Whacky Trip Meter

[ButterSmooth]

Trip A and B cleared within 5 miles of each other, one at home one at the gas station. Took the ride and each trip meter reported different mileage numbers. Pretty strange -- any explanations?

 

[Bfromla]

Had one accidentally paused :dontknow:

 

[EdMat]

Trip A and B cleared within 5 miles of each other, one at home one at the gas station. Took the ride and each trip meter reported different mileage numbers. Pretty strange -- any explanations?

Looks like they are reading exactly as they should if cleared approximately 5 miles apart. What am I missing here?

 

[Peter Aawen]

The mpg figures shown are AVERAGES, so there being a difference like that between Trip A showing 23.7 mpg & Trip B showing 39.0 mpg simply means the riding you did in the 5 odd miles that the Trip A meter recorded and the other didn't just wasn't particularly 'economical' riding.... maybe you spent more of that 5 miles at 'wide open throttle' or varying reasonably quickly between idle & a handful of throttle than you did for the whole of the other 130 miles; or if you prefer to look at it the other way, possibly the bulk of the 130 miles was done at a steady cruising speed/reasonably stable throttle setting while the other 5 miles was not... That sorta 'difference thing' is quite likely going to happen whenever you (or your vehicle's computer ) uses a measure of 'instantaneous fuel delivery' to calculate an 'average miles per gallon' figure, only in this instant you can see the significant change that can occur quite quickly due to the basic calc being derived from a different 'snapshot' of time/miles/fuel use - all it takes is a big enough variation in the period not recorded by one meter vs the other & the difference you'll see can be substantial!! :thumbup:

However, if you think about it a little & extrapolate further, by putting a little effort into planning your ride & throwing in some throttle control, you actually CHOOSE to make one of those mpg readings show something phenomenal (or awful) just by gently coasting to a stop over a reasonably long distance prior to stopping instead of riding up hard to your planned stop at full throttle and maybe even giving it a few WOT blips in the last couple of seconds immediately before stopping to check the reading!! :shocked:

Those 'instantaneous fuel use/avg mpg' displays are at best, simply an easy to read/easily varied indication of how you've been using fuel in the last recorded period (ie, since you reset that particular trip meter) - any bias towards one end of the 'riding economically/thrashing the guts outta it' scale will of necessity make a noticeable dfifference!! So, if you want a RELIABLE average mpg instead of the widely variable 'instantaneous reading', you'll need to look at the amount of fuel used over quite a number of tank refills and a much larger number of miles travelled - the more refills/miles travelled you use for your avg mpg calcs, the more reliable the average will be! The less refills/miles travelled the greater the impact your immediate past throttle control/fuel use will have on that average, skewing your mpg reading significantly in whatever direction you twisted the throttle most!! :lecturef_smilie:

So I wouldn't worry about that difference too much; instead, look at your 'average mpg over total time of ownership' and simply Ride More, Worry Less! hyea:

 

[ButterSmooth]

...snip...

So I wouldn't worry about that difference too much; instead, look at your 'average mpg over total time of ownership' and simply Ride More, Worry Less! hyea:

Nope. 96% of the miles recorded were the same miles. The 5 miles in question were downhill to the gas station, so if anything the extra miles should have improved the reading, not made it 34% worse. No throttle jockey stuff going on anywhere, either. These readings are just an amusement/oddity kind of thing, and don't concern me in the slightest. I just think Nanny must be nipping at the bottle and that makes her less believable. Now if I had checked the oil, there would be some explanation -- 10 minutes of idling can impact mileage significantly. Zeros are hard to deal with in any piece of software. The 39 mpg should indicate how I ride. Today's ride (175 miles, 2800' to 7000' elevations) produced 40.2 mpg.

 

[Peter Aawen]

Nope. 96% of the miles recorded were the same miles. The 5 miles in question were downhill to the gas station, so if anything the extra miles should have improved the reading, not made it 34% worse. No throttle jockey stuff going on anywhere, either. These readings are just an amusement/oddity kind of thing, and don't concern me in the slightest. I just think Nanny must be nipping at the bottle and that makes her less believable. Now if I had checked the oil, there would be some explanation -- 10 minutes of idling can impact mileage significantly. Zeros are hard to deal with in any piece of software. The 39 mpg should indicate how I ride. Today's ride (175 miles, 2800' to 7000' elevations) produced 40.2 mpg.

But the Nanny doesn't lie, and she doesn't drink either :shocked: And the computer that provides that readings on your dash is NOT going to be very likely to get the actual calcs that it does to arrive at said figures wrong; so the results of those calcs that you see on the dash are almost certainly CORRECT for the info from the various sensors; and that info came from the various sensors that measure instantaneous fuel delivery and the distance travelled & likely a bunch of other stuff besides.... so given that the maths itself is correct; and that the figures from the sensors are very likely reasonably consistent if not necessarily 'exactly' correct; then regardless of what you might say or think Butters, there WAS almost certainly some difference in that 5 miles that caused a variation in the instantaneous fuel use readings that went into calculating the average mpg readings shown. :lecturef_smilie:

