Rear fuel tank does not work; gauge shows empty
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Rear fuel tank does not work; gauge shows empty
Good morning! This is my first post and I'm grateful for any help anyone may be able to offer.
I've owned a 1986 F-250 6.9 diesel for a few years now, but yesterday I purchased a 1985 F-350 7.5 with a 460 big block carb. It has dual fuel tanks and the front tank seems to work properly. The rear tank was bone dry when I bought it, so I filled it up with fresh fuel. Here's the problem...when I switch from the front tank to the rear tank, the fuel gauge on the dash drops to empty and the truck dies shortly afterwards (presumably after the fuel in the carb is used up). Has anyone ever had this happen to them? I'm at work right now, but I plan on checking fuses and relays tonight, as well as power to the selector valve and the pump. Again, any help would be greatly appreciated. Thank you!
I've owned a 1986 F-250 6.9 diesel for a few years now, but yesterday I purchased a 1985 F-350 7.5 with a 460 big block carb. It has dual fuel tanks and the front tank seems to work properly. The rear tank was bone dry when I bought it, so I filled it up with fresh fuel. Here's the problem...when I switch from the front tank to the rear tank, the fuel gauge on the dash drops to empty and the truck dies shortly afterwards (presumably after the fuel in the carb is used up). Has anyone ever had this happen to them? I'm at work right now, but I plan on checking fuses and relays tonight, as well as power to the selector valve and the pump. Again, any help would be greatly appreciated. Thank you!
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Usually the motorized valve mounted on the frame goes bad. It switches the lines, and also has a switch built into it, and switches the sending units electrically also. When you get under there, that will be all the extra wires going to the valve, that is the sending unit wiring.
It would be a good idea to get a meter and check it out electrically, but most of the time it's the valve.
Don't be surprised if you get the valve working and it picks up fuel from the tank, but the gauge still doesn't work. The sending units are notorious for going bad on these trucks. Also realize you more than likely have electric pumps in each tank, so there is something else to go wrong. Double check your fuel system, they had different versions and then previous owners get in there and modify and sometimes add pumps on the frame also.
It would be a good idea to get a meter and check it out electrically, but most of the time it's the valve.
Don't be surprised if you get the valve working and it picks up fuel from the tank, but the gauge still doesn't work. The sending units are notorious for going bad on these trucks. Also realize you more than likely have electric pumps in each tank, so there is something else to go wrong. Double check your fuel system, they had different versions and then previous owners get in there and modify and sometimes add pumps on the frame also.
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