Fuel Gauge / Sender not connected/working?

[ak_garner]

Hey gang:

My 66 Wag has a modified fuel tank in the back. I was told it's off a Chevy s-10. It also has a Holly red fuel pump.

I'm just trying to get the fuel gauge to work / always shows empty and was told by previous owner it had worked before tank was installed. So, any ideas how this is set up? Is there a potentially a sender in the tank that's not sending the right resistance for the fuel gauge? Is there maybe just a hose into the tank that the Holley is pulling from, so there's no pump, and maybe not even a sender? Super confused how this might be rigged without pulling it apart.

Thanks for any thoughts.

[tgreese]

Why are you reluctant to pull the sender out of the tank? Easy if the top of the tank is exposed.

Are you trying to use the factory gauge? The sender in the tank is a variable resistor moved by a float. The gauge has to match the sender. With the sender out, you can pull the sender out and measure its resistance at full, half, empty. The values for the factory sender are in your TSM. The '72 TSM says 9/23/72 ohms for full/half/empty resp. '66 is likely the same.

Even if there is a fuel pump in the tank, that won't make any difference to how the sender and gauge works. The extra lines are probably for vapor recovery on the S10 donor, or maybe there's a fuel pump in there that's not being used.

[ak_garner]

Not reluctant to pull it off, just 1: ran out of time, and 2, I can't get the yellow plug off and I don't want to break it. It wouldn't budge, so not sure how corroded it is. I need to pull the plug and lines and work the opening.

Extra lines had me confused - makes sense they'd be for an evap system! Thanks for that info.

I'd like to use the factory gauge, yep. Thanks for the resistance numbers. I'll work on this a little more - getting eyes on the sender in there - and the wiring to the gauge.

Thanks!