I have a 2000 F-250 sc, swb, 4x4 PSD auto with 143K. When I have about 1/8 of a tank of fuel, the truck starts to run with a little more clatter. When in park, I can hear what seems to be a knocking sound under the hood. Then, once I fill the truck, the truck fires right after I start it and the knock ceaces. When I put my foot into it, the truck acts normal, with no detectable knock until I let it get down to stand-still idle. Is this a common issue? Normal? Something to do with air getting in the engine due to lack of fuel getting through the lines? Dirty fuel filter? Help out a fellow Stroker owner please!

 

This is caused by air entering the fuel sustem. If you do a search for the intank mod or the Hutch mod you will find a lot on the subject. The lines are connected with o-rings. O-rings seal pressure well, not so well in a vacuum situation. Check these sites for kits to repair. http://dieselinnovations.com/index.htm and http://www.dieselsite.com/

 

What Mech2161 said. I have done the mods that he mentions. WELL worth the time and effort to get it done.

 

The "in-tank" mod is what you are looking for. There is a secondary intake valve in the fuel tank pick-up assembly that is nothing more than a rubber flap over a big hole. This flap is offseated very easily, and I have pulled the pickup assembly before to fnd that it had fallen completely off (truck died just below 1/4 tank). When it comes off far enough to let air in the symptoms are exactly as you describe.

 

interesting stuff.... after i installed a fuel pressure gauge, i noticed that when the fuel level went down below 1/8th of a tank, the fuel pressure was extremely erratic. instead of holding steady at 65, it would fluctuate between 40 and 60. seems that it definately uncovers the pickup at that point....

 

Thanks for the tips fellas. I am curious though; could this end up becoming a serious problem? I know a bit about the truck, but I'm not really a mechanical genious. If I had this done at the dealer how much do you think it'd cost to get done? And what exactly would they do? Could I do it myself? Thanks guys.

 

it is probably something the dealer wouldn't do. it is modifying the OE parts, and ford doesnt "authorize" that.

 

Cookie, how exactly would I perform the "in-tank" mod? What would I need?

 

Just a bit of advise also when tanks get low it usually is harder to pick up fuel, plus the stuff in the tank has a higher concentration. If I was going to do anything in the tank I would take the bed off. I know it sounds weird but it is easier. All you habe to do it take 3 bolts out around the fuel neck. Unhook the tail lights, it just a plug in the ceter of the rear under the bed and 8 tourques bolts. fuel neck bolts are 7mm the bed bolts are a 52mm (I think) The beds arent that heavy four guys can easily do it and you just need to slide the bed back 3 or 4 feet. I would put a blanket or something on your rear bumper so that you dont scratch your bed. it will sit on it and your tires. You can do all of the work just standing there easy as pie.

If you take your tank down the wires and hoses are just long enough and they are hard to get to with the ned there. plus you would have to run it really low or empty. Just a thought. good luck

 

http://community.webshots.com/album/32614313yLKyrS

It's not as hard as it seems the first time through those pics, and there are kits available through several vendors.

 

Those are the pictures that I used to modify the pickup on my truck. I made the pickup tube long enough to extend down far enough to block the side pickup and reinstalled the pickup strainer. (The black mushroom head). It made such a difference in the way the engine runs that I recommend this mod and elimination of all quick connects between the fuel pump and the tank to anyone whether they think there is a problem or not. The before and after difference is amazing.

 

Thanks again for the tips. Honestly, I'd rather not mess with it because as simple as it may be, I'd probably screw it up. Are you fellas certain that the dealer can't replace something to solve the problem? I'm now aware that they don't do OE mods, but they must be able to fix it. Right?

 

It's more likely that will test drive it, tell you it's a normal sounding diesel, and send you on your way....but it won't hurt to try, except maybe in your wallet.

 

Haha I was thinking that but I guess it never hurts to ask.

 

Mech2161 posted a couple of sites that have kits available. None of them are site sponsors, so his links won't work, but you can see the IP addy.

Maybe get a tank mod kit and take it to an independant mechanic????

You could always just fill the tank when it gets down to 1/4.