New Tank, New Sending Unit, NO FUEL

[Hubscrub]

I replaced the driver side tank on my 85 K10 and installed a new sending unit since my old one wasn't reading anymore. So i can not get gas to the carb from that side passenger tank does fine. So i bypass the switch tank valve and plumb the new tank directly into the lines to the pump still no fuel. Took tank back out checked sending unit etc. blew air through lines all clear. Did notice that return port on sending unit seemed hard to blow through. Reinstalled still no fuel when i take the 3/8 line off they is pressure released from it. Could the sending unit be bad? Im at my whits end. Thanks

[JJH Jimmy]

Are you sure the rubber fuel line for that sending unit is not kinked? I’ve had that problem before.

Was there any trash in the tank when you replaced the sending unit? The transfer line from that tank to the transfer valve could be plugged. Try unhooking the rubber lines from each end and blow some compressed air through it.

Possible transfer valve is plugged?

[cadillac_al]

I would be using my Mity Vac to see how much vacuum it takes to pull gas from that tank.

[kwmech]

Are you sure the valve is switching

[Hubscrub]

Originally Posted by JJH Jimmy

Are you sure the rubber fuel line for that sending unit is not kinked? I’ve had that problem before.

I thought i was sure.

Originally Posted by cadillac_al

I would be using my Mity Vac to see how much vacuum it takes to pull gas from that tank.

I did take that advice.

Ok, i took the tank out for the fourth time and hooked it up on the floor truck ran fine. Reinstalled it no fuel. I took my mighty vac and sucked on the 3/8 line at the transfer switch end no fuel. So i loosed the tank and dropped the rear just enough to feel a kink in the lines. So i cut about and 1 1/4 in off all of them and pushed it back up. OK FIXED!! I was about to pull it out of the shop and noticed my fuel gauge wasn't working.The wires were pinched between the frame and tank bracket so i loosened for the fifth time and got that took care of. While i was doing that i noticed gas spraying out of the 3/8 hose at the switch so i have to replace couple rubber hoses and i'm done.

Saying all that to say this thanks for the advice, i really feel stupid not catching such a simple thing.

[mongocanfly]

good deal...im impressed you found something a mightyvac was good for..!!

[Hubscrub]

OK so I hate loose ends on threads. I thought I fixed it the wife took the truck and was takeing brush off to the dump. She filled the new tank and switched it over and died in the road. She switched it back, got it back home. MONTHS later, I decide today to pull it in and was gonna drop the tank again. But I though I'll try and sneak my phone up there and take a picture. Well the 3/8 rubber was kinked apparently the hard line got pushed over during all that work and was kinking the line. I reached up and move it back like it was suppose to be and that straightened the rubber out. I just laid there and laughed. All that trouble for that. So I'm just saying this just incase someone else finds there self in this situation in the future. Oh the simple things we overlook.

[kwmech]

That'll certainly stop things up a bit