i have a dual tank system does anyone know if it will automatically switch when one tank runs out? I topped off my front tank for the first time and it took 9.5 gallons and ive since put 150+ miles on it. i had put about 6 gallons in the rear tank at the same time . my sending unit for the gauge works on front but not the rear and ive put about 30 miles on it on dead empty i had thought this 351 only got about 11mpg so if anyone has a owners manual id like to know how this system works ive been trying to run the front tank dry so i can figure out my capacity thanks!

 

It will NOT switch automatically. If the truck is pulling fuel from both tanks at the same time, I would check the fuel selector valve on the framerail on the driver side for malfunctions. Gas Tank Capacities. Short Bed. 16.5 gallons Front Tank 19.5 Gallons Rear. total 36 gallons. Long Bed 19.5 Gallons Front, and rear. Total 39 Gallons.

 

It's common for the selector valve to fail.

Ford part number > >

E5TZ9189B .. Fuel Selector Valve ~ 6 ports ~ Marked: E57B-9F271-AA or E67B-9F271-BA.

MSRP: $200.98 / ftepartsguy.com price: $144.71

 

well thanks i must have a bad sending unit up front too it must be regestering empty with a half tank oh does ext. cab change capacity? it is a short bed i believe

 

will pulling from both tanks at the same time cause a problem? i was running off the rear tank once and it started stumbling when it ran out so i switched to my front tank and it started running right away

 

Fuel senders also are prone to malfunction on this year range of truck. Though most are obsolete at Ford, some aftermarket companies have begun to reproduce them on certain year models.
Don't make a difference super cab, or regular cab.

 

Yes, it could cause you to suck air from the empty tank. Causing sputtering.

 

i dont want to hijack this thread but on my 86 efi with dual tanks if i fill both tanks and flip the switch to the rear the gas pours out of the front tank, would this be the selector switch malfunctioning?

 

Fuel tank senders.

I can run all the part numbers for y'all and see what's available...

But...I need to know which tank (front or rear), the engine size, the trucks wheelbase, and whether it's a steel or plastic tank.

CAVEAT EMPTOR: REPRODUCTION SENDING UNITS? = NOT!! > >

> > Some of the aftermarket suppliers (like the outfit in Kansas) are buying fuel senders from Ford and listing them in their catalogs.

The price is usually 20-30% ABOVE the Ford suggested retail price (MSRP).

WHY pay that price if the senders are available from Ford?

You can buy them from ftepartsguy.com at 25% OFF MSRP!!

 

It's a 98% probability.

 

Thanks for the heads up about the sending units Bill.

Makes it all the more imperitive to check with Ford for parts first, then go aftermarket if you have too.

 

ok with my rear tank empty i run fine..no sputtering so i must just have two bad sending units thanks for the info!

 

if its a 6 port type valve, your return lines could be in the wrong order. so the gas thats supposed to be returned to the rear tank is actually being sent to the front tank causing it to overflow

 

He does have the six port valve on his truck. But I doubt the lines have been crossed. If they were crossed the rear tank would overflow when switched to the front tank, as well, but it doesn't.

That's exactly what's happening, but I believe it is a malfunction with the switch itself. As I said earlier if it was hooked up backwards it would overflow both tanks in relation to which tank was selected.

 

hi i have a 1981 ford f150 with dual gas tanks it is a 302 engine 4 wheel drive and one day i switched to the back gas tank and know its stuck on the back tank how do i switch it back to the front tank the switch wont work.