2013 RT LTD - analog fuel gauge - accuracy - NOT !

[srwilli]

To date my 2012 RT limited fuel gauge has worked (still bounces) with fairly good accuracy. I usually fill after 150 miles, the gauge shows between 1/2 and 1/4. I am curious has anyone replaced the gauge with an aftermarket, and does it work any better than the standard gauge?


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[2manycars]

The digital gauge works, but once it hits 1/2 full (or empty depending on whether you are a pessimist or optimist), it drops to empty very quickly. I usually get overly optimistic when I have gone over 100 miles to the 1/2 way mark, but then 40 miles later the fuel light comes on. I guess the best answer is to figure on filling at around 130 miles or so.

The digital gauge is better than the analogue, but i wish it had a more even fuel level drop.

[NancysToy]

Lots of vehicles lack a linear fuel gauge response. It takes a pretty sophisticated sending unit and gauge programming to provide a linear response. It also helps to have an evenly shaped fuel tank, which contains the same volume for every inch of height. The eneven response is more evident in a motorcycle tank, due to its small volume. Most gauges I have seen drop faster in the lower half.

[Jeriatric]

BRP's latest update for the analog fuel gauge works very well. If you want to stay with the analog gauges. Have the update done. It's painless.

[diesel-dawg]

BRP's latest update for the analog fuel gauge works very well. If you want to stay with the analog gauges. Have the update done. It's painless.

I just had my 600 miles service done on my 2013 RT Ltd. They did not mention any updates that were available.

[Jeriatric]

I just had my 600 miles service done on my 2013 RT Ltd. They did not mention any updates that were available.

The update was to cure the bouncing fuel gauge issue(12's and back). It included a BUD's update and replacement of the gauge itself. I would think,(but do not know) the 13's came equipped with the change.

[NancysToy]

Scotty I do have to disagree.
It doesn't take much sophistication to map a linear response to a known gas tank configuration in 10 steps of resolution.
A look up table is all that it would take.
The ohmic value of the sender is correlated to a known amount of fuel.

The problem generally lies in the sender. As the float moves attached to the end of an arm, the wiper moves in an arc along the sender coil. As the fuel drops about 1/4, the change in ohms is about 1/5 the total range. Same for the next fourth of the level. The ohm change then begins to increase in proportion to the range over the remainder of the level change, and as the level drops the last fourth, the ohm value changes about 2/5 of the total range. The values do vary depeding on how the sender is constructed, but it is a matter of geometry and how the float moves in relationship to the curved resistance coil. Adding logic to the circuit would allow correction, but few fuel gauges operate that way. They are generally just simple electrical circuits. Safer than the old Model A Ford sight glass, but not as accurate. Sketch it out or play with an old sending unit. It becomes more obvious if you observe how it works. A fuel gauge is a bit of a dinosaur in this digital age, I'm afraid.

[eddieshep999]

A fuel gauge is a bit of a dinosaur in this digital age, I'm afraid.

Not unlike some of us

[Ga Blue Knight]

What really is needed is a Gas/temperature gauge!

[Jeriatric]

What really is needed is a Gas/temperature gauge!

Mine has one........it's called MY nose

Arrived in Idyllwild yesterday with a buddy of mine on his BMW. We had shut down, helmets removed and chit chatting. I said, hey Doug, come over here and smell this...he was ten or fifteen feet away and responded.........I don't need to. Enough said.

[cuznjohn]

mine was on 1/4 tank this morning when i went out so i filled it and it only took 3.4 gals of gas i need to do something about it

[rthomp32]

I feel your pain and agree that a $30000 machine should have better engineering. What is even more inexcusable is the BRP attitude. i spoke to a tech rep at BRP and he said that the gauge inaccuracy was normal and then just didn't answer any more emails on the subject. It sure feels like "we got your money so just deal with it." I think the outside air temp is more crucial for those of us that ride in the cold. nothing is more critical when traversing mountainous regions and not knowing if freezing conditions are occurring. I love my spyder but i hate BRP

[Mr. White]

M&M, I will solve your gas gauge problem. 1) Ignore your gauge, none are accurate. 2) Set your trip meter to zero after filling the tank. 3) Run 150 miles by your trip meter and GPS (to check accuracy of trip meter). 4) Fill tank...about 5 or 5.3 gallons as you will get around 30 mpg. 5) Ignore your gauge and go by trip meter....good luck. It works for me.

[Chupaca]

Get one of these Gas gauge.jpg when the rod drops down to the last notch your outta gas, if it fails drink a bottle of wine and jam the cork at the end of the rod and your good to go..!!

[NancysToy]

Roger, I have a question for you. You may have tried this, but I don't remember. I am curious as to whether if you tapped into the sender side of the wiring, before the cluster, and disconnected the guage side wiring, whether both the digital and analog gauges would work simultaneously? Have you ever tried?

[finless]

I have info for you.... I am uploading a test video now when I messed with these gages.
They maybe analog display but I think they are digital input not analog input! At least based on my testing of unplugging individual wires to the gages, etc.

Gas gage will work but temp gage will not if the digital display is on. stay tuned I will show my findings ina few minutes after it uploads to youtube.

