Trip computer doesn't reset all?

[JF1444]

I've only had my GT-AWD for a couple of weeks now and still < 500 kms on it. Finally got it out for a ride on the highway this afternoon 100kms each way. Before heading out I reset the trip A readings. I kept an eye on the 'current' litres/100 as I drove and never saw it go over 9. Stayed at about 6-7s for most of the trip. My speed was 100-110kms/hr for 90% of the trip.
Once I got back I scrolled through trip info settings and the trip computer gave me an average consumption of 10.1! Odd...
The average kms/hr was 42!! That is impossible! The trip was 1 hr each way and the only time I slowed down was once I got off the highway. And that for at most 5 minutes with no stoplights.
Scrolling through the B settings (lifetime since I never reset it) also displayed the same 42kms/hr average speed and the 10.1 consumption!

This all leads me to believe that the reset doesn't actually reset anything. What I read in the A trip is simply what is stored in the B. Anyone else notice this behavior with theirs?

 

[Buger]

The A and B trip counters only count miles driven since last reset and have nothing to do with the average fuel economy or average speed. I have the sport 6MT and you have to press the center of the info button in and hold for a couple of seconds while on the average fuel economy or average speed to reset them.

 

[JF1444]

The A and B trip counters only count miles driven since last reset and have nothing to do with the average fuel economy or average speed. I have the sport 6MT and you have to press the center of the info button in and hold for a couple of seconds while on the average fuel economy or average speed to reset them.

Thanks for the info. Should have first read the manual...

In my old car (VW Passat), a reset, reset all for that 'trip counter'. No need to go thru each one in the set.

 

[paris1]

OK, here's what I've noticed about average fuel economy reset: I currently have about 1500 miles total on my car. I purchased it in SoCal and drove it 565 miles home (all freeway) to NorCal. On that trip, with a fresh engine, I got better than 34 mpg (verified by at the pump hand calculation). After refilling at home, I hit the reset thinking I would then check to see what my in-town mileage would be with my now broken-in engine. Burned off 3/4 of that tankful with strictly city driving and noted that the avg. mileage reading was right around 32 mpg. However, as I suspected, actual calcuation showed 28 mpg, so it appeared to me that the trip computer reading had not reset after all, but was still averaging the first reading with my current driving. Since then, I've observed that the avg. mileage figure is slowly coming down towards the 28 or so actual mpg I am getting in-town (where most of my driving occurs), so I've pretty much concluded that resetting the trip computer is simply a placebo and that the average mileage reading remains a lifetime average no matter how many time you push the reset. Anyone have experience that would disprove this theory?

 

[Buger]

I reset my average fuel economy (hold down info while on average fuel economy) and average speed (hold down info while on average speed)every time I fill up the gas tank as I like my wife to be conscious of it as she usually drives the CX-5. Our average speed per tank has varied from 19mph to 58mph (different each tank). Our average fuel economy readout has varied from about 28-38mpg (different each tank). Our actual fuel economy (miles between fillups / gallons filled) tracked by fuelly was about 26.x to 36.x mpg.

So I can say that for our CX-5 there all works as intended. Are you sure you reset both the average fuel economy and average speed? I'll let others chip in with their experiences alsot though. You probably aren't doing it right if you are only seeing a running average. Maybe only the 6MTs are good.

 

[paris1]

I reset my average fuel economy (hold down info while on average fuel economy) and average speed (hold down info while on average speed)every time I fill up the gas tank as I like my wife to be conscious of it as she usually drives the CX-5. Our average speed per tank has varied from 19mph to 58mph (different each tank). Our average fuel economy readout has varied from about 28-38mpg (different each tank). Our actual fuel economy (miles between fillups / gallons filled) tracked by fuelly was about 26.x to 36.x mpg.

So I can say that for our CX-5 there all works as intended. Are you sure you reset both the average fuel economy and average speed? I'll let others chip in with their experiences alsot though. You probably aren't doing it right if you are only seeing a running average. Maybe only the 6MTs are good.

I only reset the average MPG; why would average MPH have anything to do with it? I have never understood why the included that calculation on the display anyway!

 

[Buger]

I only reset the average MPG; why would average MPH have anything to do with it? I have never understood why the included that calculation on the display anyway!

You don't need to reset both but you may have reset the wrong one or you didn't hold it down long enough if you don't see any change in your average fuel economy.

The avg speed can be interesting as it has a big correlation with your fuel economy. Personally, I keep note it on my fuelly updates for each fillup. If my wife almost exclusively drives a tank and I see it is averaging 19 mph, it isn't a surprise when I see the avg fuel economy is down at 26 mpg also.

Try resetting it again and paying close attention to it.

 

[paris1]

You don't need to reset both but you may have reset the wrong one or you didn't hold it down long enough if you don't see any change in your average fuel economy.

The avg speed can be interesting as it has a big correlation with your fuel economy. Personally, I keep note it on my fuelly updates for each fillup. If my wife almost exclusively drives a tank and I see it is averaging 19 mph, it isn't a surprise when I see the avg fuel economy is down at 26 mpg also.

Try resetting it again and paying close attention to it.

Thanks for the response, but I have done exactly as you have suggested and have stated the result. That won't change by doing it again. I happened to check the avg. mpg again today and it is still slowly drifting down (currently 29.1) towards the actual 28 mpg or so I am getting around town.

 

[Buger]

One last question: When you reset the average speed, do you see it go to 0.0 after holding the info down? You keep mentioning it slowly drifting down from 32 as if it never gets reset and never goes to 0.

