The fuel gauge needle in my old Ed goes straight to the top, then collapses to the bottom and doesn’t move. I’ve cleaned the sender unit plug terminals on the top of the tank. But while writing this I remembered this problem may have reared its ugly head after I had some air-con work done behind the dash. The car has been sitting in the shed for about a decade, until my son said that he’d like to drive it.
I have to remove the instrument panel to repair the odo, so I was just thinking that maybe there is an earthing problem to the fuel gauge as well. I’ve seen here where other people have encountered a similar problem, but the post always seems to go dead without an answer being given. The question is, has anybody out there in the ether seen a similar thing with their fuel gauge and how have they fixed it?

Well I finally managed to undo the fuel tank locking ring to remove the pump and sender unit. My god, it was like picking up the tar baby. The rubber sleeve around the pump had tried to revert back to its original ingredients and unfortunately I just got in the way. My hands were coated in a thick,black,sticky bitumen-like gunk that was extremely difficult to clean off.
I found that if you just left all of the pieces alone for a while the coating would quickly dry like paint. The pivot point for the sender unit float arm had seized up and so the arm could not move at all. The unit is sitting on the bench with some degreaser on the pivot, soaking in over night. I think something stronger like thinners may be needed though.
I hotwired the pump, but it seems to be dead. The bottom of the tank has a thick,slimy,black coating over it that I suspect may have once been the components of the old fuel. I’ll have to clean it out before putting a new pump back in. I believe the fuel sender should come good if I can just free up the float arm pivot point without dismantling it. I’m sure the fine wires would easily break.
Fingers crossed.

The fuel sender float arm now moves freely after soaking the sender unit in a bucket of hot soapy water and moving the float arm back and forwards for awhile. I then repeated the process a couple of times when the water cooled. The lump of gunk that was stuck to the circuit board also finally washed away.
If suddenly your fuel gauge is reading erratic, then there’s a chance that the float arm is stuck solidly in one place like mine was. My gauge was actually playing up while I was using the car daily, not after sitting for years. So there we end the story of the dodgy fuel gauge. (famous last words).

so the gauge is now rock solid re readings then?.

Today I tested the fuel sender unit on the bench using a dmm, and I got a reading of around 13 up to 200 ohms. So none of the fine wires are broken and the arm moves by itself freely throughout its range.
I was wondering why the needle in the dash would go right to the top then drop back down to the stop though. Why didn’t it simply read at the position that it was stuck on. Maybe the big chunk of crud that was stuck on the circuit under the metal contact was insulating the contact and prevented a signal to the gauge.
I won’t know until I get a fuel pump and I also have to clean the bottom of the tank out.. But I really can’t see why it wouldn’t work once in the car.

I finally got around to trying the fuel sender unit in the car today. I plugged it in and moved the float arm by hand to different positions while the needle in the gauge showed the corresponding reading. Just like a new one. But I don’t think you can buy the e series fuel sender new anyway.
I did notice though that the au sender unit is a pretty good match and you can get them new. I tested my spare au sender unit with a dmm and the readings were different to the ed version though. But in a bind you could probably use the au one with a sender unit signal converter box and sync the sender to the gauge.