just purchased a sending unit for my 66 olds f85 ....its supposed to be a chevy 0- 90 ohm ...but when i hook it up directly to an aftermarket gas tank guage on dash..it only registers quarter and full...whats up ..am i missing something.
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Perhaps the aftermarket gauge needs a different sending unit? Check the documentation for it to verify.

 

its a 0-90...ohm...i called the company up..but noticed that there is a resistor on the back of the stock guage...
any idea what thats all about??