Gas gauge problem on 2003 R1150RT?

[brianbmw]

Are there any known gas gauge issues with the R1150RT. My uncles gas guage as been reading inconsistently lately. When it's full it will sometimes read 6 bars, sometimes 4 bars, etc.

 

Brian

[snod]

There is a connector under the right side of the gas tank that gets dirty. Flat 5 wire connector as I recall. Take it apart, clean it, cover with dielectic grease, and reassemble. It will probably cure the flaky gauge issue. That same connector does low fuel, and the fuel pump.

[Dewayne Harkov]

I had the same issue and if cleaning the plug doesn't work, when you change the fuel filter the copper contacts of the rheostat on the end of the low fuel light arm can be cleaned with a Q-tip and Alcohol. You'll see a black residue on the q-tip. It fixed my erratic fuel gauge. Good luck.

[T__]

Brian, the one main issue that comes to mind is a plugging fuel tank vent system (actually the evap canister)..If that plugs up the tank vent so the tank can’t properly vent to atmosphere then the in-tank fuel pump can pump the tank pressure to negative pressure & suck the fuel gauge sender in on itself & crush it..

 

Does your uncle hear a woosh when opening the fuel tank cap,, or is the tank cap difficult to open after riding the bike a while? If so then suspect both an evap system plugging then the in-tank fuel sender partially crushed..

 

If all OK with the tank vent then look for poor wire connections (both gauge & ground) or old gasoline turned to varnish on the fuel sender ribbon causing erratic wiper contact..

 

 

Twisty

 

 

[GMC]

+1 with Twisty1:

This forum outlines all/most of the issues very nicely regarding the fuel gauge reading errors.

I recently attacked my gauge issue, which never showed totally full, but lingered on the last bar when there was still lots of gas. Had the tell-tale "whoosh" when opening gas cap.

 

Pulled it all apart per the great instructions found in several places on this forum, found a crushed float tube as suspected, straightened it, cleaned all connectors while I was in there, and its like new now.

[DrPaul]

I had the same issue and if cleaning the plug doesn't work, when you change the fuel filter the copper contacts of the rheostat on the end of the low fuel light arm can be cleaned with a Q-tip and Alcohol. You'll see a black residue on the q-tip. It fixed my erratic fuel gauge. Good luck.

IIRC, the sending unit mounted to the fuel pump/filter plate operates the low level light only. The RID bars are controlled by the tube-shaped sender Twisty has mentioned.

[moonbandito]

I have an '04 RT and I recently replaced the fuel filter, the 'U' hose, and the gasket o ring. After reassembly the low fuel light comes on at about 170 miles - even though there is more than the reserve in the fuel tank. The gauge itself is more accurate - but not when full. It never shows a full tank.

 

Is the remedy to clean the contacts of the rheostat on the end of the low fuel light arm with a Q-tip and Alcohol? Anybody have an image of what these rheostat contacts look like?

[dirtrider]

33 minutes ago, moonbandito said:

I have an '04 RT and I recently replaced the fuel filter, the 'U' hose, and the gasket o ring. After reassembly the low fuel light comes on at about 170 miles - even though there is more than the reserve in the fuel tank. The gauge itself is more accurate - but not when full. It never shows a full tank.

 

Is the remedy to clean the contacts of the rheostat on the end of the low fuel light arm with a Q-tip and Alcohol? Anybody have an image of what these rheostat contacts look like?

Evening  moonbandito

 

You have dug up a very old (2010) thread to tack your problem onto  (that is hijacking the old thread). 

 

You really should start your own thread about your problem (please do that in the future).

 

We will answer your question here this time-- 

 

On your current problem it is difficult to tell what your have as it could be either of 2 or more separate problems or a couple of  combined problems. 

 

The usual problems with the low fuel level reading incorrectly is either the float  starting to degrade or crumble, or the float arm getting bent at removal or reinstallation.

 

But a circuit resistance problem can also effect the low fuel sensor reading. 

 

With your main fuel gauge not reading full that can be a resistance issue, or a partially crushed float tube. 

 

You can try running some Techron concentrate  in your fuel as that can help clean up both the low fuel level sender & the thin resistor wires inside the float tube (probably won't correct your problems but easy thing to try first) 

 

Did you remove the float tube to check for damage?  If the float tube has a ding in the side of the tube (usually caused by the plastic fuel tank sucking in from a plugged evap canister or plugged tank vent) the float can't get past the ding so it can't read full.  

 

Or you could have a resistance problem in the gauge circuit between the sender tube & the dash gauge. This is usually at the tank to chassis harness plug but could also be in the pump pass through or in any part of the wire harness.  

 

Will the fuel gauge read full (or higher) with the key on but engine not running? If so this can point to a ground side resistance problem. 

 

You might also try cleaning the terminal pins in the tank harness connector to eliminate the possibility of resistance there.  

 

You can also try running a separate but parallel ground from the tank connector (brown) ground wire to the battery negative terminal. This improves the ground side continuity to ground. 

 

You have one of those things that you just need to work your way through until you eliminate the  problems (you now know what to look for).

 

 

[moonbandito]

Thanks. I will check these the next time I pull the tank.

[Keith S]

Thought I would add my thanks for this thread! This turned out to be my issue "You might also try cleaning the terminal pins in the tank harness connector to eliminate the possibility of resistance there." and back to normal gauge readings.

 

Keith S