Gas gauge not working? I think I fixed it.

Bill,

Most temperature sensors I am familiar with are NTC, or negative temperature coefficient. I have found that after sitting a long time (years) without use, they read open, however when heated they work again. It is as if the internal connection is made using a metal with a low melting point for connection.

Typically NTC have a standard nominal resistance at 25C. Then at a second temperature, check the NTC table to confirm. I typically use a second or third order polynomial to approximate the Steinthart equation, for use with EFI.

I found what I thought was a bad sensor, then found another, it was bad too. After heating to 100C both were working again.