Inaccurate Fuel Gauge?

Inaccurate Fuel Gauge?

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v8s4me

Original Poster:

7,254 posts

221 months

Friday 8th May 2020
quotequote all
Well most of them are!
This is the sender unit with the float in its lowest position and the arm of the rheostat at the end of its travel.

Now it would be reasonable to think that this would correspond to "Empty" on the gauge and try and set the float level from this starting point. However, the arm of the rheostat needs to be in this position before it has any effect on the gauge...

So this is the point which corresponds to "Empty" and it's from here you need to start experimenting with the the height of the float by bending the wire. In my case the wire needed quite a severe bend to get anything like a full range on the gauge...

So now my gauge has a wider range of reading rather than just going from 3/4 full straight to empty after about 75 miles.
When we can get out and about again I'll fill the tank and see what happens. I'm not expecting it to be accurate but slightly more accurate than barefaced lies would be nice. laugh

I'm not suggesting this will work for everyone but if you've had no luck so far why not give it a try?

magpies

5,131 posts

184 months

Monday 1st February 2021
quotequote all
This is from the Smiths Gauges web site:

a typical European standard would be 10 ohms at empty and 180 ohms at full for a fuel gauge/sender combination.


So you need to bend the operating arm to suit the position which gives those resistance readings which will be within the full range of sweep.

v8s4me

Original Poster:

7,254 posts

221 months

Monday 1st February 2021
quotequote all
But are they Smith's gauges? I'm not sure they are.

Fefeu52

198 posts

68 months

Tuesday 2nd February 2021
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I did this mod 2 years ago :

https://www.pistonheads.com/gassing/topic.asp?h=0&...

I'm really happy. Now the fuel gauge is pretty accurate... How painful it is to fill 50 litters in an S tank with the wrong vent !