Re: Dancing Fuel Gauge

Posted by HH56 On 2020/11/16 10:57:35
It is possible the instrument voltage regulator is faulty but the temp gauge also works off the same unit and even though reading low, should be doing a version of the same dance if regulator was acting up. To check the temp sender and gauge remove the wire and touch to ground just long enough to see if the temp gauge moves to hot. I really suspect the fuel sender is the cause of your fuel gauge issues.

The 73 ohms at empty is good but it should be around 10 when full and not 0 ohms. Unless your meter is not very accurate at low values then that reading on the full side is suspect. Even though it might test good out of the tank there have been many instances where a sender again proved to be faulty once back in normal operation.

The not going all the way back to empty is a puzzle. Assuming the gauge itself is working properly and does go to empty when the sender wire is disconnected or key is off, for it to stay at half full when the tank is not would indicate something in the tank is preventing the float from dropping or else there is something amiss inside the sender that is providing a fixed resistance value that is enough to keep the gauge reading even though the float has dropped past the half full level.

One other thing that many have found after tanks were removed and replaced is a poor ground between the tank and body can become an issue. The poor ground will also cause a dancing gauge but would not be responsible for it failing to go past half full. To completely rule out a ground issue you might drill a small hole in the excess metal at the center weld seam on one of the corners and attach a small wire to provide a solid ground connection between the tank and frame or body. Alternately, you could also figure out a way to attach a wire on the sender flange or retaining ring working thru your access hole.

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