fuel system ?

[aggiemudman]

gathering all the parts for tpi swap and wondering what to do with the fuel lines. I need to upgrade to a 3/8 sending line and a 5/16 return line. How do you route the return line on dual tanks?

Does the sending unit have a return line on it already? The ones on my truck have 3 tubes. Im thinking that one is a vent, one is the sender, and on the return. Am i right?

:confused:

[robertf03]

i've never seen how chevy did their dual tank valves, but ford had half a dozen or so different designs. Does your truck have a factory return line?

[Graystroke]

I've always wondered how the valve worked on dual-tank set-ups. Is it vacuum or electric. My dad's '86 is still working w/ 335K on the clock so it must be a good design. ...except for the fact that they blow up when you get broad sided! especially when a rocket igniter is placed next to the leaking fuel...gotta love Dateline...and so did GM's lawyers...

[robertf03]

some of the fords had the low pressure intank pump and the switch on the dash just changed pumps. the valve automatically fed from and returned to the line with pressure before feeding the external high pressure pump

[Graystroke]

the '86 we have has a mechanical pump on the block..this is the ****ty old school GM hybrid electric carb we are talking about!

[aggiemudman]

its switch operated, im pretty sure its electric. but im not sure what the lines do. like i said theres 3 lines that go into each tank. im just wondering if there is a return line or not.

[Graystroke]

how many lines go to the engine compartment? I guess that one goes to some type of evaporative system(charcoal canister?), one to the pump, and maybe the last is a return. Do you have a prts book? Or a manual? I look and see. You could just climb underneath and trace the lines to where they go and decipher from there.

[Graystroke]

this should help. you owe me a beer.