Hi, I just bought a 1990 F250, 7.5L 460cc (gas). It's a beast, and a I just had the heads redone by a mechanic.

My most immediate problem is my fuel system (dual tanks). These are my symptoms:

When the selector switch is on the front tank, the fuel gauge incorrectly reads EMPTY, but the engine runs and receives gas.
When the selector switch is on the back tank, the engine dies immediately and receives no gas, then the fuel gauge correctly shows FULL.

So my two problems are the fuel gauge on the front, and I don't know what on the back. Do I need to replace the pump, is it possibly electric? (I already changed the fuse for the selector valve).

Today I will switch the tanks and listen to the selector valve to see if it is working. Should I switch that out before moving forward (with dropping tanks)?


My other, unrelated, problem is that I don't know the name of a part and need a new one. It is a big plastic connection between the radiator/grill area and the air filter. It has an accordion style bend, and has fallen apart (so it is sucking hot outdoor air).

Thank you for any help. I am a beginner so please speak in laymen terms!


1987 1988 1989 1990 1991 1992 1993 F150 F250 F350 Fuel injection selector valve fuel pump fuel gauge dual tanks

 

To start with you do not have a selector valve in a 1990 truck.
That said it sounds like the float has sunk in your front tank and the rear tank has a bad pump in it.
The sender and the pump (FDM) are sold separately and are separate items.
You can also buy the whole unit with the hanger, FDM and gauge sender together but the cost is more than some want to pay.



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Thank you. I went under the truck while my buddy switched the tanks, seems like you're exactly right. Where do you recommend I buy those parts, and any tips on taking the bed off?

 

To start with there was an error in one of the lines I wrote above.
It should have read:
"The sender and the pump (FDM) are sold separately and are separate items."

You can buy the FDM (with the pump inside of it) at any auto part store or on line at Rock Auto.

The gauge sender is a different matter. The sender can cost almost as much as the FDM.

The FDM:


The gauge sender:


A photo showing the gauge sender attached to the FDM and the hanger:


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Thank you. I have been researching pumps, and I can buy the entire assembly including the sending unit for around $100. I think I am willing to pay that (I can get a pump alone for around 30-40).