Hello again. When we last visited I had discovered that the sender was very
flaky in the resistance it was sending out. So I dismantled it and cleaned
it up and it seems to work much better. It ranges from about 3 ohms in empty
to about 75 ohms at full which corresponds very nicely to the resistance
numbers Randall Young finds on his TR3 fuel gauges. So I hooked it back up
and the gauge flies way past full while sender in empty position -- and
travels back to half full when I pull the sender up to full position.
So I went back and made more measurements of the gauge itself. Here is what
I get measuring with resistors between the green/black sender lead and
ground:
200 Ohms: just above empty (barely)
100 Ohms: 1/4
68 Ohms: 1/3
34 Ohms: 2/3
This is not good. First, it is travelling in the opposite direction of my
sender (i.e. more resistance leading to empty instead of full), and looking
for a resistance range way beyond what my sender can provide. BTW - I
reversed leads to gauge and got same result. To make sure the gauge is
grounded I'm running a separate wire clipped between the mounting screw on
the gauge and a big fat ground.
My gauge is a Jaeger with BF 2301/00 on the top of its face.
Does anyone know what might be wrong?
Thanks again,
Dave Moag
62 TR3B
77 Spitfire
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