[TR] Fuel gauge

terryrs at comcast.net terryrs at comcast.net
Thu Aug 20 15:21:45 MDT 2015


So, the fuel guage works when I fill the tank.  Registers full.  Then, right about 3/4ths of a tank left, it wobbles, then drops to zero. 

Voltage at the sending unit is 12 in and a bit over 4 out.  Voltage at the gauge is the same.  Both measurements at the 3/4ths level.

I would guess that the sending unit is simply a variable resister, somewhat like the heater fan switch.  I would think that the resistance wire that the float rides on might be broken at that one particular point.  ...Except I'm getting 4 volts being sent to the gauge.

Am I right that the gauge is faulty?  I don't understand gauges, and why they might malfunction at one particular reading (and all subsequent until the gas tank is empty).

Thoughts?

Terry Smith, '59 TR3A
New Hampshire


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