You might not be aware of exactly what it was, or how much the tiniest variation might impact those readings; I'm certainly not in a position to say exactly what it was that did it either; it could be one or more of SOO MANY things!! Heck, it might've even been just the difference caused by the first start being a 'cold start' and so needing a heavier squirt of gas from each injector to get the engine going vs your second start being a 'warm start' and not needing that much gas - but you don't know & I really don't know that or exactlybwhat it was!! :dontknow: But I DO know that even the tiniest variation in distance &/or intantaneous fuel use readings can often have a markedly disproportionate impact on those 'short term/intantaneous mpg figures', and at best, those figures are really only useful as the amusement/oddity kind of thing you mentioned/I bolded & underlined above! :thumbup:

So like I wrote earlier, if you want a RELIABLE average mpg instead of the widely variable 'instantaneous reading' you are highlighting as showing a difference, you'll need to look at the amount of fuel used over quite a number of tank refills and a much larger number of miles travelled - the more refills/miles travelled you use for your avg mpg calcs, the more reliable the average will be! The less refills/miles travelled the greater the impact your immediate past throttle control/fuel use will have on that average, skewing your mpg reading significantly in whatever direction you twisted the throttle most!! :lecturef_smilie:

And THAT's why I say you shouldn't worry about that difference too much; instead, look at your 'average mpg over total time of ownership' and simply Ride More, Worry Less! hyea:

 

[ButterSmooth]

But the Nanny doesn't lie, and she doesn't drink either :shocked: And the computer that provides that readings on your dash is NOT going to be very likely to get the actual calcs that it does to arrive at said figures wrong;

I agree with that 100%, which is why I'm amused by the display. After an electrical engineering career, focused on embedded systems and software, I know that not all results are reasonable even in the best of systems. "NOT...very likely" is exactly correct -- humans design algorhythms and write code, so wiggle room is always needed.

Ride More, Worry Less! hyea:

Always the best advice. Disclaimer: I take no responsibility for your developing case of Carpal Tunnel Syndrome :shocked:...

 

[ARtraveler]

Recommend another test....set both A & B to zero at the same time. The readings should be exactly the same when you check them.

Can't explain the 5 mpg difference readings at this time.

 

[ButterSmooth]

Recommend another test....set both A & B to zero at the same time. The readings should be exactly the same when you check them.

Can't explain the 5 mpg difference readings at this time.

This whole thing was just an amusing observation; It's not worth any effort, although it's not the first time I've seen it. Those MPG readings have NO effect on riding. My background just makes me watch for unreasonable results, which usually point to some minor software flaw. IT'S INSIGNIFICANT and I don't need a reason or 'fix'. Remember Toyota's run-away throttle bug?? Now that's serious.

 

[EdMat]

What i noticed was the max speed was reached in the first 5 mile segment. I know at 76 I would be down in the 20's.

Mine also is off by about 3 MPG computer vs actual with actual being higher.

Sometimes it's fun to leave out with it showing 120 miles to empty and then do 40 miles of slower back country roads and come home it it shows 125 miles to empty.

 

[ButterSmooth]

What i noticed was the max speed was reached in the first 5 mile segment. I know at 76 I would be down in the 20's. ...

Ya, that's a bogus number too. I don't scream down residential roads 75+. And regardless of what Nanny says, this bike hasn't been to 80 mph yet. Fun to muse over though...

 

[Peter Aawen]

Ya, that's a bogus number too. I don't scream down residential roads 75+. And regardless of what Nanny says, this bike hasn't been to 80 mph yet. Fun to muse over though...

Yeah, that 'pre-delivery' installation of 80mph as Max Speed is just a little odd!! It seems as tho even some Spyders with just a couple of hundred yards on their odo show that?!? :shocked: I wonder if it's something that BRP's software mob have done deliberately, maybe to avoid one of those 'null state' display issues?? :dontknow: Or is there a crazy rider on the end of their production line that tries REEEAAAALLY HARD to make sure every Spyder hits 80mph in the 400 yards between the end of the production line & the 'crate packing/dis-assembly station'??

Oh, & you don't need any disclaimers, there's no Carpal Tunnel syndrome here - while I can/do touch type a lot & pretty fast, Talk to Text software is a wonderful thing that's very handy.... but I am intrigued with some of the letters it's taken to occasionally inserting when I ask for a 'space'.... sometimes it tosses in a 'v', or a 'c', but occasionally even a 'b'??? I can't be speaking as clearly as I once did?! :dontknow:

 

[ButterSmooth]

... Or is there a crazy rider on the end of their production line that tries REEEAAAALLY HARD to make sure every Spyder hits 80mph in the 400 yards between the end of the production line & the 'crate packing/dis-assembly station'??

My first inclination was to reply to this with a hardy HA!, but decades ago I worked for Peterbuilt and my experience there makes this explanation totally plausible... It would probably be higher if he had more than 400 yards!

 

[EdMat]

Ya, that's a bogus number too. I don't scream down residential roads 75+. And regardless of what Nanny says, this bike hasn't been to 80 mph yet. Fun to muse over though...

My max speed numbers have always been pretty accurate on mine.They are hardly ever the same between the 3 tho. I uses A for service interval so its only getting reset about every 9,000 mies. B is used between fuel stops so it makes the biggest swings. C only the averages and max can be reset, not the total mileage or hours. Don't remember what it was at from new but I have reset it a time or three so it does not show anything over the century mark.