Ok, I am sure this has been covered before and if so I am sorry....but

Ok, 195K miles and the fuel gauge will not register below about a quarter tank. It performs fine from full to just above a quarter then it just stays a little above a quarter until i run out Unless you have kept track of the mileage it is a guessing game as to when I will run out.

SOO I am planning to drop the tank and replace the sending unit (if I can find one aftermarket) and when doing so I want to do the Hutch/Harpoon. My question is do I need to buy a new sending unit and then do the hutch mod to the new unit, or could the problem in my tank be fixed by simply dropping the tank and doing the hutch mod to the existing fuel sender?

Thanks for any suggestions

 

Sounds as though the Pick-Up Screen has broken off which is a relative common problem. The sending unit is most probably reading correctly. You can confirm it's reading using a DMM. You can purchase a new pick up for about $30 and perform the Hutch-Mod during replacement. The Harpoon mod will provide you about 5 gal additional fuel.

 

Someone will have to correct me if I'm wrong, but you'd have to Hutch the new sending unit. You'd have to remove the screens in the mixing chamber and extend the return line on the new unit. But I haven't done this mod, just read about it.

However, I'd consider dropping the tank and checking out your current unit before you spring for a new one. I can't see any reason for your issue other than the float simply hanging up on something in there. I know potentially dropping the tank twice sounds annoying.

As I said, hopefully someone will put me in my place if I'm wrong.

 

Double post, sorry guys

 

Thanks for the response. The only thing I am confused about is I thought the sending unit had a float switch type of arm that measured the fuel in the tank with resistors. And I figured the resistors went bad and the sending unit might need replacement. But your post makes sense and BTW what is a DMM? I am hoping the screen broke off the bottom which is a very common problem, I just didn't know that when the screen broke off it would affect the gauge?

Thanks again

 

Welcome to guzzle's In-tank Hutch Mod Web Page look at the pictures. Now you know exactly what you're gonna see when you drop the tank. If I had to guess I'd say something is getting hung up on it's way down. It's a smart idea to have a new pick up foot and not need it then to not have it and need it. A brother here sent me one via mail and it turns out I didn't need it. Our deal was if I didn't need it to send it to yhe next guy who might need it... And I did... Where it is now is anyone's guess.

 

The screen breaking off wont effect the gauge reading. You will have to do the H and H to the new one. I think someone has said the pickup unit for a V-10 will work, and is much cheaper, maybe because it doesn't have the mixing chambers, but don't know for sure.
DMM is digital multi meter. I think.

 

The reading isn't affected, the amount of fuel that can be removed from the tank is. The sender float never makes it to the bottom of the tank if the pickup foot is broken off. You probably don't need a whole new unit, but it would be a good idea to have one on hand just in case. Especially if you don't have a second vehicle . . .

 

I'm always a fan of having a backup so as Pikachu and John said, it's better to have and not need then vice versa. I still think your float arm is hanging up possibly, but you should check out the pics on Guzzles page to make your own assessment.

 

Here is a link for the replacement P/U Tube w/Screen Fuel Tank Pickup Screen $37.95 + Shipping.

You can also get the good deal searching. Regardless of length; Just cut it down to and adjust the float when you install it. I think it's 13.5" from top of the unit to the bottom of the screen.

I picked a new unit up for $125 from e-bay and cut it down. It was for a F450/550 40/50 Gal Tank. The one for the 250 runs about $300-$500 new.

The Hutch Mod: Many people do the Hutch Mod to prevent air from being picked back up in the supply side causing cackling. Personally, I did not do the Hutch Mod when I changed the unit this past summer.

The Harpoon Mod: I was getting right about 325miles @ 25 Gal Tank. Following the Mod I get just shy of 475 miles per tank when the Low Duel Light Activates and it holds near 34 Gallons now and the pump only cuts off once. And, I also used a Dremmel tool and opened the filler neck up which allows me to fill up at a lot of truck stops which otherwise I could not do in the past.

Be sure to inspect the Mixing Chamber Pre-Filters if you only replace the P/U Tube as they are often contaminated with debris. When I did mine they were like new with 200K+ Miles. But, I've always added a fuel conditioner ever-other fill up - Whatever is on sale works for me.


You will need a 5/16" and 3/8" Quick Disconnect Tool

 

when you drain the tank down,that should confirm the sending unit condition.