problems running the front tank on a dual tank 97 F250 HD
I have changed the fuel pump in the front tank twice. I don't believe the fuel pump itself is the problem. Just after putting the pump in I started the truck and it ran fine. After shutting it off and it sitting for a couple of hours it wouldn't start. Switched to the rear tank and it fired up. Drove down the road and switched back to the front tank, it took about 10 seconds and the front pump started working. Now the front tank doesn't work. I can hear the fuel pump running when the key is on but no fuel to the engine. The relay has been changed, the 20 amp fuse is fine. There is no fuel selector valve that I can see on this truck. I've followed the fuel lines and they do not go to any box or valve. They go to the top of the back of the engine.
remove fuel hose at the fuel tank selector switch and see if pump is working, it may be the switch that is not allowing flow from front tank to engine, if not, remove front fuel pump and inspect hoses for pin holes or loose fittings within the tank
I can't find any tank selector switch other than the switch that is on the dash from front tank to rear tank. All the hoses are fine and no pinholes or leaks of any kind.
There has to be a selector valve that has 3 hoses attached to it, o from each tank and one to the engine. look behind the seat or under the cab by tanks
I have found 2 lines that go to the top of the back of the engine. One line goes through the huge in-line filter and the other just runs up to near the fuel pressure regulator. I traced the fuel lines of both tanks and don't see anything that looks like the selector valve at all. All the fuel lines can be traced to their respective tanks.4 to the rear and 4 to the front....supply and return and 2 vacuum lines each. I appreciate your patience with this but I'm seriously at a loss. I have a repair manual for this truck but it doesn't show where it is. There is nothing on the left frame rail nor under the cab.
Check on drivers side frame rail just about half way down
I did. It's all fuel lines. The only big thing is the in-line filter and that's near the front tank.
I have searched every inch of this truck and do not see anything remotely close to the selector valve. I also have pics of the entire area.
Hey I hope I can maybe help you, watch this you be video; YouTube 1987 F150 dual fuel tank selector Repair. https://youtu.be/qBE3LWWmelM
This thread is kind of old but the reason you cant find one is because there isn't one. Ford stop using it in the 90s each pump has its own check valve and the only selector is the switch on the dash. Problem could be in the switch itself or a bad wire connection.
I'm having these problems also. replaced pump and moving on to wires and the switch. If you fixed yours, what did you find?
I traced the 2 supply lines to what looked like a single little block of metal...the check valve maybe? It would have to be cut out and replaced with another one or an electric switching valve would have to be put in it's place. If you can follow the supply line from the huge in- line filter mounted to the frame rail back to the point it splits into 2 lines that should be the check valve.
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