Mystery Fuel Gauge

[Seaking]

Well this is very odd.. Its happened more than once this year where I would pull in for fuel, top right up to the gunnels and when I ride away, for the next 2 to 4 miles down the road, the gauge will read two to three bars down from full.. then slowly add bars until full bars are showing. I'll arrive at destination, 12 or 20 miles down the road, shut off the bike and then roll away after a while.. the fuel gauge shows 1/2 full bars.. but only 20 miles total run since fill up.. then the bars creep up to full or down one bar.

 

Something is sticking.. On a long round about right hand turn off the highway, with the bike leaning hard to the right side, the fuel gauge once again read much lower that it should have for the amount of distance travels but the bars didn't increase.

 

Its doesn't happen all the time, can't seem to pin it down to any specific conditions.. but oddly enough, my buddy with his 2008 does the same thing from time to time.. His bike did this often last summer but it cleared itself..

 

Any idea what we might start looking at to start trouble shooting this issue? 15 days to road trip, it's something I'd love to clear up..

 

Cheers

[LilBeaver]

The fuel sending unit is really (in my opinion) the only part that could be causing this behavior. It is easy enough to remove, clean, inspect and reinstall it even though it does require that you completely drain your tank.

 

It may be worth while to pull it out and take a look to see what may have collected on it and clean the varnished fuel off of it while you are there. ALSO, take that opportunity to take a really good look inside your tank to see if you've got some extra debris floating around.

 

Not that it would directly affect the fuel gauge/sending unit but you may as well check your vent hose while you are there; make sure that it is not obstructed anywhere.

 

Now, the fluctuations in the gauge while dealing with extended leans and such is not surprising, but the delay in showing 'full bars' after a fill up could possibly be related to something in the fuel affecting the buoyancy of the float on the sending unit. I sort of doubt this, but I wouldn't rule it out entirely.

 

Just a few thoughts.

[Flyinfool]

OK a couple of more ideas here.

Fuel level gauges almost always have some form of damping on them so that the display is not jumping around with every wave caused by motion of the bike.

This damping can be either mechanical on the sender itself or electrical most likely at the meter.

If the damping is mechanical at the sender, and caused by a buildup of dried fuel or other crud on the moving parts Then keeping the tank near full with some Seafoam in the gas may help to clean it up.

If the damping is electrical in nature, it will be a lot harder to locate since it is most likely a bad or weak component on a circuit board, The electrical possibility is a lot less likely to "fix" itself, where some crud could wear off and go away.

[CaptainJoe]

While your in there use some blue loctite on the screws to your gas cap....

 

Mine fell apart while riding on my 650 Vstar and its the same cap as the RSV... I also have to take the tank off, to get my parts...

[Seaking]

Looking through the manual all I can find is 'how to put it on' and fuel pump.. but haven't been able to find anything about the innards of the tank as to where the sensor might be at..

 

Its possible there is something mechanical in there sticking thus not allowing the smooth motion of the thingy'ma'bob..

 

Anyone know where to look? I'll toss in a fresh can of SeaFoam to see if that helps to clean things off as well..

 

Cheers

[BradT]

I shut down for gas and when I turned it back on I got a funny blinking on the fuel gauge. Pulled the sending unit out and there was a broken wire.

 

I think I can repair it but decided to replace it with new as they were only 60+ bucks.

 

Brad

[Seaking]

So it's accessed from UNDER the tank? Four bolts and everything comes out through the hole? Simple as that or is there a little more to it than that?

 

not hard to empty a tank of gas is it..

[Condor]

Yep I'd replace it. When you parked it reading full and then let it sit a while, come back, and it reads 1/2 full, you might have a leaking float. Shake the float and see if there's fuel inside... OR... the plug is corroded and resistence is marginal?? Just a guess??

[Seaking]

Yep I'd replace it. When you parked it reading full and then let it sit a while, come back, and it reads 1/2 full, you might have a leaking float. Shake the float and see if there's fuel inside... OR... the plug is corroded and resistence is marginal?? Just a guess??

