Gas gauge puzzle

[Lifeguard]

I know I know the whole gas gauge doesn't work thing has been talked about forever. But I have tried everything to get my gas gauge to read accurately and consistently. I have 2 roadstars so I've pulled the dash panels on both and switched them and I get the same problem on the same bike no matter which dash gauge I use. I've cleaned with electronic cleaner the contacts for the small green wire connector at the base of the tank I've also cleaned the connectors at the speedo gauge panel. And so because I tried to switch the dashes and I got the same problem on the same bike with a fully functioning gas gauge my cage my guess is it's got to be the wiring. And no it's not the sending unit because I've already replaced that and it has been installed properly so it should be reading accurately consistently it doesn't matter if the tank is half full half empty full or full empty I still have the same problem. So I'm guessing it's gotta be the wiring and if it's the wiring what the heck could have happened just all of the sudden with nothing else going on as far as me gaining access to the wires or changing them or doing anything.

So my bike is at 1999 and it's worked perfectly fine up until about a month ago nothing nothing's changed I haven't done anything to it haven't done anything to the gages the wiring nothing nothing.

So having said that it is sometimes working sometimes pagging the needle all the way to the right and then sometimes just not working at all on hot days it seems to work a little more consistently than cold days and I don't know what's going on it's driving me crazy.

And no it's not because the needle is sticking on the paint that is deteriorated on the stop pegs because years ago I opened it up and put little plastic guards over those used for earring posts from my wife's pierced earring.

So any suggestions on what I could do next would be helpful thanks

[Shores]

Have you ever got an accurate reading since you changed the sending unit?

[Lifeguard]

Yes I do at times. When it is accurate is when it has been either full tank to about half. And it fluctuates from fully pegged to nothing. When it gets pegged it does show that the gas is being consumed and so it reading a change in the fuel level as it should just at the wrong level.

[Shores]

If it isn't consistently accurate then I wouldn't assume the sending unit is working correctly. Sounds exactly like my sending unit was behaving when it was bad.

[Lifeguard]

Well accept that is a brand new unit I installed which resulted in no change in the gauge behavior. That's what's got me puzzled.

[Tcontrol]

So you swapped gauge clusters…. Have you swapped gas tanks?…. Does problem follow the tank?….
you could always remove the “new” sending unit… plug it in the harness… and manually move it up and down… you might find a dead spot on the “new” sending unit….
these tests may further isolate the problem…

(assuming bad wiring may be a valid conclusion but these tests may eliminate all doubt ..)

[Lifeguard]

Good suggestions and I will do those tomorrow and see what I get. Thanks

[Brad_G]

Mine is an '08 and looking at the schematic for mine (and I assume yours is similar) it would appear there is power from the meter (gauge assembly) through the sending unit to ground.

Are there any other oddities besides the fuel gauge? The service manual has specs for testing the sending unit. While it seems unlikely from your description it would still be something worth testing again. I wish I could tell you where the harness grounds but I don't know. But that would be my next suspect area. Inconsistent electrical gremlins will drive you to drink.

[Lifeguard]

Yep that's the truth. Not a single other issue with anything. Everything works fine and I have tried to male sure by testing all lights horns other gauges but they all consistently work fine. Just the has gauge suddenly not working right.

[p birk]

My experience has been attributed to the variable resistance contact design between the float and it’s base.take a gander at the assembly just inside the tank. Observe the contacts changing as the float side contacts move against it’s solid to tank counterpart. I’ve seen the copper? feelers degrade and vanish. I assumed it was due to crap in the fuel. I’ve been able to gently adjust’ the fingers side extending the usefulness of a poor design. I just tossed my float 2 days ago, let me go see….

[p birk]

[roadiemort]

https://www.watelectronics.com/what-...ing%20constant.

[Brad_G]

Seeing this post reminds me of something I copied and kept for future reference. There was someone on the Delphi forums for Road Stars that posted up how he took apart his sending unit and fixed it. A couple posts down someone used a spring from a pen to fix the broken contacts. Unfortunately there are no pics.

If the link doesn't work I can past the text. But I'd rather keep it in context with the original thread.

Delphi Forum - fuel sender fix

It also appears we've been down this path here a couple years back.

https://www.roadstarclinic.com/forum...nit-adjustment

[Duke]

One thing to check is the retaining spring nut on the float pivot. If it is loose, it can cause the contacts to not be seated tightly. All you would have to do is press the spring nut in a little more.

[p birk]

Excellent first move!