Bob

[acinpcola]

Took the roadster (2011 RT S) over to GSPS this morning for a check on the fuel gauge for being way off. This was the replacement gauge for the bouncing one. Explained to them what was going on how I can fill the tank then at times it would not go to full, or after a stop in 20 or so miles I would fire it up and read 1/4 tank of gas. They hooked it up to their equipment and started looking to see if perhaps there was a problem. I had told them that no codes showed and all was well. After a while the service manager found me and took me back to the tech so we could talk. Seems that the cluster was the ill item, they explained to me that the cluster was not communicating with the the gauges correctly and was beginning to fail. So they ordered me a new cluster and now we just sit back and wait for the new one to get in so they can replace it. He did tell me that the roadster would still be driveable however I should memorize the start up sequence so I know when to push the buttons should the display fail before the new one arrives.

If you are ever in the Pensacola, FL area or Gulf Shores area of AL and your roadster needs some attention I highly recommend Gulf Shores Power Sports on Hwy. 59.

Will post a new thread when the replacement cluster is in.

Be Safe,

AC

[finless]

I played with this 3 days ago. I wanted to keep the temp gage but remove the fuel gage. Alas the signal to these gages is not analog! Well based on my testing anyway. The gage display is analog but the signal to them appears to be digital and on some kind of com buss (maybe the can-buss?).
FYI these gages also seem to be made custom for BRP based on labeling of them and no OEM info.

Here is a video I did showing testing results of messing with the gages.

I call this DIY fail because I was attempting to fool the system into thinking the analog gages were not there. I wanted to keep the analog temp gage and drop the gas gage. I figured this maybe was just some feedback loop to the digital display that could be bypassed or spoofed. Alas I believe it is not that simple!

Hey I could be all wet on this evaluation but based on the gas gage working but temp pegging, there is a signal control somewhere I am missing?





Bob

[acinpcola]

I played with this 3 days ago. I wanted to keep the temp gage but remove the fuel gage. Alas the signal to these gages is not analog! Well based on my testing anyway. The gage display is analog but the signal to them appears to be digital and on some kind of com buss (maybe the can-buss?).
FYI these gages also seem to be made custom for BRP based on labeling of them and no OEM info.

Here is a video I did showing testing results of messing with the gages.

I call this DIY fail because I was attempting to fool the system into thinking the analog gages were not there. I wanted to keep the analog temp gage and drop the gas gage. I figured this maybe was just some feedback loop to the digital display that could be bypassed or spoofed. Alas I believe it is not that simple!

Hey I could be all wet on this evaluation but based on the gas gage working but temp pegging, there is a signal control somewhere I am missing?





Bob

Your video and conclusion makes sense to me after my talk this morning with the tech and service supervisor about my fuel gauge.

AC

[finless]

If I truly understood what was going on I'd be able to supply a drawing and an explanation.

But I can't.
The gauges though, I don't think, are digital.
They are common analog gauges.
I think what you are seeing with the pegging of temp gauge is a loss of signal ground.
At bootup the cluster determines the gauges are not connected and cuts the analog signal path.

Good video.

At the end if you see I had a meter on the handlebars. I checked ground. It is not being interrupted.
Also the gas meter does not need +12V to work but I can tell you the temp does!

Now it has been a while since I messed with old school analog gages on my VW's. But back then you had +12, gnd, and a signal wire. True analog just like your drawing above shows. For temp it was just a thermistor. For gas or liquid, it was a signal like you drew up.

The S and I connections seems to be totally relevant though. I tried as I stated in the video unhooking them one at a time to see what they did. Also did it to each gage one at a time and then both! So there seems to be some kind of data loop here and not just a resistive or current sense loop back to the CPU telling it the gages are hooked up or not. So in my opinion the cluster (or CPU) is sending a signal or not to the temp gage (or possibly a different signal to digital vs analog gages). However the gas gage seems to work differently as you can see it works plugging in after boot up.

So, again in my opinion these are not simple analog signals. At least I do not think they are.

If I had my O-scope handy (it's on loan right now) I would find out for sure. Project for next week I think

Bob

[NancysToy]

Saying maybe I could help you hotshots where electronics is concerned is sure a stretch!

Your assessment of the cluster converting the digital signal and converting it to analog makes some sense, considering that is how they create the analog speedometer and tach outputs. Not so sure that the fuel circuit is purely digital, however, based on it working when hooked back up, and based on the fact that the fuel sender seems to be a resistance loop instead of a direct digital output. The wiring diagram does not show these gauges as being connected to the CANbus, so any digital conversion must be happening in the cluster. I am not surprised that Roger's testing yielded no results. A fuel gauge circuit needs power, or the resistance has no affect because there is nothing to resist. I guess we need to face it...the analog gauges are certainly not the extra cost enhancement they were intended to be.

[finless]

Interesting analysis!

I will use this and see if I can block the return with a diode so the digital system knows no better.

I want my analog temp gage! That's all I care about. The fuel gage can go bye bye for a volt/amp meter.

FYI I never tried feeding +12 to I connection. So that might be the key.

Bob

[finless]

But wait...... why if the temp gage is hooked up but NOT the fuel gage does the temp gage meter peg?

Something is still missing I think.

There is a orange/red wire that goes to both gages on the S (as I recall) line. This is a common wire to both when I metered it out... Maybe it was the I line supplying +12. Now your going to make me pull the dash apart again

Bob

[NancysToy]

The orange/red wire should be power for the light.

[finless]

Because the cluster disconnects BOTH signal wires if it finds an open circuit on either the temp or the fuel.
An open signal wire on the temp equates to a pegged meter as shown.

OK so no way then to spoof the cluster into thinking fuel gage is not there and thus digital display yet still having the signal go to the analog temp gage?
Unless we can figure out what input pin on the cluster connector that feeds temp sensor, and also route it to the analog temp gage?

Bob