 

 

Any guess to the cost replacement of these units?

 

Mine will read full after a bit so I don't think it's leaking but it's a good thought..

 

Cheers

[LilBeaver]

So it's accessed from UNDER the tank? Four bolts and everything comes out through the hole? Simple as that or is there a little more to it than that?

...

 

Yes, accessed from under the tank - When you flip the tank over you can't miss it. Yes, 4 small screws and it all comes out that tiny little hole. I found it a bit tricky to get it out though, it took A LOT of rotating and finagling; but be gentle and take your time you will eventually find the proper orientation. It really is that simple.

 

... the plug is corroded and resistence is marginal?? Just a guess??

This seems reasonable.

 

Any guess to the cost replacement of these units?

 

...

 

I picked mine up from Pinwall for $10+ S&H (which I think was around 12). New through partshark: $78.81+S&H, Yamaha OEM P/N 1D6-85752-00-00

[Seaking]

Super info.. many thanks.. if I'm going through all that trouble to pull one out I'll prefer to put in a new one.. last few things I got from Pinwall didn't work or were not as advertised, unfortunately.. and being 'electrical / electronic' there is no return.. sigh..

 

Cheers and thanks again

[LilBeaver]

Super info.. many thanks.. if I'm going through all that trouble to pull one out I'll prefer to put in a new one.. last few things I got from Pinwall didn't work or were not as advertised, unfortunately.. and being 'electrical / electronic' there is no return.. sigh..

 

Cheers and thanks again

 

That is a tough break or maybe I have just been lucky. I have only ordered a few things from them and each were as pictured/shown in their videos and functioned as they claimed they would. One was the handlebar radio controller and the other was the fuel sending unit. I really don't like to use them because of the shipping cost.

 

Anyways, there may be less expensive sources than partshark or maybe even if you investigate the different years of bikes; that price was from the 2010. Also, is your bike still under warranty? If I recall correctly it is a US bike but you have it in Canada. I wonder if you'd be able to work something out with a dealer next time you head back to the states.

 

Anyways, best of luck to ya!

[REDRIDER52]

before you pull tank check the connector under the black cover on tank dont ask how i know mine was doing funny things conector was loose

[BradT]

Any guess to the cost replacement of these units?

 

Yamaha dealers in Canada wanted 140 bucks or so plus the HST.

 

Yamaha Sprts plaza had them for under 70 bucks, Pioneer I think was 85 or so.

 

Tank does not need to be empty, but low. Four bolts and yes it comes out, but needs to be rotated a few times. Get a new gasket about 8 bucks but remember to put it on before installing. HAHA

 

http://www.yamahasportsplaza.com/

 

BRad

[Monty]

First thing I would do, is unplug the connector, spray some contact cleaner on the contacts, and plug/unplug it a few times, then put some dielectric grease on the contacts, and give it a try for a bit.

[Gary N.]

Had the same thing happen to mine. Pulled the connector apart, greased it up and it's been fine ever since.

[Seaking]

Yes, I'll certainly clean out the connector and check the vent and toss in the seafoam before pulling the sensor out..

 

Thanks again folks.. MUCH appreciated..

 

2006 bike out of warranty now anyway.. learning all this fun stuff is.. fun..

 

Cheers and safe riding..

[Dave77459]

I think this thread applies to me, so rather than starting a new one, I thought I'd tag on.

 

Yesterday on a ride, I filled up then ran about 20 miles and shut off. After an hour, we saddled back up. About a mile down the road, I noticed the low fuel indicator counting. On an RSTD, when it senses low fuel, a count up ODO starts, letting you know how many miles you've gone with low fuel.

 

I noticed it at F1.3, and was greatly puzzled. It sure seemed like when I was stopped, the tank was drained. I did a quick U-turn to head back to the nearest known gas station. Then I stopped and looked in the tank: it was still full.

 

Mentally shrugging, I did another U-turn and noticed that fuel was being added to the tank. It eventually indicated full again. After that, it operated normally.

 

Is this another example of the fuel sender problem? I've had my tank off so many times recently that I would not doubt the connection is wonky. I'll add some dialectric grease and make sure it is solid.

