OK, I went out to the shop, and measured not one, but two Lark gauges. From a '63, I think. Temp gauge, sender to ground = 430 ohms, ign to ground = 238 ohms, sender to ign = 191 ohms. Measured the fuel gauge, too, and got exactly the same values. Exactly. Meaning the manufacturing tolerances on those things has to be on the order of 0.5%, or better.
I measured the same sending unit I used to test the gauge I sent to Jim, and it reads about 3.48 k ohms (3480 ohms). But it was drifting downward all the time I held the meter probes on it; probably warming in my hand. I would expect the sending unit to be very non-linear until it reaches the resistance range useful for the dash unit.
Hope this helps.
I measured the same sending unit I used to test the gauge I sent to Jim, and it reads about 3.48 k ohms (3480 ohms). But it was drifting downward all the time I held the meter probes on it; probably warming in my hand. I would expect the sending unit to be very non-linear until it reaches the resistance range useful for the dash unit.
Hope this helps.
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