Fuel Gauge Indicating full in error

[raymor]

Anyone had any problems relating to the fuel gauge? Mine took a fit over the weekend on a long drive down to Dumfries and now reads right off the scale. Must have a had a fit at the 28mpg average.....

I'm assuming that it's giving full scale deflection on the meter. Is FSD @ 0v or 12v ?

If that is the case, I'm hoping it's a open or shortcircuit rather than a defunct sender......

Any info would be much appreciated

thanks.

Raymond

[Stick Insect]

Ray, don't know if it's anything to do with it but there is a link on the www.20v.org site. It talks about re-calibrating the tank level on empty, may have had something to do with that.

I will try to find the fuel tank sender to see if it is resistance on empty or full.

David

[GandalfS6]

A friend of mine had this problem with his Passat and I had it with an A6 .... as a result of bad fuel! We had both used BP - after 2 tanks of Shell the guages started working again. I don't have a technical explanation for this though. Try a tank of different fuel and see if it goes away?

[horvathg]

Hear this.

My V6 coupe had the same, and it turned out that there is a faulty cold soldering on the printed circuit of the gauge board back with a bad connection ot the gauge supply voltage regulating diode. But since this connection supplies the water temp gauge aswell, the water temp gauge was cheating, too. Gauge board removed, soldering corrected, gauges OK since.


Cheers

[raymor]

Eventually got round to taking the instrument cluster out. Not good news, not fatal, but not good.

The gauge operates on a bi-metallic strip with a coil wound round it. So when the ignition is switched on, the strip heats up and gradually finds its way to the correct fuel level (hence the S2 slow rising fuel gauge).

Mine for some reason overheated and burnt itself onto the plastic backing, causing the gauge to vary wildly and then disconnect from the needle. I manged to gingerly pull the embedded hot wire from the plastic backing intact. The gauge is now up and working but will need to be re-calibrated.

Thanks for the link David, the tank now only shows half full, so I can recalibrate this weekend

cheers,
Raymond

[Stick Insect]

Originally posted by raymor
Thanks for the link David, the tank now only shows half full, so I can recalibrate this weekend

It depends if you are a pessimist or an optimist, whether it is half full or half empty!

Glad to be of help.

David