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

[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]

Fuel Gauge check at Gulf Shores Power Sports, in AL.

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:spyder2:

 

[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]

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

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

 

[finless]

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

No not correct. There is another wire for the light. I forget it's color now and my video does not show it well.

Time to take it apart again and have another go.

Bob

 

[finless]

Well Scotty asked if I had ever connected the analog gauge to the sender prior to entering the cluster.

I now suspect you might be able to get both gauges that way.
What I don't know is how much that would
1)compromise the accuracy and
2) would you, by essentially trying to drive two loads instead of one, fry something the cluster.

What happens in the cluster, as they say, stays in the cluster.

For me, although quite adventuresome I wouldn't try it on mine.

I will try it myself. As for load causing inaccuracy, that can be adjusted by a pull up resistor or possibly a blocking diode.

When I return from my trip to Connecticut, I plan to dig into this again. Thanks for the info and findings!

Something that might help is reading the resistance between I, S, and ground on each gage.

Bob

 

[NancysToy]

No not correct. There is another wire for the light. I forget it's color now and my video does not show it well.

Time to take it apart again and have another go.

Bob

OK, I took a second look at the wiring diagram and it shows OR/RD for both the light and the gauge power. The light shows a 20 ga wire and the gauge power (I terminal on the gauge or P terminal on the diagram) shows an 18 ga wire...same color. They tie to a common junction ahead of the cluster.

The sticky part of making both the digital and analog gauges functional is that the fuel gauge is fed its signal from the sender, in parallel with the cluster, but the temperature gauge is fed its signal from the cluster, by way of the ECM. That explains why the temperature gauge acted differently in your tests. I don't think we could ever get both the digital and analog gauges functional and accurate at the same time, in any combination. It does appear that the gas gauge could be replaced with a different one, however. The trick would be to find a matching temperature gauge that worked. Roger found an interesting AutoMeter programmable fuel gauge.

 

[Ronbo]

Fuel Gauge

2013 RT LTD with 3000 miles. My fuel gauge does not show good correlation with the exact amount of gallons that the spyder will take. Yeah, it's not exact, but provides a good enough picture of the fuel situation to keep from running out. It really doesn't take away from the fun of riding. Good luck!

ronbo

 

[NancysToy]

The fuel gauge I found I'm afraid isn't the silver bullet I had hoped.
It is programmable but a look at the instructions indicates it can only be programmed for two set points EMPTY and FULL.
It appears it then just linearizes between those two points just like the stock gauge.


http://www.autometer.com/productPDF/0994A.pdf

The time is right for you to invent one that is fully progammable. Don't forget the value engineering so we can afford it, though. :roflblack:

 

[finless]

Scotty, can you look at the diagram and see where the temp sensor is mounted on the engine? Does it show what kind of sensor it is e.g. external like a thermistor, etc? Or maybe internal like it is reading oil temp?
Then does it show where this sensor comes into the cluster (what pin, wire color, etc)?
If we can pick that off before it goes into the cluster, we might be able to have both digital and analog temp gages.
This is what I want to keep is the analog temp gage. I am not casing the fuel gage myself as I want to replace that with volt/amp gage.

Thanks,
Bob

 

[NancysToy]

Scotty, can you look at the diagram and see where the temp sensor is mounted on the engine? Does it show what kind of sensor it is e.g. external like a thermistor, etc? Or maybe internal like it is reading oil temp?
Then does it show where this sensor comes into the cluster (what pin, wire color, etc)?
If we can pick that off before it goes into the cluster, we might be able to have both digital and analog temp gages.
This is what I want to keep is the analog temp gage. I am not casing the fuel gage myself as I want to replace that with volt/amp gage.

Thanks,
Bob

I believe you will find the coolant temperature sensor on the left side of the rear cylinder head. There is a connector near the sensor. The sensor is wired to the ECM at terminals ECMA-A1 and ECMA-J2. The sensing wire to the gauge is fed from the cluster at terminal CL-2. I would caution you against paralleling anything on the sensor side of the circuit. The coolant temperature enters is included in the EFI logic, and altering the resistance could adversely affect the engine operation. JMHO. I'd look for an unused port on the other cylinder head, install an addition sensor, and run that directly to the gauge or an aftermarket gauge).

 

[finless]

Thanks for the info!
I understand your caution but you should be able to tell if piggy backing off the signal effects the input. If so then the alternative is what I might do.
Do you suppose the sensor is "off the shelf" or proprietary to BRP?

Bob

 

[NancysToy]

Thanks for the info!
I understand your caution but you should be able to tell if piggy backing off the signal effects the input. If so then the alternative is what I might do.
Do you suppose the sensor is "off the shelf" or proprietary to BRP?

Bob

I am pretty sure it is made to their spec, but it may well be a suitable standard part. The resistance values are given in the shop manual.

 

[finless]

The resistance values are given in the shop manual.

This may help find a suitable off the shelf sender. Can you post the values?

Bob