Fuel Gauge problem

[Adam2980]

I have an 82 XJ 1100 and on my intrument cluster, the fuel is not comming up. Normaly I would see four bars for a full tank, now it just says "FUEL" and shows no bars so I can not tell how much I have in the tank with out actualy looking in it. Any thoughs on what might be the problem and where to start looking?

On another note, I am thinking about redoing the wire harness. It has not been touched in 30 years and I think replacing it may solve some issues that are not the big, but they all add up. What I would like to know is how hard of a project would that be and where I might find the right harness for my bike.

I appreciate any thoughts and any help.

Adam

[TopCatGr58]

Hey there Adam,

Please see my reply to your flasher problem, you probably do NOT need to get a new harness, and you really can't get a NEW one anyways, they are all OLD used stock that is on Ebay, nobody makes replacement ones for our bikes anymore!

Have fun cleaning and greasing. BTW, does it still have the OEM glass fuseblock....if so, it's recommended to replace it with the newer style ATCO solid fuses and holders...see the For Sale Forum, Parts section, Parts and services by members sticky thread, scroll down, you'll see the fuseblock and connector set that is available for a decent price. I just sold the last one a couple of days ago, but also reordered another batch of 10, they should arrive in a day or so, then I'll be able to send them out.

T.C.

[SFerinTEXAS]

Sender

Either you have a manual or downloaded the graciously provided one from
http://www.ringler.us/family/mybike.html . test at the sending unit plug to the tank.If full will read close to the ohm full number. If it does then the wiring in the harness to the cluster is suspect, if not then pull the sender out of the tank. several solutions from there. Float came off, windindings on the rheostat in the sender crudded up and so forth.My idea on a first step.

[clcorbin]

The basic fuel gauge circuit is VERY simple. The fuel sender is just a potentiometer. Voltage is applied to one end and the current is regulated by the position of the sender, the highest current (most systems) is full and the lowest is empty.

At the other end, you have a resistor and a capacitor and a simple volt gauge (aka: the fuel gauge). The resistor and the capacitor are connected in parallel and the wire from the send connects to one end of the pair and the other end is grounded.

As the current flows through the pair, the capacitor is charged up. The amount it can be charged to is determined by the fuel sender. That resistor and the other resistor act as a voltage divider, so the voltage across the fuel gauge is highest when the resistance of the sender is lowest and visa-versa. A simple meter across that resistor just indicates the voltage across it, but the panel is marked in fuel level instead of volts!

The capacitor is simply there to "buffer" the voltage so the fuel gauge isn't swinging all over the place as the bike accelerates, brakes, goes up hill, goes down hill, etc.

All in all, a very simple circuit to trouble shoot and test IF you have the wiring diagram and a volt meter (or better yet, a decent DMM). Good luck!

[ViperRon]

The float assembly in my XS11 stuck as my tank sat empty for some time. After cleaning it worked fine. If your tank sat low or empty for some time there may be a chance the float stuck. measure it with a meter to make sure it moves you may just have a sticking float. I do agree with others here that all conectors and the fuse block in these bikes need attention but suggest you do them (all) at one time it will lessen the chance of creating problems.