I seem to have got a problem with my fuel gauge on my GTM Libra with standard Metro tank and sender.
The fuel gauge goes straight of the top when the ignition is on it used to work just fine I asume this means the sensor wire is straight do to earth I was thinking if it could possibly be that the to of the sender is wet and thus causing it to go straight to earth it has previosly done the same thing but has always only done it for a few seconds but it has now been like it this time for sround a week.My next question if how do you get to the sender without dropping the tank down.
Thanks Matty.
Hopefully I can judge when I need to fill up.

Unfortunately you have to drop the tank

A lot of people have cut the alloy rad pipes just before the tank and joined them with hose to make tank removal that bit easier.

Other than that there is no easy way. I did consider cutting a hole inside the tub for access. I think with my maxitank it would have been do-able with 2 holes but in the end I left it alone.

When I bought my Libra kit many years ago, I realised that if a problem developed with the fuel sender unit it would mean dropping the tank, so I asked Paddy if it would be acceptable to cut a hole in the Tub to get at it. He advised against this as in his opinion it would weaken the Tub too much. The only way in is as Roger suggests.

Would I be right to think that the gauge/sender works by measuring the resistance across the fuel sender unit and that a low staight to earth reading would cause the gauge to go off the top.

If you put the earth side of the transmitter direct to earth the gauge should read full. Water temperature gauges do the same (but read 'Hot' rather than 'Full', of course )

Looks like I will be dropping out my tank,should of put a new sender in when I had the tank out to put the 1.8vvc in.

Everything's easy with hindsight....

Well, you can say that now!