I PURCHASED A F-250 W/A V-8 302 WITH DUAL TANKS THAT WERE BOTH LEAKING.I REPLACED THE REAR TANK WITH A NEW ONE AND NOW WHEN I PUT FUEL IN REAR TANK IT PUMPS IT TO THE FRONT TANK.THE TANK SWITCH ON DASH IS SET TO REAR TANK WHEN THIS HAPPENS. THANKS
Hi, My brothers 250 had the same problem and is now fixed.The fuel pump in each tank has a check valve that allows the fuel to run in one direction only. When this valve fails to close fuel runs into that tank when the other pump is running. We replaced the pump and all is well. Dan
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
I see that you have not received an answer yet. I had a dual tank Diesel which had a switch under the dash to change tank feeds. Both tanks reported fuel amounts to the same fuel gauge as each tank was switched on.
If this is the system you have (using gasoline) then simply turning the dash control should isolate the rear tank. If yours is different, you need to look underneath the truck at the fuel line routing.
For gasoline engines there was an idea to meet EPA Emissions standards by closing the fuel loop. This meant that unused fuel that was brought to the engine was returned back to the fuel tank. Some things were different for Trucks by weight Class and because of the EPA rules, trucks keep their carburetors while cars went to fuel injection. The "light" Trucks changed to fuel injection before "heavy" Trucks.
Most of the fittings to fuel components can have a taper machined to match fuel components only. There can be different thread seats, even Metric for replacement parts. Your best bet to match components is disconnect the problem part, take it with you, and then get a cap plug to block the flow. This is providing that the rear tank does not need the loop anymore.
Check tanks for balance tube between tanks If the air pressure is not allowed to equalise between tanks then the vacuum formed will not allow fuel to flow to the pump. Breathers on both tanks are a start.
Have the same truck and had the exact same problem. Mine spilled out the front tank. Ford did a recall on this problem. They put valves on the lines outside the tanks. Mine had already been done so that was not the problem. The pumps have valves inside for the return lines. I replaced the rear pump, didn't fix it. Replaced the front pump and Voila ... it was fixed. Bad valve in the front pump return line.
Make sure you have the check valves in place on the lines at the sending units on the tanks. If the switching valve on the frame rail goes bad it can push fuel back up the return to the opposite tank than you are pulling from causing fuel to push up and out the inlet. If these were not removed and replaced on the new sending units they will have to be purchased from the dealer.
It should not cause no problems but instead of removing the tank leave it in the truck take out all the fuel in the tank and jus discontinue use of it. This will save you alot of time and trouble and i also suggest that if anyone besides you drives this vehicle then i would put a locking gas cap on it so it cant be accessed at anytime except by you.
Try putting a new fuel pump in it or check the fuel tank switching unit it might have failed. (switch or unit under truck).I would go under truck and try to isolate one tank both electricaly and mechanicaly the see how it runs.