Does this sound about right for a fuel level sender?

[davepl]

When brown wire is grounded I get a reading of about 1/8 tank UNDER empty.
When brown wire is connected to close-to-empty tank sender, reads -just- under empty.
When brown wire is disconnect from everything it goes to about 3 o'clock (1/2 tank past full)

I hooked it up to 100 ohm resistor (no combos to make a 90) and it read about 1/8 tank OVER full.

With two 47s (84 ohms) however it still reads that same amount (1/8 overfull).

10 ohms puts me just over empty.

So it seems I have about a 5-75 ohm range from empty to full. Is this typical or should I expect the gauge to be more accurate? If it were perfect 0 would be empty and 90 ohms would be full, but its not quite like that.