 

Whatchu think?

 

Dave

[LilBeaver]

I think this thread applies to me, so rather than starting a new one, I thought I'd tag on.

 

Yesterday on a ride, I filled up then ran about 20 miles and shut off. After an hour, we saddled back up. About a mile down the road, I noticed the low fuel indicator counting. On an RSTD, when it senses low fuel, a count up ODO starts, letting you know how many miles you've gone with low fuel.

 

I noticed it at F1.3, and was greatly puzzled. It sure seemed like when I was stopped, the tank was drained. I did a quick U-turn to head back to the nearest known gas station. Then I stopped and looked in the tank: it was still full.

 

Mentally shrugging, I did another U-turn and noticed that fuel was being added to the tank. It eventually indicated full again. After that, it operated normally.

 

Is this another example of the fuel sender problem? I've had my tank off so many times recently that I would not doubt the connection is wonky. I'll add some dialectric grease and make sure it is solid.

 

Whatchu think?

 

Dave

 

Dave:

 

The fuel sender unit is pretty straight forward (I have some pictures of it but they are on my other computer - I'll edit this post with pictures later) and from what you describe, a logical conclusion is that it simply got stuck. Personally, I would not worry about it. Maybe next time you have the tank off, drain it and pop out the sending unit to inspect and clean it.

The fuel sending unit has a float attached, to a rod, with contacts on it that move along a board with various contacts with varying resistance. As the float moves up or down (as the fuel level changes) the resistance of the circuit changes which is what the 'fuel gauge' is actually measuring.

Now, the tricky part is that the 'fuel trip meter' and the 'fuel gauge' itself are two separate circuit components. The fuel trip meter portion is actually a separate entity that is submerged in the fuel and is supposed to be activated when the fuel level drops below it. Impurities in the fuel, moisture bubble, air bubble, etc could cause a false read that would go away after the gauge cycles. Also, the 'fuel trip odometer' is supposed to reset (and disappear) when that component is submerged for 5.0 miles so it is possible that maybe it had switched to count up right before you stopped and you maybe didn't notice it until after you were driving again.

EDIT: After re-reading your original post, I see that you rode ~20 miles after the fill up then shut off. This renders my last point moot as it would NOT be left over from before your fill up. So, it is possible that your unit is on the fritz, but again, pulling it and giving it a decent inspection and cleaning may be in order... or at least wait to see if the symptoms are repeated at some point.

 

Again, if it were me, I would not worry about it unless it happened again. It may be enough to prompt using the "ON" selection instead of "RES" selection on the petcock (if you are one of those that relies on the fuel trip gauge instead of switching the petcock) but since it is a non-essential component of the bike that won't cause any problems if it fails, I would ride on and if it happens again, then worry about troubleshooting it.

 

Just my :2cents:

[Dave77459]

Again, if it were me, I would not worry about it unless it happened again. It may be enough to prompt using the "ON" selection instead of "RES" selection on the petcock (if you are one of those that relies on the fuel trip gauge instead of switching the petcock) but since it is a non-essential component of the bike that won't cause any problems if it fails, I would ride on and if it happens again, then worry about troubleshooting it.

 

Just my :2cents:

Hmmm, I am one of those who habitually runs on RES rather than ON. I think I'll use ON until I regain confidence that it was a fluke. Good idea!

 

It is also super easy to check the fuel sender plug connection.

 

Dave

[LilBeaver]

Hmmm, I am one of those who habitually runs on RES rather than ON. I think I'll use ON until I regain confidence that it was a fluke. Good idea!

 

It is also super easy to check the fuel sender plug connection.

 

Dave

 

That it is.

By 'remove, clean and inspect' I had been referring to the actual sending unit BUT popping off the cover to inspect the connector IS easy enough to do. When you have that off, if you have a multimeter you can actually check both the "fuel gauge" circuit and the "fuel trip meter" circuit. The procedure is outlined in the service manual.

Feel free to let me know if you have questions or need a hand with that.