My fuel gauge $u(#$!

[madmax-im]

Well I generally go by the odometer for estimating when to refuel on my '82 XJ1100...My computer controlled LCD dash is way off.I can fill my gastank to the brim and have the bar gauge read full (4 bars).Riding down the road less than 5 miles from the gas station and already the bar gauge is down to 3 bars.By the time I have actually used 1 gallon..the bar gauge says I only have 1/2 tank eft...ok so the freaking thing aint working right...what can I do?Or is it the gauge never was all that accurate to begin with?IIRC it did work correctly at one point ....

[barberad]

Mine was doing the same thing until one day about a month ago when I got a floaty noise from somewhere around the inside of the gas tank I'll add that to the list of "small" things I'll have to fix. It was hard to retrain myself to use the odometer to know when to fill up again. Still not sure if my fuel is "on" or in "reserve"'yet either.

[madmax-im]

Originally posted by barberad
Mine was doing the same thing until one day about a month ago when I got a floaty noise from somewhere around the inside of the gas tank I'll add that to the list of "small" things I'll have to fix. It was hard to retrain myself to use the odometer to know when to fill up again. Still not sure if my fuel is "on" or in "reserve"'yet either.

AS for knowing when you're on reserve...with the petcocks in the on position and operating the bike...you simply wait 'til the bike starts stuttering under any throttle...then switch the petcocks to RES. and go find the next gas station

[barberad]

Ooooh...the way it is now, my LCD gage goes from full to empty by the time the bike finishes it's self test...not very good fuel efficiancy

[randy]

On the standards, we have about a gallon in reserve, specials / XJ's must have something near that? Not really a cause for concern, even if you're getting as low as 20MPG.

[blue giant]

Ben,
I have to admit mine is fairly accurate, so far. I remember reading the in the manual somewhere what voltage or resistance that you can measure to test the operation of the float. I'll have to scoot out to the garage to look it up.

Cheers,

Paul

[madmax-im]

Originally posted by randy
On the standards, we have about a gallon in reserve, specials / XJ's must have something near that? Not really a cause for concern, even if you're getting as low as 20MPG.

Randy...actually I think its more like a 1/2 gallon in reserve.

[blue giant]

Ben,

From my Factory XJ Shop Manual. Test resistance from sending unit (black and green wires from tank)

Full should read 20 ohms

Half should read 160-180 ohms

Empty should read 300-330 ohms

HTH

Paul

[madmax-im]

Originally posted by blue giant
Ben,
I have to admit mine is fairly accurate, so far. I remember reading the in the manual somewhere what voltage or resistance that you can measure to test the operation of the float. I'll have to scoot out to the garage to look it up.

Cheers,

Paul

See? I knew your XJ was better than mine...LOL I'll bet this one aint in the tech tips

[madmax-im]

Originally posted by blue giant
Ben,

From my Factory XJ Shop Manual. Test resistance from sending unit (black and green wires from tank)

Full should read 20 ohms

Half should read 160-180 ohms

Empty should read 300-330 ohms

HTH

Paul

Thanks Paul...I'll be checking that out...dont know if the unit in the tank needs to be replaced or not...Anybody ever replace one?

[cruiser]

Unit is easy to replace but hard to find one to replace it with.

My XJ starts reading bad about once a year. I run the fuel low or drain the tank and take the tank off, turn it upside down and remove 4 screws that fasten the unit to gas tank. The gasket is rubber so you can re-use it. Pull out the float assembly and you can carefully remove the metal cover over the resistance components and clean the resistance wire and contact arm with electrical contact cleaner and toothbrush GENTELY.
I seem to always have a buildup of fine almost powdery substance built up on the resistance wire. Always wondered if it has something to do with the ethanol fuel in Minnesota?

The other problem on XJ fuel gauge is the float has a tendency to slide down the arm because the fastener that holds it in place is not gripping the float arm.

I have run mine down till the fuel warning light comes on and have little under a gallon left in tank.

[madmax-im]

Thanks Cruiser..good info