FUEL GAUGE PUZZLE...HELP

[anastasio]

greetings group.

I have a puzzling scenario with my fuel gauge , it shows empty even though it has gas. but when its empty , the reserve light does light up.

I had it running until it ran out of gas, with the reserve light on, just to be sure it was not a short. when it died , I poured 5 liters on it, and the gas gauge did not move, but the reserve light turned OFF.

plase help, if anyone has had this situation.

sorry it a 1982 model 323 alpina c1 2.3

besr regards

Anastasio

[uwbuurman]

So, it must be in the gauge, since you get a signal to the light. Tried taking the gauge out of the dashboard?

[Jeroen]

iirc the reserve light and the gauge are separately wired signals, so you could have a bad connection on the gauge wire. Don't have a wiring diagram on hand but should be easy to find. I'd start by removing the cover underneath the rear seat to check the connector that goes on top of the sender that is part of the fuel pick up ass'y.

Next up would be checking the connector behind the instument cluster (fuel gauge side) or remove the cluster for checking the wiring and gauge itself.

[anastasio]

Wow, thanks for the super quick response, I will do that this evening, and check and see where is the fault

thanks so much

Anastasio

[Jeroen]

Keep us posted on what you find!

[anastasio]

Ok, so here is what I found, I unplugged the connector at the fuel sender in the gas tank, and tried with a jumper wire, if i jumped between common and one terminal, my fuel gauge jumps to full tank, and if I touch common and the other terminal, , the fuel gauge stays at empty, and the reserve light lights up.

I took the sender out of the tank, and dissasembled it , and there are supposed to be three wires going from the top, to the bottom, two of these wires are gone, there is only one left, and it is the reserve contact.

It will be a chore to try and install two wires where the other two were, but I guess I´ll have to give it a try, it really looks delicate though, I hope this can be done.

I hope someone in here has donde this before, and could help out, if not, I´ll just try to wing it .

the wires should be super thin....as thin as hair, I suspect if they are any thicker, the float will not slide, or the resistance will be way off....I dont really mind if the gauge is not precise, I can live with that, but I cant live with a non working gas gauge.

wish me luck

[Jeroen]

The only way to get this to work reliably is to fit a different level sender assembly, new will be expensive so I'd try to find a decent used example.

[anastasio]

Well. I have a semi working gas gauge, I had to find the thinest titanium wire, it is barely visible, I pulled it from an old mercedes float, Installed the wires, and tested, it didn´t have the right resistance, it should be between 3 and 95 ohms, and all I got were between 40 and 90 ohms.

as it is virtually impossible for me to get more wire, or a different thickness ( I dont know how to measure wire thicknes, I just went ahead, and left this like that.

it would show a full tank, even if it was half, and at almost half, it would go into reserve, and the reserve light would light up.

this was not a great scenario, so what I did, is I soldered a resistor 33 ohms, and now the gauge will never go into full tank ( sorry ), but it WILL, work, from half down, all the way into reserve.

I figured this was better than nothing, and that worriyng about running out of gas, at least this way, I will most likelly keep it full, or close to full, and at half a tank, I will have more than enough range to find a comfortable gas station.

anyway, sorry for the long write up.

best wishes

anastasio

[Jeroen]

and keep searching for a used example!

[ceaston85]

Hey anastasio did u ever solve this problem? I had same issue and ended up finding a new one in a shop in California. I replaced the sender but now my fuel gauge doesn’t quite work. It moves a few mm up when contact is on but that’s as far as it goes. I’m starting to think it’s the fuel gauge itself in the cluster.

[ceaston85]

I jumpered The 3-cable bundle that goes to the fuel sender. I junpered it both ways and the fuel gauge and the empty light both worked. I pulled out my brand new fuel sender and realize the fuel gauge wasn’t moving as I was forcing the plunger to move with gravity. Pulled it apart and one side of the float was not making proper contact with one of the wires. Adjusted that and fixed my issue. I should have known better to check the functionality of a 38 year old “new” part first.

[TaylorGoesFast]

I have a sending unit that works if you want to buy one. Just need to find where I put it.

edit: Oh, it seems you may have fixed it? Congrats !

[Jeroen]

Great news!!!!

[anastasio]

I´m interested in your fuel gauge...mine works but not perfect.

so please send me a PM, and lets do it.

Best regards

Anastasio

[anastasio]

I have a sending unit that works if you want to buy one. Just need to find where I put it.

edit: Oh, it seems you may have fixed it? Congrats !

I do want it Taylor....please let me know

Anastasio