7.3 Fuel Lines/ Stalling while driveing

[Kelleyj1837]

I have a 1990 F-250 7.3 IDI, We are putting in new fuel tanks and the kid who had it before me ran rubber fuel lines and left so mutch extra line its got a huge lupe right next to the transfercase. We want to replace them but schould we run rubber or steel lines? Also what size line is stock for the truck. We are thinking the truck is sucking air beacuse it will stall out driving it when it gets below a half of tank of fuel. and at the top of the fuel/water seprator when it stalls and you hit the valve that lookes like a bycicle tire just air comes out. Then you can bleed it a few times and it will eventually start.

 

[Agnem]

Sounds typical of a rusted fuel pickup. When you replace your tanks you will discover if this is the case. Stock lines are, if memory serves me correctly, 3/8" for fuel to the engine, and 5/16 for the return line. You can do rubber or metal. Makes no difference to the truck. Ford uses steel for collision reasons, but I've had rubber on all my trucks and never had an issue.

 

[icanfixall]

Welcome to the forum...
The above posting about the line sizes is correct. As for running out of fuel at 1/2 tank... Well thats funny because we usualy see this happening at 1/4 tank because the fuel pickup in the tanks breaks off. Then you can't suck the last 1/4 tank. If you fill the tank after this happens and only get about 12 gallons to fil it up then you found the problem. the fix is easy. Just remove the sender unit and add 3 inches of rubber hose to the fuel sender pickup. Search this forum for information on doing this.

 

[subway]

Mel nailed it, the stock showerhead pickups in the tanks are known to disentagrate in the tank and you start pulling big gulps of air at about 1/4 tank. if it is pulling air at about 1/2 you probubly have a problem with your pickup line. that bicycle vale is schrader valve and is for purging air out of the system.

is this the mid or rear tank, if it is the mid tank there is enough room to sneak out the sending unit for a look. if it is the rear you will be droping the tank for a look.

 

[Kelleyj1837]

It is the mid ship tank that it is ran on, the rear leaks a lot. So when doing new tanks and lines would you recommend getting new sending units? Both gauges work well but i don't know if there is a filter inside of the sending unit, that needs to be replaced.

 

[subway]

No filter per say on the sending unit. It looks like a rubber shower head with a metal screen on the bottom. They tend to disintegrate over time, many here have just used a piece of fuel pine to replace it. Then they notch the bottom so it does not suck down solid to the bottom of the tank.

If the rest of the sending unit is good I would try to keep it. Not sure on your truck but a sending unit for my truck was in the 160-170 range to replace from Ford. Not cheap.