Dual tanks question, truck dies when switching
 

I have a 1992 F150 with dual tanks, the problem I have is when I switch to the front tank the engine dies, switching back to the rear tank it fires back up. I have seen a few different reponses to this topic on here. Does anyone have first hand experience as to what the problem really is? Any help will be greatful.

Tim

will it run at all on the front tank?? you probably have a bad fuel pump in front tank and it needs to be replaced. either that or your switch isn't working properly and it's shutting off the back tank without turning on the front.

no it wont fire up on the front tank, when I drive down the road and switch to the front tank the engine quits instantly, I flip the switch to the rear tank and it fires right up again. could it be a bad fuel pump relay?

it's possibly a bad fuse or relay, i would use a test light and see if you are getting power to the pump on front tank. if it's getting power and not working then it's the pump.

I had a 94 that did this. It was a bad fuel pump, sounds like you have the same problem. Good luck replacing it yourself, I believe the fuel pumps in these trucks are IN the tank, someone correct me if I'm wrong. One of the reasons I envy my brothers PSD, fuel pump in the engine bay ;-)

-Chris

If it runs on the back tank the relay and fuse are fine (OK).
You have a bad switch, wiring or pump in your front tank.

Here is a diagram:
http://i54.photobucket.com/albums/g9...el-sel1995.gif

i wasn't sure if they ran on the same fuse/relay or had separate ones. my front one was bad also, but i had the bed off my truck changing from styleside to stepside, so it was easy to do, but dropping the tank is not all that hard.

its in the tank. just siphon the gas out unbolt the tank and drop it disconect all hoses and wires from old pump reconnect to new one bolt tank back up no problem the worst part is the price of the pumps.

ugh! from the info here looks like I will have to replace the fuel pump. Looking at the wiring diagram it surely couldn't be the relay, also whe the truck sits in the garage there is fuel coming out of the charcoal canister ( i think that is what is called) what is causing that?

The front tanks fuel delivery module may also have a bad check valve in it allowing the tank to over fill while running on the back tank. This would force fuel out of the tanks vapor valve and into the charcoal canister.