1971 F250 Aux fuel tank

[Karl]

I am trying to get my Auxiliary tank under the bed to work. The valve that switches tanks works and fuel comes out but I can't get the fuel to the engine. Doe this tank have a fuel pump inside? I haven't been able to find any data on this tank. Any help will be appreciated. Thanks

[DGrant09]

Our tank is gravity fed through the tank selector valve next to the drivers seat. If the fuel is passing through the selector correctly but not reaching the pump - I'm stumped. Does it run on the cab tank and what is the condition of the fuel lines? Our selector switch and lines look pretty rough (surprised it works) and I hope to replace soon. I'm sure after 30+ years they're corroded inside..

One issue I had when I first owned the truck was I was not turning the selector far enough and of course the truck would run outta gas..

[DGrant09]

Hey, BTW - Welcome to the site!!

[FORDification]

No, there's no fuel pump in the auxiliary tank. It's just set up with a float and pickup tube just like the in-cab tank.

I agree with DGrant09, I think I'd first check the fuel lines to make sure they're not clogged. If they appeared OK, then I might double-check the selector switch to make sure it's not clogged. If the lines are good and the selector valve not clogged, it should be good to go, if the truck will run off the in-cab tank.

[sideoilerfe]

Make sure the valve is in the correct position. On my 72, It has a 3 position valve. However, only two tanks. I found out the hard way that the middle position was OFF. In other words, I wasn't putting the valve in the correct position.

[Karl]

Thanks for the info. I guess I will have to drop the tank. I put new fuel lines in from the tank to the selector valve and some gas came out so I just figured the lines were clear. I know the selector switch works. The inside tank works fine but at 11 miles to the gallon I have to fill up every 3rd day. When i get a chance to drop the tank and find the problem i will post it.

[FORDification]

You might consider blowing some compressed air back through the lines to the tank, to free up anything that might have gotten it clogged. (It might save you from having to drop the whole tank.)

Was the tank being used when you got it? If not, had it been setting long? It's possible there's some rust in the tank that's coming loose and clogging the pickup tube. There's a sock on the end of the pickup tube that might be clogged up. Here's a shot of the sending units for that tank, just for the visual: