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Bogus fuel mileage reporting. Grrrr.....


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15 hours ago, Grumpy Bear said:

1.) It takes two pieces of information to find the fuel efficiency. Distance traveled and the amount of fuel consumed over that distance. 

2.) Change tire height and it will change both speed and MPG data both directionally and in proportionality. Thus the distance needed from point one comes from the sensors that determine that distance and are used to calculate it. Easy-peasy. 

3.) Fuel used can either be calculated by measurement of injector pressure drop and look up tables OR by direct measurement as in the onboard fuel mass sensor which gives fuel used in pounds per hour. Second point from bullet number one.

4.) I own four GM's the oldest of which is a 2009 and the newest 2015. I track every drop of fuel and every mile logged and can tell you without exception that idle time is NOT a consideration. That is to say when the wife uses remote start twice to four times a day and tanks fuel economy to the low 20 mpg range it is off the same percent from the hand calculated values as the summer when I drive in on long trips logging 33+ mpg. 

5.) I can tell you that both the 2009 and one of the 2015's, both Buick cars are accurate to a tenth of an mpg no matter what an and the 2015's are 8.3% to 10% happy. Further the 2015 Verano and  2015 Terrain have the exact same power trains and fuel management systems. One is perfect the other...not even close.

6.) I can tell you that and you can tell me that I'm not seeing what I'm seeing and we just pee all over each others feet. 

to your point #3: Both of those electronically measured fuel numbers are instantaneous, right? If so, how can I find out the cumulative fuel usage for any length of time, such as my entire tank of gas? My truck tells me how many miles I've driven for a trip I set, but the only way I can currently gauge fuel is with the gas the pump. I can't see the programming inside the chip. I'm under the impression that the DIC error is introduced by taking the sum of 1000's of instantaneous readings, instead of taking the total miles/total gallons like I can do. Does anyone know how the DIC is programmed? Does it record the sum of fuel used?

 

I don't believe GM is intentionally misleading anyone, nor do they achieve some dark benefit by misleading.

The DIC is just doing its simple math and estimating a pretty close number. My readout is much closer than you report yours to be. There are so many variables that affect fuel economy, I'm sure there are just as many that affect how accurate the truck's calculation is compared to hand calculated totals.

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No they are going to be saying when's the next bus because they can't afford the $100,000 sub compact electric commuter car.  Sent from my Pixel 3 using Tapatalk      

Have any of you noticed that the reported fuel mileage is much higher than reality?  I track every drop of fuel my truck burns and my hand calculations are always a fraction of the fuel mileage that t

I have to admit, growing up watching my dad log every single thing in a note pad in the glove box on his vehicles, so I get where the mindset comes from.   Sadly though, in 20 years this pos

11 minutes ago, aseibel said:

to your point #3: Both of those electronically measured fuel numbers are instantaneous, right? If so, how can I find out the cumulative fuel usage for any length of time, such as my entire tank of gas? My truck tells me how many miles I've driven for a trip I set, but the only way I can currently gauge fuel is with the gas the pump. I can't see the programming inside the chip. I'm under the impression that the DIC error is introduced by taking the sum of 1000's of instantaneous readings, instead of taking the total miles/total gallons like I can do. Does anyone know how the DIC is programmed? Does it record the sum of fuel used?

 

I don't believe GM is intentionally misleading anyone, nor do they achieve some dark benefit by misleading.

The DIC is just doing its simple math and estimating a pretty close number. My readout is much closer than you report yours to be. There are so many variables that affect fuel economy, I'm sure there are just as many that affect how accurate the truck's calculation is compared to hand calculated totals.

The 'memory' serves that function. 

 

Are you saying that in your truck you don't have a resettable tank fuel economy number? Every one of mine do. In addition three of these have the last 'rolling' 25 mile, rolling 50 mile and rolling 450 mile displays that are also reset-able and do not display a value UNTIL the required distance has been completed while maintaining the last rolling average. Say for example I reset the 450 mile meter. The left side of the display will remain blank until it has covered 450 miles. The right side, that does not clear will continue the rolling average and at the 450 mile mark those two numbers will agree. It can and does walk and chew gum. It's a computer Andy and capable of any data manipulation required. I have an OBDII Scan Gauge II that cost me $125 that will display every data stream I have an address for and do the same calculations. Yes...it has a fuel "totalizer".

 

You EVER seen a GM fuel economy meter that gives a LOWER number that the hand calculated value? Me either! Thus, that error in not just intentional it is directional. When this happens repeatedly the same AND can be manipulated with gear or tire size in like and kind then that error, whatever it is, is the result of the programs manipulation of the basic math. If this were not so then there would be as many meters off UNDER as OVER. 

 

I can't do anything about what you choose to believe and honestly I don't want to. Again...I was asking for opinions as to the WHY of it, not the REALITY of it.   

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3 minutes ago, Grumpy Bear said:

Are you saying that in your truck you don't have a resettable tank fuel economy number?

 

I can't do anything about what you choose to believe and honestly I don't want to. Again...I was asking for opinions as to the WHY of it, not the REALITY of it.   

Yes, mine has the same fuel economy readout options as Pepper. I asked if it can tell me FUEL USED. That is not an option on my display that I'm aware of. Until I buy a fancier scan tool to verify, I won't know if the fuel usage the computer is estimating is the same as what the gas pump tells me.

 

I don't know WHY GM is lying, I guess I chose to believe there was no nefarious motivation. Why do you think they are lying when anyone can prove them wrong with some simple 4th grade long division?

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I just throw this out because I don’t know any better. How does tire air pressure affect the on board fuel calculation? Over inflation versus under inflation. A smaller rim with a taller sidewall tire. Can that effect on board fuel calculations enough to differ from hand calculations?


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I just throw this out because I don’t know any better. How does tire air pressure affect the on board fuel calculation? Over inflation versus under inflation. A smaller rim with a taller sidewall tire. Can that effect on board fuel calculations enough to differ from hand calculations?


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C'mon Man

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6 hours ago, aseibel said:

Yes, mine has the same fuel economy readout options as Pepper. I asked if it can tell me FUEL USED. That is not an option on my display that I'm aware of. Until I buy a fancier scan tool to verify, I won't know if the fuel usage the computer is estimating is the same as what the gas pump tells me.

 

I don't know WHY GM is lying, I guess I chose to believe there was no nefarious motivation. Why do you think they are lying when anyone can prove them wrong with some simple 4th grade long division?

Linear Logic Scan Gauge II will let your read those data streams ? Yes there are others. Point was that the data is there and being used even if you can't read it without a tool. Some are bluetooth from the OBDII to your phone if you like. Even OnStar reports back info from your on board systems you can't read from the DIC and so does GM. 

 

On the bold point. There is what some people can do and then what most people will do and frankly....most won't. Not anymore anyway. I guess it's an old guy thing. There is also this....ever force a younger person in retail to count back your change by handing them the odd change AFTER they hit the transaction button that automatically does that for them? I've had some breakdown and cry. I took $60 off the same teller in three $20 tries at the same transaction. I knew her boss and gave it back but lord if addition and subtraction is that hard then long division will give them a heart attack. In the marketing classes I took what....40 some years ago....taking advantage of what people 'most often do' regardless of what is possible... that stuff is gravy. 

 

Ever wonder why the milk is always in the cooler on the back wall of the convenience store AND sold at a loss? Ever wonder why the guy you're making the deal with on that new truck NEVER has the authority to actually CLOSE he deal? Why the smocks of guys used as doctors in advertising are white? Why cops pick on red vehicles? Why a ham steak never looks like it did at home as it did in the display case? Why gasoline is priced in 9/10's of a cent? Why hotdogs and buns are not packaged in the same count? Why antiwrinkle cream is modeled on 20 year old kids? ( that one slays me). There are firms, marketing firms that coach businesses on the music to play while you're on hold, the background color in a showroom. How much sugar to put in a product. Why do businesses do this when any old fart on the planet can see right through it? Because we still fall for it.

 

What marketing and media does today shapes your choices 20 years from now, not just right now. They play not just the short game but the long con as well. Fred and Wilma Flintstone were the first TV couple ever to be broadcast as a couple in bed during prime time hours. Set the table and see who shows up; then leverage that... How did that turn out? Wife says the next Poise commercials will show blood.....she may be right. Slim fit condoms during prime time. Hey kids...lookie see...

 

Electric cars are in that space right now. Creating the space in peoples minds for space in the market in 15 years. It's how they roll now. Tell them it is so...then leverage that into reality. 

 

 

Am I the only guy who ever took business or marketing classes or just the only guy that will talk about it? It's been a really REALLY long time since any car company made cars....they just make money now. There is a reason for EVERYTHING and usually, it isn't for the consumers good.

 

The only thing worse that being taken is finding out the one that sad story was about....was you.  

 

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9 hours ago, Grumpy Bear said:

Some are bluetooth from the OBDII to your phone if you like.

I have a bluetooth reader. I use the free Torque app. I found a live readout of MPG's but I haven't found a "fuel used" gauge yet. Plenty of time to play with it. I'm driving some 800 miles this weekend and I plan to monitor it.

 

I'm well aware of all the sales tactics designed to target impulse shoppers. You and I may fall for them less often than others, but it must work or every store wouldn't do the same thing.

 

You really have the GM marketing geniuses playing the long game. If they really are trying to hook you into your next purchase by making you think you're getting 1 mpg better than you really are.

 

For what its worth, my window sticker told me to expect 18 mpg combined, and by golly, that's about what I get.

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1 hour ago, aseibel said:

I have a bluetooth reader. I use the free Torque app. I found a live readout of MPG's but I haven't found a "fuel used" gauge yet.

 

 

 

You really have the GM marketing geniuses playing the long game. If they really are trying to hook you into your next purchase by making you think you're getting 1 mpg better than you really are.

 

 

I have fuel used, fuel remaining on the Scan Gauge II reader.  When I refuel there is a screen for that where you correct the offset. The scan gauge is really close but it does not correct the DIC. When I bought Pepper the sticker said 24 mpg highway. A year or two later the EPA 'corrected' value was lowered I think to 22 mpg. I have a 28 mpg lifetime average but....I'm far from average, right? :crackup: Peppers best tank was a bit over 33 mpg over a tank. The DIC said almost 36 mpg

 

 :rollin:

 

I know you've heard of the "Hundredth Monkey". You don't need to convince them all, just a population large enough to give credibility to the rest so they all fall in line... ? 

 

The all electric car universe and self driving are actually a bit bigger than GM. They are the show used to convince the monkeys. This has been done before. Are you ridding a horse? Is it even legal to keep a horse anywhere but the farm? How did we get from the horse to the car to making a horse kept in town for daily transportation against the law? Answer....One person at a time until there were enough people to make it reality. Who drove that buss? Auto makers? Big Oil? Same bus, just a new bus driver. 

 

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Two of the smartest auto makers have gotten rid of or reduced their sedan inventory. 4 dollar gas may be on the horizon. A couple tenths fudging on truck fuel mileage wouldn’t help them. Wonder if they thought of that backing a guy who hates the oil producers. Or at least domestic ones.


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8 hours ago, KARNUT said:

Two of the smartest auto makers have gotten rid of or reduced their sedan inventory. 4 dollar gas may be on the horizon. A couple tenths fudging on truck fuel mileage wouldn’t help them. Wonder if they thought of that backing a guy who hates the oil producers. Or at least domestic ones.


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here in LA we're already at $4/gal this week atleast.  meanwhile out in the port of LA they got petroleum ships lined out to sea by the dozen. i cant see why covid should cause such congestion to unload.

 

 

meanwhile the Chinese now have a nice 4 door EV sedan, they claim to they can produce  1 car every 60 seconds, so  they will flog us with the cheapo  ev's, for $20,000 usd and gets 450km/charge.. how much is power going to cost us when these POS's arrive and we start consuming  more energy in a different form,

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