Troubleshooting Aux Fuel Valve Connections

Engine, ignition, fuel, cooling, exhaust

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Redcrew71
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Troubleshooting Aux Fuel Valve Connections

Post by Redcrew71 »

Have a 71 f250. has the longer inside frame aux fuel tank with the valve besides drivers seat valve and the under dash fuel gauge switch.

It has been running on Aux. my gauges done work. (I am working on that more below). I notice that under truck one side of the 3 way valve is disconnected. Wondering if this means
a) my cab tank is disconnected?
b) the Aux tank may be plumbed direct to motor & the valve is not used.
fuel5.JPG
The one on the bottom is coming down from cab tank above.
In grounding out the sending unit wire my cab tank goes to full. Where is the aux tank sending unit located on the tank...can one reach it by taking the steel cover off the tank? front back top?

Thanks
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cdnwillyg
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Re: Troubleshooting Aux Fuel Valve Connections

Post by cdnwillyg »

On my aux tank the sending unit is right by the U-joint facing the center of the truck. No need to take anything off. :thup:
1968 Mercury M250 Camper Special
FE-390,570CFM 4bbl, C6 Automatic, PS, PB front disk.
Stony Plain, Alberta, Canada
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colnago
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Re: Troubleshooting Aux Fuel Valve Connections

Post by colnago »

From the photo, it looks like your valve is not connected to your fuel pump. Your inside tank, yes, but the other ends of the valve aren't going anywhere.

Joseph
"Sugar", my 1967 Ford F250 2WD Camper Special, 352FE, Ford iron "T" Intake with 1405 Edelbrock, Duraspark II Ignition, C6 transmission, front disc brake conversion.
Redcrew71
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Re: Troubleshooting Aux Fuel Valve Connections

Post by Redcrew71 »

colnago wrote:From the photo, it looks like your valve is not connected to your fuel pump. Your inside tank, yes, but the other ends of the valve aren't going anywhere.

Joseph
me thinking that the valve is totally bypassed and the previous owner just ran the back tank direct to fuel pump
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Re: Troubleshooting Aux Fuel Valve Connections

Post by basketcase0302 »

me thinking that the valve is totally bypassed and the previous owner just ran the back tank direct to fuel pump
From your picture your right-the dual tank valve is not doing anything and your probably running off of the rear tank, (the looped rubber tubing in your pic). :(
Jeff
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SOLD-71 F-350 dually flatbed, 302 / .030 over V-8 with a "baby"C-6, B & M truckshifter, Dana70/4.11 ratio, intermittent wipers, tilt steering, full LED lighting on the flat bed, and no stereo yet (this way I can hear the rattles to diagnose)! SOLD!
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colnago
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Re: Troubleshooting Aux Fuel Valve Connections

Post by colnago »

The good news is that this probably means your aux tank is clean and solid. It should be really easy to plumb everything back correctly. Or, you can leave it as-is, remove the main tank from the cab, and have a bit more storage room behind the seat.

Joseph
"Sugar", my 1967 Ford F250 2WD Camper Special, 352FE, Ford iron "T" Intake with 1405 Edelbrock, Duraspark II Ignition, C6 transmission, front disc brake conversion.
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