Fuel gauge?, yes another one

[Mopower71]

Aftermarket gauge, and a Harwood 20 gal. fuel cell with sending unit.
What's the best way to check an after market fuel gauge?
Has a Positive, negative and the other pole for the sending unit.
It should be a 90 ohm gauge.
Is there a way to check the sending unit also? Without trying to stick my hand in the fuel cell, or removing the gauge? Tank is full of fuel.

 

[Mopower71]

If I check the sending unit with the Fluke meter, should it read 0 or 90 ohms at full tank?
Is there a way to check the gauge?
Help?

 

[prodart340]

disconnect the power, then read resistance[ohms] between the sending unit wire and chassis ground

 

[Mopower71]

Should it be close to 90 at full? or close to 0

 

[Mopower71]

When it's hooked up the gauge reads empty all the time.
With no power it goes below empty, when power is applied it goes to the empty line regardless of how much fuel is in the tank.

 

[bayyum]

almost sounds like the wires are setup backwards, EG: positive to negative, negative to positive.

 

[Mopower71]

Found the problem. After checking the resistance on the sending unit and finding the reading was close to 0. I pulled the sending unit and the plastic float is full of fuel.
Hooked the sending unit back up, and sure enough the gauge reads propperly.

Is there an epoxy that will seal to the plastic and also withstand the fuel?
Float is white but you can see the fuel in it.

 

[Mopower71]

Found one that should work