Fuel Gauge

[Moses2]

Merry Christmas to all.
I have a fuel gauge that will read between 3 and 4 bars when the tank is full, and not go below 2 bars when I only have little more than a gallon left.
Last fill, when down to about a gallon left, the bar was flashing after I filled the tank , and then resumed 2-3 bars for the trip home.
Is there a thread someone can point me to for troubleshoot/repair. I've been resetting the trip meter for a fuel gauge.

 

[Gus1300]

Best I can point to is page 22-18 in my 2003-2005 Service Manual that talks about Fuel Level System troubleshooting procedures. The first step is if ALL FUEL SEGMENTS BLINK and "--.-" BLINKS CONTINUOUSLY so I don't think that would apply here based on your description. The next sections discuss Fuel Level Sensor Inspection (resides in the upper tank on those years, possibly stuck, but I wouldn't think as new as your bike is it would be?), Fuel Meter Inspection (verifying that all segments function properly, possibly your problem), checking the Fuel Reserve Sensor Ground (not sure if a bad ground would cause what you're describing or cause the level to not function at all but possibly worth checking) and Voltage, and a Continuity Inspection.

Do you have a service manual for your year that you can look at to see if it has a similar procedure for what you're experiencing?

As a backup in case your trip meter ever resets due to low voltage, you may want to also note the total miles when refilling and use both as the fuel 'gauge' until you fix the indicator problem. Don't ask me how I know that this is a very heavy bike when trying to push it to a refueling point!

 

[97rr]

Merry Christmas to all.
I have a fuel gauge that will read between 3 and 4 bars when the tank is full, and not go below 2 bars when I only have little more than a gallon left.
Last fill, when down to about a gallon left, the bar was flashing after I filled the tank , and then resumed 2-3 bars for the trip home.
Is there a thread someone can point me to for troubleshoot/repair. I've been resetting the trip meter for a fuel gauge.

I had a similar issue. The cause was a dirty in-tank fuel gauge. the culprit was the use of ethanol in the fuel system which left a residue of crap behind.

 

[jfheath]

Merry Christmas.

It sounds like the lower tank gauge may be ok. The guage goes to 2 bars when there is very little fuel in the upper tank, and begins to flash when the fuel drops below the sensor in the lower tank - about 5 litres left. So it may be the sensor in the upper tank is faulty.

On my bike the last 3 segments indicate very roughly 45 - 50 miles of fuel left per segment

I had a similar issue. The cause was a dirty in-tank fuel gauge. the culprit was the use of ethanol in the fuel system which left a residue of crap behind.

..... so how did you fix that @97rr ? Did a fuel cleaner additive sort it out or were you able to clean it in place or remove it and clean it, or did it requite a complete new unit ?

 

[97rr]

Merry Christmas.

It sounds like the lower tank gauge may be ok. The guage goes to 2 bars when there is very little fuel in the upper tank, and begins to flash when the fuel drops below the sensor in the lower tank - about 5 litres left. So it may be the sensor in the upper tank is faulty.

On my bike the last 3 segments indicate very roughly 45 - 50 miles of fuel left per segment



..... so how did you fix that @07rr ? Did a fuel cleaner additive sort it out or were you able to clean it in place or remove it and clean it, or did it requite a complete new unit ?

Cleaner helped a bit. But ultimately I had to remove it and put a brush to it. A new unit was not required

 

[Moses2]

Best I can point to is page 22-18 in my 2003-2005 Service Manual that talks about Fuel Level System troubleshooting procedures. The first step is if ALL FUEL SEGMENTS BLINK and "--.-" BLINKS CONTINUOUSLY so I don't think that would apply here based on your description. The next sections discuss Fuel Level Sensor Inspection (resides in the upper tank on those years, possibly stuck, but I wouldn't think as new as your bike is it would be?), Fuel Meter Inspection (verifying that all segments function properly, possibly your problem), checking the Fuel Reserve Sensor Ground (not sure if a bad ground would cause what you're describing or cause the level to not function at all but possibly worth checking) and Voltage, and a Continuity Inspection.

Do you have a service manual for your year that you can look at to see if it has a similar procedure for what you're experiencing?

As a backup in case your trip meter ever resets due to low voltage, you may want to also note the total miles when refilling and use both as the fuel 'gauge' until you fix the indicator problem. Don't ask me how I know that this is a very heavy bike when trying to push it to a refueling point!

Thanks Gus 1300. I have the manual open, at 22 - 18. I will go through some of these steps.

 

[SMSW]

IIRC, someone here fixed his fuel gauge - well, actually the sensor. Again, I remember it being the lower tank unit, and the sensing device is nothing more than a thermistor. He found one - probably at a large electronics house like Newark Electronics - and replaced the old one with new. This might take electronics expertise, or more likely, a confident 'I'll try that and see what happens'.

A warning - I'm going from memory here, and some or all of what I remember might be wrong.

 

[Moses2]

IIRC, someone here fixed his fuel gauge - well, actually the sensor. Again, I remember it being the lower tank unit, and the sensing device is nothing more than a thermistor. He found one - probably at a large electronics house like Newark Electronics - and replaced the old one with new. This might take electronics expertise, or more likely, a confident 'I'll try that and see what happens'.

A warning - I'm going from memory here, and some or all of what I remember might be wrong.

I'm going to drain and remove the tank today, with the 'I'll try..." , and keep a white courtesy phone nearby.

