My Wagon has the silvia dash in it and is running the R31 fuel tank. For some reason when i turn the ignition off the fuel gauge doesnt drop all the way down like most to empty. Could this be its getting power still or What ?? Help. Am handy with a solder and heatshrink but nutting out things like this isnt my strong point.

Does the guage stay at the same spot when the car is on to when its off, or does it just not drop all the way when off?
Does the guage read true, ie full when full empty when empty, etc?

Its a bit hard to really diagnose, but i would be looking for persistant power somewhere first.
After that, look for bad earths, or add eatra ones at the fuel tank and at the dash.

If thats not successful, the sender could be playing up. ie showing 1/2 full when empty or something like that.

After that, its a test light, multi meter and lots of paitence.

I just put 15 litres of fuel in my R31 tank yesterday and turned on the ignition ... my needle dropped on my silvia dash.... can they be wired backwards???? yes i did play with the plug on the r31 to try matching it to what i thought the silvia loom would need (wish i remembered which wires i moved)