Something screwy with my fuel level sensor?

[Viking445]

Ok so I have an 89 320i frame with an M52 swap. I was driving home from work today and my gas gauge suddenly when to below E from about 1/4 tank. So i went to the gas station and filled it up. In Sicily you stay in your car while the attendant pumps the gas (so odd for me btw! lol). She only put 30 liters in a 63 liter tank and the needle shot from below E to 3/4 tank and she said it was full. It didn't climb to F just stuck at 3/4.

I've done some reading and there is a level sensor on the drivers side of the tank and a sensor on the fuel pump which is on the passenger side. What could be causing this odd behavior?

Thanks!!!

[dnguyen1963]

years of building up gunk inside the sender. Take it out and spray some carb fluid into the aluminum tube (there should be a few small holes on the side) then shake the floater up and down vigorously. Do this until there is no more brown/black specks coming out of the sender housing.

[EatsHondas]

My gas gauge used to jump around and act weird. Water had somehow gotten in the connector to the sender and caused weird readings. Dried it out, no problems since.

If problems persist, check the ground nut on the back of the gas gauge (remove instrument cluster).

[Viking445]

Ok so i know this was a year ago but i finally got around to cleaning the senders. First i did the drivers side. As stated along of black specks that felt like sand came out (rust maybe the small nut on the bottom was rusty). Then put it back in no difference. I looked in the tank and it was atleast 1/2 full but the gauge still read just above Empty.

So i did the passenger side sender. Same deal lots of black grit and stuff came out. Reinstalled it and turned the key and the gauge didn't budge from below Empty. So i took it back out and made sure the prongs were all good and that i hadn't damaged anything and then for shits and giggles hooked it up outside the tank and discovered the idiot light still worked but the needle did nothing as i rocked the sender back and forth.

Did i just break the passenger sender?

[Viking445]

ok update. I took the passenger sender back out one more time and and shoot it back and forth and rocked it all over and the gauge shot up to 1/4 and then back down but never above 1/4 tank. pretty the internals of the sender are messed up.