 

[paris1]

One last question: When you reset the average speed, do you see it go to 0.0 after holding the info down? You keep mentioning it slowly drifting down from 32 as if it never gets reset and never goes to 0.

I never reset the average speed. Why would I? I reset the average MPG @565 miles and it went to zero. Next reading was about 32 MPG @ about the 900 mile mark when it should have read 28 by my calculation. It's been slowly drifting downward since which is consistent with the type of driving I mostly do.

 

[Buger]

Ok, i meant average fuel economy. I just wanted to know if you saw it go down to 0. Whenever I first reset mine it starts at 0 then I can see the avg mpg changes very quickly at first. For example if you take a short 1 mile drive, you'll see it can be very low like 20mpg or something. Then if you take a highway trip for 10 miles, you may see it jump to 30 relatively quickly. Once you get a couple of hundred miles in, it takes a bit more driving to change it much.

As I mentioned earlier, I reset it at each fillup so I'm very familiar with it and I just can't understand how anyone would could even think the reading is a "placebo" as it is very predictable and consistent for me. Understand that the fuel economy reading isn't 100% accurate. On a recent road trip, mine read 38.x mpg while I found I "only" got 36.5 when I filled up. Perhaps there is some built in inaccuracy or the TPMS was set when the tires were a different PSI than it currently is or whatever but it is definitely no placebo on my car.

If you already believe it is a bogus reading and don't want to try it again as you think it will be the same then there is nothing else for me to discuss on it.

 

[paris1]

Ok, i meant average fuel economy. I just wanted to know if you saw it go down to 0. Whenever I first reset mine it starts at 0 then I can see the avg mpg changes very quickly at first. For example if you take a short 1 mile drive, you'll see it can be very low like 20mpg or something. Then if you take a highway trip for 10 miles, you may see it jump to 30 relatively quickly. Once you get a couple of hundred miles in, it takes a bit more driving to change it much.

As I mentioned earlier, I reset it at each fillup so I'm very familiar with it and I just can't understand how anyone would could even think the reading is a "placebo" as it is very predictable and consistent for me. Understand that the fuel economy reading isn't 100% accurate. On a recent road trip, mine read 38.x mpg while I found I "only" got 36.5 when I filled up. Perhaps there is some built in inaccuracy or the TPMS was set when the tires were a different PSI than it currently is or whatever but it is definitely no placebo on my car.

If you already believe it is a bogus reading and don't want to try it again as you think it will be the same then there is nothing else for me to discuss on it.

Tell you what; just for laughs, I'll try it again next fillup. I agree it doesn't make sense that Mazda would include such a basic feature that doesn't work as advertised. Will report back here when I get a definitive result.

 

[Bcdad182]

I usually reset mine at each fill up. I know its working as it shows zero and then depending on how aggressively I drive or how many hills there are out of the gas station is really swings widely for the next day or so, and then it settles down once there is some distance on it. I sometimes will change the average speed, but not often, it's a useless number quite frankly. The longer you go without resetting it the average fuel reading, the harder it will be to move it away from an average number. I, like many here, use Fuelly and I notice that the Mazda tends to report significantly lower than Fuelly (about 3-4%) Both methods have their pros/cons, but I don't think it's enough to worry about.

I too have noticed that it doesn't have any connection to the A/B trip settings, which is unfortunate. My last Honda was tied to it and it was great as I could get immediate tank (on trip A) and a longer-term on trip B. With that vehicle, it was the same thing Fuelly was consistently higher than the vehicle computer, but again, by a very small percentage. Inherent issues with both methods means you'll rarely see them agree completely.

 

[Buger]

I hope you get a good result Paris1.

I know the avg speed is mostly useless and I was wondering why it was there too when i first found it. But I started resetting the average speed for each tank and found that it makes a really good predictor of the fuel economy. Below is the data for the few months that I've been keeping track of the speed and it seems the only data point which is outside the expected curve is the one where we were coming back on a road trip and got stuck in stop/go traffic on the freeway due to a couple of accidents then took a detour through some smaller cities to get back to Atlanta.

avg 19 mph avg 26.9 mpg {27.1, 26.7}
avg 20 mph avg 28.6 mpg {28.6}
avg 21 mph avg 28.8 mpg {28.8}
avg 24 mph avg 29.2 mpg {30.0, 29.3, 28.4}
avg 26 mph avg 32.5 mpg {32.5}
avg 47 mph avg 31.5 mpg {31.5}
avg 58 mph avg 36.5 mpg {36.5}

I kind of like digging into numbers though so I'm probably weird.

 

[paris1]

I hope you get a good result Paris1.

I know the avg speed is mostly useless and I was wondering why it was there too when i first found it. But I started resetting the average speed for each tank and found that it makes a really good predictor of the fuel economy. Below is the data for the few months that I've been keeping track of the speed and it seems the only data point which is outside the expected curve is the one where we were coming back on a road trip and got stuck in stop/go traffic on the freeway due to a couple of accidents then took a detour through some smaller cities to get back to Atlanta.

avg 19 mph avg 26.9 mpg {27.1, 26.7}
avg 20 mph avg 28.6 mpg {28.6}
avg 21 mph avg 28.8 mpg {28.8}
avg 24 mph avg 29.2 mpg {30.0, 29.3, 28.4}
avg 26 mph avg 32.5 mpg {32.5}
avg 47 mph avg 31.5 mpg {31.5}
avg 58 mph avg 36.5 mpg {36.5}

I kind of like digging into numbers though so I'm probably weird.

Interesting correlation and bit of CX-5 trivia, though I'm still clueless as to why Mazda included this feature on the trip computer readout. I've seen other cars over the years with much more useful/entertaining info.