dual tanks only one works

[zoomiah]

I have a 79 gmc sierra grande stepside that was originally a diesel converted to 350 gas with dual tank setup. Only one tank works all the time, when i switch to the other tank at highway speeds it lags and feels like it doesnt seem to be getting enough fuel, anyone know why or how to fix this? thanks

 

[Stroked]

Hmm...that's a tough one to diagnose. Could be the pickup is full of crud in that tank or a plugged line.

 

[Jims86]

Hmm...that's a tough one to diagnose. Could be the pickup is full of crud in that tank or a plugged line.

good call. the selector valve could be gummed too.

 

[smurph20]

With mine the old fuel lines were breaking down and plugged the valve up.

 

[zoomiah]

Thanks for the responses guys! is there anything i can do to try to figure out what it could be for sure? any help is greatly appreciated!

 

[towjoe]

Are you holding the switch valve on long enough for it to fully switch? Could also be a pin hole in fuel line on second tank drawing air.

 

[Jims86]

Best advice is to go ahead and replace all the rubber lines. may fix it, andnwill give you piece of mind.

 

[zoomiah]

I will work on replacing the lines and see if that fixes it. they need new ones anyhow! thanks guys

 

[td87]

2 different fuel pumps? Because I had a similar issue with my aux tank, replaced the pump and it fixed the issue