Running out of fuel before I'm out of fuel...

[kitchene]

I have a 2000 F550 with the aft axle tank. To my suprise one day after I got it last summer, my fuel light came on, and about 2 miles down the road I'm out of fuel. Needle is still over empty and all that. Filled the truck up and it only took about 35 gal if I recall correctly. The tank is a 39 gallon tank, so I should have had 4 gallons left. this happened another time, about the same way. well I was comin home last night, truck is just below 1/4, light not on, as I was trying to get as much out as possible because I wanted to address this issue as well as a pinhole leak in the tank. to my surprise I'm almost home and ir runs out.

Now usually I put fuel in, run the key a couple cycles to reprime it, and fire it up. It will run like crap for a few miles then clear up and run great. Last night, I put a 5 gallon can in it and it wouldn't start. It was trying but nothing. so I let it set overnight with the charger on it, still won't start today. Pulled the filter, looks good, but fuel is a little murky in the bowl.

So, does anyone have any ideas on why this could be happening?

Something else that may be a clue is the truck will go 150+ miles when the gauge reads 3/4 tank, but after that the gauge drops like a rock.

Thanks

[7.3Lariat]

Maybe the measuring piece is sticking in the tank. Some guys I have heard beat on the tank with a rubber mallet see if that dislodges it.

[Rockyardjo]

Don't know about the gauge problem but maybe your pickup tube in the tank is cracked or broke.

[Chakir]

Not sure if they work the same but my car's gas gauge reads high now due to the ground from the sensor becoming corroded. I can "fix" it by running a few tanks with heat mixed in. I don't know if there's an equivalent in the diesel world or not. The permanent fix is to drop the tank and replace the sender.

[white99]

I had the same problem. There is a rubber check valve or plug on the pick-up tube in the tank...it probably came out. Sucks air when you still have 5 gallon in the tank.

[AnthonyU]

Yeah I had the same problem and I heard that the plastic pickup or little foot becomes cracked inside the tank overtime and the fuel is running out before the needle drops down to empty you have to drop the tank to fix it

[kitchene]

Originally Posted by white99

I had the same problem. There is a rubber check valve or plug on the pick-up tube in the tank...it probably came out. Sucks air when you still have 5 gallon in the tank.

White, is that the little piece that looks crimped? Should it be open? I don't see any cracks or anything in the plastic. It's really driving me crazy seeing as though it had 8 gallons left in the tank when it ran out.

I took a picture and will post it soon as it emails from my phone to my pc.

[kitchene]

Should that be open?

[kitchene]

This is making my crazy. I haven't found anything wrong with the unit in tank that I know of. And that isn't saying much because I can't find any information about the operation of the in tank unit. Because It's an aft axle tank without a fuel pump in the tank, I can't even find the parts on the ford parts diagram. I'd hate to put the thing all back together without solving the problem. Does anyone have anymore ideas?

Thanks,

[white99]

Sorry for not replying...mind is elsewhere. It is not the orange piece you have a pic of but it is the black circular cavity behind it (also in your pic)...if I am remembering correctly. Is there a plug or cap in it?