Drivers fuel tank delivery problem

[sierraclassic86]

Howdy all, I replaced the drivers side fuel tank with an all new spectra tank and sending unit in my 86 gmc. Haven’t used the old tank in a couple years due to it leaking. Anyways, filled the new tank up and drove around town for a bit no problem. Went out on the highway and got up to 55 and started cutting out and sputtering. Switched over to right tank and everything went back to normal. Now anytime I switch over to the left tank it will start cutting out almost immediately. Checked fuel filter, looks fine. Took off fuel cap and that didn’t help. Maybe there’s debris in the line? I can hear the selector valve turn on and it switches tanks on the fuel gauge so I believe that works. Maybe debris between the fuel sending unit and the selector valve? The metal lines are in good condition. Anyone point me in the right direction?! Thanks

 

[RoryH19]

I think you are on the right track. Check for debris in the lines, make sure the rubber hoses aren't pinched... If that doesn't help could be your selector value. I had to change mine 4 years ago.

 

[dvdswan]

Check the line from the dr. side tank to the switching valve. If you have compressed air, disconnect the tank and switching valve and blow it out.

 

[sierraclassic86]

Sounds good! I will give that a try and see how it works out. Hopefully that’s all it is

 

[Conejo_K10]

When you remove the filler cap do you hear air rush in? Are you using a vented cap or does the tank have a 3rd vent line?
If it has a vent line, it may be backed. However, depending on the switch valve, the air may equalize when you switch tanks.

 

[bedwards]

I just went through this with my passenger side tank. It was like it was running out of gas. When I switched to the driver side, it was fine. I pulled the vent loose at the carbon canister, then pulled them loose at the selector valve. Blew them out from under the hood first, then the two vent lines after the selector valve into the tanks. I did not blow through the valve. Then I blew the supply lines out from the selector valve to the tanks, again not through the valve. Then I took the rubber supply lines off and replaced them as well as the clamps. My hoses were good so I have no idea what fixed the problem, but it did go away. I've put a couple hundred miles without a hiccup.

 

[C10MixMaster]

another possibility is sucking air through a loose or cracked supply line.

 

[sierraclassic86]

Turned out to be gunk in the metal lines. Lowered the tank and disconnected the lines at the sending unit and at the selector valve and blew through the lines with compressed air and a good amount of debris came out. Cleaned the lines and all works great now! Thank yall for the help! Appreciate it!