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A. Penland
A. Penland, Ford Senior Master Technician, ASE
Category: Ford
Satisfied Customers: 6601
Experience:  ASE Master Certified, ASE Advanced Gasoline Engine Performance
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Ford f250: I have a 93 f250 7.5 gas engine, dual tanks that

Customer Question

I have a 93 f250 7.5 gas engine, dual tanks that I recently purchased? The Previous owner said the front tank fuel pump was bad. The rear gas tank was sending fuel to the front tank. I changed both FPM, pressure reg. & fuel filter. The truck won't start on the front tank. Switch to rear tank and it starts right up; switch back to the front tank and it runs fine. If I run on the rear tank, fuel is sent to the front tank causing it to overflow. When running on the front tank, the tank won't overflow, the gas gauge stays full, seems to be pulling gas from the rear tank( based on the rear tank gauge reading). Any ideas.
Submitted: 2 years ago.
Category: Ford
Expert:  A. Penland replied 2 years ago.
The problem is the front fuel pump in the fuel tank. It has a check valve that stops fuel from filling the fuel tank it is in when the other pump is running. You will need to replace the fuel pump assembly, not just the pump motor to fix the problem.
Customer: replied 2 years ago.
I replaced the whole assembly in both tanks.
Expert:  A. Penland replied 2 years ago.
That I did not know. Ford did have a Recall out on the F Series back in the 1990's where we installed check valves on the front and rear fuel pumps to stop this from happening.Below is the actual recall and parts numbers you will need.
Expert:  A. Penland replied 2 years ago.
Please let me know if you need any more help.
Customer: replied 2 years ago.
Yea, I thought changing the pressure reg and fuel pump assemblies was
In lieu of that. Why would tthe rear tank burn gas when the switch is set on the front?
I'm wondering if the rear back flow line could be clogged, causing it to go to the front tank?
I guess it's possible they sent a bad pump. Just trying to find out if there could be another reason, before going through that lovely task again ūüėĀ
Expert:  A. Penland replied 2 years ago.
Earlier models F Series had a selector valve to control the fuel pumps and fuel flow. Make sure they gave you the proper fuel pump for your year truck.
Customer: replied 2 years ago.
I got the problem resolved. I changed the front/rear tank dash switch. I guess the switch was not allowing the proper voltage to the front pump,or was kicking on both pumps, causing the malfunction.
Expert:  A. Penland replied 2 years ago.

Thank you for the update.