Taking to shop for MPG issues; what to check?

[jblc]

short of a thermal camera to see rotor temperature this is the next best

Yeah, actually in the meantime I thought of using my thermal camera as well, so that seems best

Just don’t mire yourself into speculation and rhetoric… do something and test it out. Sometimes small changes will result in great results.

Yep, agreed, and thanks for the reminder/encouragement! I'm working my way through a list of things to check from this thread, eg checking plugs, so it'll take some time but there are actionable tests

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[pbethel]

As documented in various threads on the matter, dealers are plenty willing to brush off Blackstone reports.

Yeah, your right.
Just wait until dealer blows him off then he can fire the parts cannon at it.

 

[Gizmokid2005]

Hand calculating is useless...needs to be done properly via an app, the dash, a Scan Gauge.
Auto start/stop is not really saving much, and is offset by the lots of extra that's put on the starter.

I cannot state just *how* incorrect this is. I don't know what you understand "hand calculating" as, but it will always be the most accurate calculation you can do assuming you have accurate gas pumps (fill to roughly the same level) and accurate mileage readings (your speedo/odo are correct).

The dash is historically *incredibly* generous, and for most people 1-2mpg off, if not more, from what actually is being achieved. Apps and scan gauges can be afflicted by similar, and different, problems as the dash. Unless they're actually reading fuel pumped into the engine (using fuel flow/etc) and combine it with distance traveled, they're going to be off as well. Even using things like Torque, I've never managed to get any closer to actual mileage than the dash is.

They key to proper mileage is proper measurements (if you change your tire size you need to calibrate your speedo so distance is correct, and make sure you're filling to as close to the same point every time as you can - trying to use the same station/pump if you can, filling to the same point (first click, wait 30s, fill until it clicks again), you'll be less affected by variances here if you usually put in 1/2 tank or more, especially given how little volume actually varies there), and using those, a hand calculation is as accurate as you get (whether it's legit doing the math with a calculator or plugging the values into Fuelly or something, which is the same thing).

Also Auto start/stop isn't offset by starter wear, starters these days are designed for the duty and load cycles of an auto start/stop system, and that wear has no impact on your fuel mileage. They could offset fuel savings if they wear out faster, but that's not historically the case and still isn't a direct impact to MPG.

 

[Grumpaw]

I cannot state just *how* incorrect this is. I don't know what you understand "hand calculating" as, but it will always be the most accurate calculation you can do assuming you have accurate gas pumps (fill to roughly the same level) and accurate mileage readings (your speedo/odo are correct).

The dash is historically *incredibly* generous, and for most people 1-2mpg off, if not more, from what actually is being achieved. Apps and scan gauges can be afflicted by similar, and different, problems as the dash. Unless they're actually reading fuel pumped into the engine (using fuel flow/etc) and combine it with distance traveled, they're going to be off as well. Even using things like Torque, I've never managed to get any closer to actual mileage than the dash is.

They key to proper mileage is proper measurements (if you change your tire size you need to calibrate your speedo so distance is correct, and make sure you're filling to as close to the same point every time as you can - trying to use the same station/pump if you can, filling to the same point (first click, wait 30s, fill until it clicks again), you'll be less affected by variances here if you usually put in 1/2 tank or more, especially given how little volume actually varies there), and using those, a hand calculation is as accurate as you get (whether it's legit doing the math with a calculator or plugging the values into Fuelly or something, which is the same thing).

Also Auto start/stop isn't offset by starter wear, starters these days are designed for the duty and load cycles of an auto start/stop system, and that wear has no impact on your fuel mileage. They could offset fuel savings if they wear out faster, but that's not historically the case and still isn't a direct impact to MPG.

Yoda say's....
Hard to "hand calculate" when it is only 3 fingers you have.....

 

[Grandaccess]

city/highway or even towing mine seems to hang right around 22mpg
I try and fill up with 92 oct/non-Eth

 

[Trigganometry]

I cannot state just *how* incorrect this is. I don't know what you understand "hand calculating" as, but it will always be the most accurate calculation you can do assuming you have accurate gas pumps (fill to roughly the same level) and accurate mileage readings (your speedo/odo are correct).

The dash is historically *incredibly* generous, and for most people 1-2mpg off, if not more, from what actually is being achieved. Apps and scan gauges can be afflicted by similar, and different, problems as the dash. Unless they're actually reading fuel pumped into the engine (using fuel flow/etc) and combine it with distance traveled, they're going to be off as well. Even using things like Torque, I've never managed to get any closer to actual mileage than the dash is.

They key to proper mileage is proper measurements (if you change your tire size you need to calibrate your speedo so distance is correct, and make sure you're filling to as close to the same point every time as you can - trying to use the same station/pump if you can, filling to the same point (first click, wait 30s, fill until it clicks again), you'll be less affected by variances here if you usually put in 1/2 tank or more, especially given how little volume actually varies there), and using those, a hand calculation is as accurate as you get (whether it's legit doing the math with a calculator or plugging the values into Fuelly or something, which is the same thing).

Also Auto start/stop isn't offset by starter wear, starters these days are designed for the duty and load cycles of an auto start/stop system, and that wear has no impact on your fuel mileage. They could offset fuel savings if they wear out faster, but that's not historically the case and still isn't a direct impact to MPG.

I use Fuelly app and plug in data from a printed receipt. I go all the way to 3 place decimals. It’s just as accurate as your hand calculator and I verify input by dollar amounts being exact to each other. Now I also have a stored record now of that fillup.

 

[Gizmokid2005]

I use Fuelly app and plug in data from a printed receipt. I go all the way to 3 place decimals. It’s just as accurate as your hand calculator and I verify input by dollar amounts being exact to each other. Now I also have a stored record now of that fillup.

Yup. Fuelly is just fine. I started an excel doc back in like 2006 that I've just used ever since for all my vehicles, since before Fuelly was a thing, but it just does the same math for you without you needing to do any manual stuff. Just give it values and it spits out your result. It's a tool that's perfect for what it needs to be.

 

[Grumpaw]

I use Fuelly app and plug in data from a printed receipt. I go all the way to 3 place decimals. It’s just as accurate as your hand calculator and I verify input by dollar amounts being exact to each other. Now I also have a stored record now of that fillup.

I use the FUDFUA method.....
FillUpDriveFillUpAgain
Fool proof and always accurate !!!

 

[Joeiconic]

Yup. Fuelly is just fine. I started an excel doc back in like 2006 that I've just used ever since for all my vehicles, since before Fuelly was a thing, but it just does the same math for you without you needing to do any manual stuff. Just give it values and it spits out your result. It's a tool that's perfect for what it needs to be.

You‘ve kept a gas tracking spreadsheet for 17 years? Is that for business expense reasons?

 

[Dextrose]

I use Fuelly app and plug in data from a printed receipt. I go all the way to 3 place decimals. It’s just as accurate as your hand calculator and I verify input by dollar amounts being exact to each other. Now I also have a stored record now of that fillup.

WOW, that's a great price for fuel! I'm over $5 for premium in Comifornia.

 

[Gizmokid2005]

You‘ve kept a gas tracking spreadsheet for 17 years? Is that for business expense reasons?

Nope! I use MPG tracking as a way to help budgeting for vehicle upgrades/replacements, as a very basic indicator of potential "non broken" issues with a vehicle as mileage is usually the first hit when something goes awry. It also helped me figure out brands with the "best" mileage potential (usually places like BP, Shell, Costco, and QuikTrip).

 

[Joeiconic]

Nope! I use MPG tracking as a way to help budgeting for vehicle upgrades/replacements, as a very basic indicator of potential "non broken" issues with a vehicle as mileage is usually the first hit when something goes awry. It also helped me figure out brands with the "best" mileage potential (usually places like BP, Shell, Costco, and QuikTrip).

Wow, I don’t even balance my checkbook.

 

[Gizmokid2005]

Wow, I don’t even balance my checkbook.

I do that too, not as often as I used to now with transaction syncing with my local software, but...

 

[KJRR]

Wow, I don’t even balance my checkbook.

As long as you have checks you are good.

 

[Msfitoy]

Nope! I use MPG tracking as a way to help budgeting for vehicle upgrades/replacements, as a very basic indicator of potential "non broken" issues with a vehicle as mileage is usually the first hit when something goes awry. It also helped me figure out brands with the "best" mileage potential (usually places like BP, Shell, Costco, and QuikTrip).

Thanks for sharing the amount of gas used in 93K miles...I think I'll just park my truck now...

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