fuel pumping from the outlet of the fuel pump. We tried a brand new fuel pump with same results.
One might think at this time that maybe there was something in the tank covering the outlet (we did) but we were able to drain the tank easily by siphoning from the line.
Another possibility we thought of was the cam lobe for the fuel pump, but the engine was overhauled about 4,000 miles ago and the cam was inspected and appeared satisfactory with no unusual wear at that time. We did run a little low on oil twice, but a much more experienced mechanic said that couldn't possibly account for that much wear. It did seem as though we were getting really poor mileage the last couple of tankfuls, but I'm not sure, and I don't see the connection. The onset was sudden, with no tapering off of performance as one would expect if it were wear on the camshaft.
I don't know what to check next.

[BleedDodge]

What I would do first is keep that new fuel pump on, and connect a short hose to the fuel tank side (the draw side) and dip the hose in a pail of gas. Turn the motor over and see if the fuel pump will pump fuel to the carb side. If it pumps fuel, you know there's something messed up with the tank or the lines. If it doesn't pump fuel, you know there's something messed up with the fuel pump drive. It can't get much simpler than that...

[pind]

check any and all soft lines ( hoses ) on the intake side of the pump, including those on the top of the tank, it is quite possible that in a negative pressure situation, such as when the pump is drawing fuel, the lines have deteriorated to the point of allowing air leaks. Or, more maddening yet, they have deteriorated inside, and when the pump is drawing fuel, there is a flap of rubber inside the hose that closes off the line, so that the pump cannot draw.

The final, and possible worst case scenario, is that there is something wrong with the pickup tube, within the tank, that is allowing the system to draw air. This does not sound too likely, as you say you can siphon from the fuel line.

Also, if there is a filter on the inlet side of the pump, make sure it's clean

Good luck, keep us posted.