 

[Igofar]

I'm going to drain and remove the tank today, with the 'I'll try..." , and keep a white courtesy phone nearby.

Be VERY careful with the lower fuel tank if you remove the fuel pump assembly, as it is easily damaged by bending the sealing surface (think paper thin edge).
These pictures (not mine) show which line you need to remove to drain the upper tank.
If you try and do the "brush the corrosion off" be sure you use a gentle brass brush, and not a stainless steel one or you'll damage stuff.

 

[Moses2]

Be VERY careful with the lower fuel tank if you remove the fuel pump assembly, as it is easily damaged by bending the sealing surface (think paper thin edge).
These pictures (not mine) show which line you need to remove to drain the upper tank.
If you try and do the "brush the corrosion off" be sure you use a gentle brass brush, and not a stainless steel one or you'll damage stuff.

Thank you Igofar.

 

[klaproth]

My gauge used to get down to about 3-4 bars, and just sit there-then , after another 100-150 miles, would suddenly go to the flashing bar. I ended up taking the upper tank fuel sensor out, and cleaning it with an abrasive eraser, which fixed it right up.
This can be done with the upper tank on the bike, but I wanted to replace the tube going from top tank to bottom tank at the same time, so took it all the way off. You’ll probably want to replace the seal for the fuel level sensor, although mine looked just fine. I had about 25k miles on it at the time.
The area to clean is the “bars” that the float arm sweeps across . Mine was coated with schmutz, and cleaned up easily.

Good Luck!

 

[Moses2]

My gauge used to get down to about 3-4 bars, and just sit there-then , after another 100-150 miles, would suddenly go to the flashing bar. I ended up taking the upper tank fuel sensor out, and cleaning it with an abrasive eraser, which fixed it right up.
This can be done with the upper tank on the bike, but I wanted to replace the tube going from top tank to bottom tank at the same time, so took it all the way off. You’ll probably want to replace the seal for the fuel level sensor, although mine looked just fine. I had about 25k miles on it at the time.
The area to clean is the “bars” that the float arm sweeps across . Mine was coated with schmutz, and cleaned up easily.

Good Luck!

Thanks klaproth. I'll be taking the upper fuel sensor out tomorrow for inspection. There's alot of firsts here for me, so I'll be consulting the manual on how to remove the sensor. Will post some pics as to what I've found, chatting on the white courtesy phone, and maybe it'll help someone who searches 'fuel gauge' here, with my new to me experiences.
Like you, I wanted to replace the flow hose anyway, so I removed the tank.
More to follow.

 

[Moses2]

Hi all. While removing the left side panel to access TB2, I noticed it wasn't completely engaged (tab was not in the keeper) and was almost certain that this was the cause of the gauge inaccuracy. Removing the tank, I checked the sensor there, and it was clean. I touched it up with some open cell abrasive pad, just because. Feeling confident, I put things back together, gas back in the tank. Two bars on the gauge. Filled the tank completely, still 2 bars. A recap- earlier this year, the gauge would reach 3 or 4 bars, and go down to 2 (I can't remember if it ever went to 1) then I'd refuel. Recently, I ran the tank down to where I thought about a gallon was left, going by my tripmeter. Filled it up, and for the first time I got a flashing gauge when i started it up, which then again went to 2 bars as I rode on. So, onward.

 

[Sadlsor]

This is not something I anticipate needing to do for quite some time, but I appreciate your updates to add to my growing, internal personal database of all things ST1300.
If I could just find a remedy for my increasing cerebral flatulence, my database would be better preserved.

 

[Moses2]

This is not something I anticipate needing to do for quite some time, but I appreciate your updates to add to my growing, internal personal database of all things ST1300.
If I could just find a remedy for my increasing cerebral flatulence, my database would be better preserved.

Ha! Sadlsore I admire your transparency! Well, I paid tooo much for a PA, and although it has appears to be in good shape for the most part, I am committed to complete any repairs that are apparent, and all maintenance. I just want the bike to be in good repair if i decide to sell or keep. Thanks for the smile.

 

[Moses2]

Before I remove the tank again, I went back again to page 22 - 18 to look at fuel level system troubleshooting. This section starts off with all fuel segments blink and then it has some other blinks continuously. I filled the bike up yesterday thinking that would bring me off of the two bar reading on my gauge, (which it didnt) and decided now to go to step 2 and take an ohm reading at the fuel level sensor connector. Bad sensor?

 

[ishoottrap]

I just fixed my upper sending unit. Took it out, clean as can be, electrically open between connector pins. Traced it to no connection between the rivet bodies and the tabs where the wires that actually go to the wiper/segments are soldered. Cleaned it with CRC electronic parts cleaner, scraped the edges of the rivet heads and tabs until shiny right against the head then used a sharp awl to upset a little brass in both directions (tab into head, head into tab) around each head. Well see how it goes...

-Scot

 

[cdnemsguy]

Before I remove the tank again, I went back again to page 22 - 18 to look at fuel level system troubleshooting. This section starts off with all fuel segments blink and then it has some other blinks continuously. I filled the bike up yesterday thinking that would bring me off of the two bar reading on my gauge, (which it didnt) and decided now to go to step 2 and take an ohm reading at the fuel level sensor connector. Bad sensor?

And??? I would assume it was changed and that did the trick? This is like the last 3 pages are ripped out of a good novel... and yes, I would think that sensor was bad.