Testing a fuel cell sending unit....

[blykins]

OK...here's what I found out.

I could measure resistance across the resistor...it was fine.

Still measuring across the resistor, I put the little arm back on and moved it around....it changed the resistance. Good.

I checked continuity from the resistor to the post. Good.

I checked continuity from the sender post to the ground post. It was short.

There was a fiber bushing on the top....but for some reason there wasn't one on the bottom of the flange....and it was shorting everything out.

But here's the thing.....When I insulated the bottom part and put it all back together, I'm getting really high resistance values.

The minimum I can get is 46 ohms. The max is 169. It corresponds to the positions on the resistor......Of course I can get as low as 5 and very high by just checking resistance across the resistor....so I guess the little arm is fallling within those values.

So the big question now is.....Do sending units have comparatively high resistance? For example, if I buy a 70-10 gauge and a 70-10 sender, does the sending unit actually have 10 ohms on the low side and 70 on the high side.....or is it a little higher to compensate for the length of wire it has to go through plus the gauge itself?

I guess what I'm getting at is....are these values correct for a 70-10 sender, or are they too high.....like high enough that they should be for another gauge?