fuel supply - at my wits' end!

[cstanley]

i can't figure it out. i must be missing something simple. i still can't maintain fuel supply after about 5 miles of run-time. i've replaced hoses, fuel pump, fuel cap, and tank sending unit (good news: fuel gauge works now!) i just can't figure it out! (see this post for my symptoms: http://www.67-72chevytrucks.com/vboa...d.php?t=191092)

i did, however, notice last night that the front vent hose (not yet replaced) that attaches to that smog canister by the battery was disconnected, and the restrictor inside the hose was shot. also, the cap on the canister looked to be missing. it hasn't always been that way, but i can't remember when it might have come off. could this be my problem?

maybe pressure is keeping fuel from flowing to pump? problem seems to be on the supply side of the pump. when it stops flowing, i disconnect the supply from the pump-no gas, but after a few moments, it will start to flow again.

I AM SO FRUSTRATED WITH THIS!!

[diver547]

does your fuel lines run close to the exhaust?......possible vaperlock problem

[cdowns]

try running it without the gascap for a test run , also change the rubber hose section under the cab

[cstanley]

i'll check all those, thanks.
any thoughts on that canister? does it need to be hooked up?

[Jayss109]

canister is not needed to make her run, just vents excess vapor to be burned off. Mine went to the scrap heap years ago, just plugged the hose coming outta the tank.

J
________
Russian recipes

[qksilver]

like cdowns said, sometimes the rubber hose will collapse under suction, even though it looks good on the outside, i ran into that problem on a couple of trucks because the P/O's didn't use fuel line but vacumm hose

[cstanley]

thanks, i'll make sure all my hoses are newly replaced.

[cstanley]

woo hoo!
i think it's fixed! hopefully i'm not jinxing myself, but the initial testing stages indicate success. i really don't know exactly what the problem was, but i suspect it was a collapsed hose under the cab, as cdowns said. anyway, the result of my efforts are: a new fuel cap, new tank sending unit, new hoses, new fuel pump, new inline filter. now it'll go further than 5 miles and the fuel gauge works (hasn't worked in about 8 years.) the sending unit was shot, rusty, no longer had a filter, and the float arm was stuck. at least now i can leave the gas can at home.

all of that, and i'll soon be switching the tank to an under bed tank anyway.
oh well, that's the way i roll...

thanks everyone for your help! this site rocks!