My 2005 F150 Lariat Supercrew project has a fuel tank issue. I started up the truck and had a large amount of fuel spill out onto the ground.

Not my area of strength, any suggestions what the issue could be (gasket, rust, etc)?

Thanks.

 

you posted 3 days ago and were told to look around the engine... are you saying it now is located by the tank ? Only thing that happens when you start the motor is the pump starts running and the line to the filter and up to the motor gets pressurized... look where the leak is coming from.

 

That’s correct. I was able to isolate where the fuel was coming from and it wasn’t the engine. The fuel rail, fuel injectors, o-rings all checked out fine. The volume of the fuel is coming from around the gas tank.

 

You need to pin point the leak area . Line from the tank goes to fuel filter under drivers side seat . Then it goes forward to fuel rail on top of engine . The fuel pump is in the tank so the pump sends fuel out the top of the tank around to the fuel filter. lots of area here . This is a fuel on demand system no return line to the tank . Some one is going to have to get under there and a helper turn key on, which starts pump . So it sounds like you have a leaking line that comes under pressure when key on . Do not run truck or get any hot surfaces going with this fuel leak . Better have a good extinguisher ready just in case . Not water.
Many fittings on top of tank ,one to charcoal canister,one pressure fuel output line(around 40 psi with key on ) , one evap test line . I don't think a gasket is your problem as the tank is not under pressure . Nor is there pressure on charcoal line or evap line . Not supposed to have raw fuel in those at all . Those are vac test ,and venting .
You could have a runaway fpdm module on rear axle ,check it for corrosion . Its a common failure point but not connected directly to fuel ,only controls the power to the pump. They get water inside and go crazy .

 

Thank you. Very helpful. To your point, I’ve spent this past week isolating the issue and the area. The truck lives outside by necessity so corrosion could definitely be playing a role in this issue along with the pump. Stay tuned. Thanks again.

 

rats get on top of fuel tank and chew on everything .

 

Could be rodent damage - I had it once but they gnawed on the EVAP hoses. They could just as well attack the fuel lines. It could also be a corroded hard line from the fuel pump. If a 2005 has the same gas tank as a 2007, its polymer, so its not a rusty gas tank. Typically the gas tank has to be dropped to get to any of the lines on top or to service the fuel pump so you will be better off doing this on a near-empty tank.
As for rodents, with fall/winter approaching, I'll tell you what I do, and it works. I have a spray can of '3-n-1Garage Door Lubricant'. This stuff has a strong spray and a strong smell. It's basically a strong silicone blend so its actually good for the hoses, etc. on top of the tank, and it seems to ruin the fun for the rodents. The strong spray with the permanently-attached 'straw' allows me to treat the tank-top area from the opposite-side wheel well so I don't even have to get under the truck. I also blast the FPDM with it, making sure to get it under the aluminum bottom plate. If you get rodents under the hood, you could blast the engine compartment wires and hoses with it too. I will use this stuff maybe once a year and on special times when it gets cold and snow is forecast. That's when they got me - one January it got very cold and snowed about 15". I don't drive this truck in the snow so I didn't dig it out - it sat until it melted, about two weeks. That's when I started smelling gas and soon got the engine light. Evidently squirrels, chipmunks or whatever got under the truck and then got snowed in, eventually gnawing on anything rubber they could find. They ruined every hose up there plus the filler neck adapter. I took it to the dealer which was a mistake, but I had a couple of other things done while it was there so the $1200 bill wasn't all for the damage.

 

1saxman,

Thanks for the feedback. Very helpful. I am convinced the the rodents played a large part in my gas tank issue for all the reasons you outlined. I appreciate the tip on the spray can of '3-n-1Garage Door Lubricant.

Thanks again.