Series 3 Sender unit/ Fuel gauge issues

New gauge arrived yesterday, fingers and toes were crossed!

Part was guaranteed working so even though the contacts looked a little grimy I just thought i'd throw it in and see what happened. This time, the gauge went straight up to 1/2 full tank from both senders... I knew that wasn't right as my tank with the old sender was nearly empty and tank with new sender unit was full! So i took it back out and cleaned it up, along with the front lip and outside of the cluster housing just for fun. Upon re-installing it things are working and a difference can be seen in the levels when switching between the tanks THANK GOD, I was about to despair.

But I do have some final questions before i'm out of the woods! How do you go about calibrating these gauges? The Fuel and Water Temp gauges have fallen below their low point:


When everything was all working I decided to put the old gauge back in, just in case the extra cleaning I had done made the difference and the same issue prevailed just as before. So now I have a spare gauge that has trouble earthing, should I try to get it fixed or sell on cheap with a known issue?

Obligatory can of WD40 in the background there making an appearance. Maybe I should start charging for advertising with the amount of pictures I'm posting haha.

Cheers,
Nick

Good news that you're getting better readings off the new gauge!
I don't think these gauges are adjustable (unlike the thermal ones that have adjustment slots in the back). There are two resistors on the back of the gauge that are probably selected to calibrate the gauge in the factory, but I've never found any useful info about this and haven't had time to experiment!
It's odd that the needles have dropped so low - not seen this before - but as long as they are reading more or less correctly it shouldn't be a problem. You can check the max reading by shorting the sender to earth and the gauge should climb to just past the 'F' mark.

Unfortunately they are both reading max at about the 1/2 way mark... Meaning for the most part, needles are hiding under the covering. Frustrating thing is that I've spoken to Richfields and they reckon that re-calibrating them is possible, but more expensive then purchasing new ones. They reckoned that they would sell them for £30 a piece. Feel like I've been had!

Is it not possible to pop the pointer off and relocate as your full is only 1/2 way.