Scott Gardner wrote:
>
> > A fuel tank sender is a variable resistor. The uneven spacing of lines on
> > a guage is because the resistance output of the sender is not linear per
> > quantity of fuel in the tank.
> >
> > CTP
> >
> >
> > At 10:23 PM +0000 1/13/98, Scott Gardner wrote:
> > > My brother's BMW had the 1/4-tank marks spaced unevenly
> > >along the face of the gauge, but they were accurate. Perhaps this
> > >was to compensate for problems with the gauge?
> >
> Which begs the question, "Why aren't all cars done this way?". Is
> there a way that other automakers use to get linear output from the
> sender? I would think that this would be a pretty mature technology
> by now.
> Scott
If you dismantle a sender, you will see that the manufacturer has tried
to make it linear by wrapping the resistance wire on a former that
changes width along its length. The wider part of the former has more
wire to each turn hence more resistance. However we are not just talking
about linearity here, but max and min settings. I changed the sender on
the V8 and promptly ran out petrol when the gauge was still showing 1/8th tank.
The gauge is adjustable for both max and min via slots on the back of the case
by the terminal posts, they may be covered by cork plugs.
PaulH.
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