Topless69GT 28 Report post Posted May 2, 2018 My fuel gauge has never worked since the car was restored. I assumed it was the sending unit in the gas tank. I was going to address the issue this spring. However, I got the car out of storage a couple weeks ago and now it is working about 1/2 the time and is reading accurately when it does work. Need some help trying to figure out what the issue might be. Is it the gauge, wiring, or the sending unit? Quote Share this post Link to post Share on other sites
69RavenConv 286 Report post Posted May 3, 2018 Something's intermittent, either the CVR, the wiring, or the sender. If your oil pressure and temperature work ok then the CVR is probably ok. If they are also intermittent it's likely the CVR or maybe the printed circuit or it's connector. You can test the wiring by disconnecting the sender at the gas tank and shorting the wire to chassis for a moment (with key on). If the fuel needle deflects towards full, then the wiring is ok (DO THIS QUICKLY - LEAVING IT SHORTED TOO LONG CAN DAMAGE YOUR GAUGE). Keep in mind a loose wire may test ok one day, then rattle loose and test bad another day. Put an ohm meter between the chassis and the sender post on the gas tank - you should measure some resistance, if it measures open circuit then your sender is bad. The floats can also leak and sink in the tank but this won't be intermittent - it will be permanently on "E" when that happens. It's possible the crude sliding potentiometer on the sender may be corroded. Some emery cloth on the connector can't hurt either. Good luck! Quote Share this post Link to post Share on other sites
Mach1 Driver 560 Report post Posted May 3, 2018 The gauges are on page 2 of "A Real Schematic" in "How To" on this site. The sender should read 10 ohms on hi or 78 ohms at low. If you determine its not the wire and gauge then its probably best to take the sender out of the tank, clean it up and do a resistance check. The rheostat may not be making good contact throughout the travel of the float. Everyone I've read says its better to take the stock one out and refurb it than to get a repop. No one makes a replacement that matches the original resistance curve, making them inaccurate. Quote Share this post Link to post Share on other sites
Topless69GT 28 Report post Posted May 8, 2018 Thank you. It turned out to be the reproduction sending unit that was bad from the start. Quote Share this post Link to post Share on other sites
