No fuel to the carb

[LiveInspired]

My truck is a 79 C30. Camper Special. It had been running fine...hard to start if I didn't drive it often, but once started it always ran. Had some issues when you accelerate hard - kind of would drop out for a second and then take off. My cousin said that was carb related. I left it set for a few weeks and then it refused to start. Seemed like the carb was dry after many tries to start it so I cleaned the carb and went ahead and rebuilt it too (a first for me...but then this whole truck is a learning experience for me lol). Anyway, carb is back in and we have determined that the fuel was never making it that far. Fuel pump is working...but no fuel coming up in the line into the pump. Tried putting air into the line that runs down the length of the truck and my dad crawled under to see if the line was clear. He said there was a box under there that might have been leaking. We think it is the box that switches the fuel flow from the one tank to the other? Anyway, at one point some fuel came spilling back up out of the line...I think the air had created some pressure or something that caused it because that was the first time I'd seen any fuel make it that far. We already knew that the passenger side tank was inoperable and the guy who sold it to us just used the driver's side tank. Looked in the tank, because I'm in the process of replacing it (it has a small leak due to rust) the inside of the tank is very clean and the little sock/strainer was clean as well so the blockage/lack of fuel doesn't seem to be related to the tank. Any ideas? Like I said, I'm new to this so any ideas would be great. I really wanted to drive this thing this summer. It already sat all last winter...want to get her back on the road! Thanks so much!

[Jason S]

From your description, it sounds a bit like either the fuel tank selector switch on the dash or the fuel selector valve under the cab could be an issue.   

 Corrosion can form on the switch in the dash and not switch the fuel selector valve under the cab.  Here is a thread showing how to rehab the dash switch: http://forum.73-87chevytrucks.com/smforum/index.php?topic=6537.0

To test if there is power going to the valve under the cab, unplug the wire from the fuel selector valve and use a voltmeter to see if there is 12V power  whenever the fuel tank position is changed on the dash switch.

Without power to the fuel selector valve, it should be biased to a fuel tank (I believe passenger side on '80 model and back- but not certain). The valves have also been known to stick or hang in one position.

[LiveInspired]

i think it is successfully switching between tanks, but we are wondering about just running the hose direct from the fuel pump to the driver's side tank and getting rid of the fuel selector valve box thing entirely. I don't plan to use the other tank anyway. Is this a simple thing to do or would it mess something else unforeseen up if we did that?

[Jason S]

You can bypass the fuel selector valve. 

If there are emissions (vapor return lines) that have to be retained for state inspection, then you'd have to take those into account too.

[LiveInspired]

Thanks much!

[Irish_Alley]

yes you can by pass the valve like stated. but youre replacing one tank why not the other? i dont think theres anyway to tell which tank the valve is pulling from. the problem can be the switch like jason said it could be stuck on one tank or the other and i had no start problems due to the tank switch but this was on a tbi so it had fuel pumps in each tank. your name says "live inspired" welllll fix it right. it wont take much to take the switch off the truck and test it

[Irish_Alley]

found this courtesy of hatzie

http://forum.73-87chevytrucks.com/smforum/index.php?topic=29531.msg247201#msg247201
http://forum.73-87chevytrucks.com/smforum/index.php?topic=30556.0