I've got a stack fuel level guage in the 3dr, but can't get it to read above empty!

its the stepper motor one, but not the pro series.

I have tried the custom callibration where you start with an empty tank and fill it.

tank is pro alloy with a VDO sender but pro have ground off the numbers on it. iirc alex said it was a 90 ohm sender, but if I set the guage to that, or anything else it still doesn't work.

any ideas people?
cheers