what's up with my gas mileage?

[4Runner93]

I have 130 miles on my tank of gas right now. And I just hit the 1/4th line. :wtf:It has never been this bad, and it's completely stock. No lift or larger tires

I haven't driven any different than I normally do, and i could usually squeeze 200 out out after the light was on. Now that it's cold, I almost always let my truck warm up before I leave for school or on any errands.

 

[Opi]

winter gas is generally crappier and will give you worse mileage. i get around 200 and my gas light is on. 150 miles im below 1/4 tank. i get 15mpg mostly highway, ive determined anyone on here who says they get 20mpg is lying. sounds about right, when was the last time you did a general tune up?

 

[arracado]

I've seen a definite decrease since the winter months set in. I'm down to about 13.5 in-town. Thankfully my girlfriend has a Pontiac Vibe that we use for daily driving.

 

[arracado]

I also found this helpful regarding warm-ups:

Eight facts about warming up your car in winter - Yahoo! News

 

[98_4runnerSR5]

I have 130 miles on my tank of gas right now. And I just hit the 1/4th line. :wtf:It has never been this bad, and it's completely stock. No lift or larger tires

I haven't driven any different than I normally do, and i could usually squeeze 200 out out after the light was on. Now that it's cold, I almost always let my truck warm up before I leave for school or on any errands.

Winter has definitely brought much worse gas mileage for myself. I was getting 300ish to the tank and now I'm getting 230ish. I also recently did a tune up with spark plugs, fuel filter, etc before winter so I know that's not it. Winter's a killer!

I also found this helpful regarding warm-ups:

Eight facts about warming up your car in winter - Yahoo! News

Funny you mention this article. I read this the other day and thought about posting it somewhere on here. Good article... Found out a lot of myths that I didn't know before.

 

[durrell]

I'm averaging 275 miles on about 16 gallons. So that's roughly 17 MPG. Not sure why you guys are seeing such bad mileage. Of course, it could be the mild climate in NC but this has been a harsh winter with not many days above 40 degrees, so that doesn't make much sense.

 

[Headly]

is gasoline a standard commodity or is there a winter blend?

I saw talk of ethanol 15 but the pumps still have the up to 10% labels.

found this,says winter blend has 1.7 % less energy than summer blend

http://ask.cars.com/2009/02/whats-t...blend-gasoline-does-it-affect-my-cars-pe.html

I also saw on the Prius board people are complaining about 10% reduced mpg for winter gas. 17 - 3.4 = 13.6 if prius are an indicator

my gas mileage has been down a bit-~15-16 , fairly recent tune up and recent a/f sensor- I had a 0420 code and it went away with a repaired exhaust leak at the gasket of the rear end of the front cat to the straight pipe- I was hoping it was exhaust leak bad gas mpg and not winter gas,we'll see

 

[02SE]

Now that it's cold, I almost always let my truck warm up before I leave for school or on any errands.

While it's sitting there warming up, it's getting zero mpg. That will definitely bring your average mpg down.

 

[theizzardking]

While it's sitting there warming up, it's getting zero mpg. That will definitely bring your average mpg down.

meh, i can waste 1/2 a gallon or less on heating up the truck so i'm nice and toasty on my drive in.

you use about .64 gallons of gas for an hour of idle at 800 RPM, meaning it costs you about $1.50 or so to idle for an whole hour, that's 10 minutes every morning for almost a week, worth it imo to be warm and happy on the cold lame mornings drive into work.


if you want to see what sort of money and fuel your wasting on idling i found this cool little print out for you to fill out and see whats going on.
http://www.transportation.anl.gov/pdfs/TA/361.pdf

 

[PhdNPrerunners]

winter gas is generally crappier and will give you worse mileage. i get around 200 and my gas light is on. 150 miles im below 1/4 tank. i get 15mpg mostly highway, ive determined anyone on here who says they get 20mpg is lying. sounds about right, when was the last time you did a general tune up?

I have seen over 20 MPG a couple of times. On highway trips I can easily see 275 before the light comes on and mine comes on at about 13 gallons used. My last tank even with my new muds I saw over 18 MPG. Maybe we just have good gas here

 

[02SE]

meh, i can waste 1/2 a gallon or less on heating up the truck so i'm nice and toasty on my drive in.

you use about .64 gallons of gas for an hour of idle at 800 RPM, meaning it costs you about $1.50 or so to idle for an whole hour, that's 10 minutes every morning for almost a week, worth it imo to be warm and happy on the cold lame mornings drive into work.


if you want to see what sort of money and fuel your wasting on idling i found this cool little print out for you to fill out and see whats going on.
http://www.transportation.anl.gov/pdfs/TA/361.pdf

I don't care if he or you uses up the entire tank letting it idle to warm the 'Runner. It's your car, and you can do as you wish as far as I'm concerned. The only point I'm making is that it uses gas, and will negatively affect the average mpg.

When the engine is cold, it will also use more gas while idling, then it does when idling after the engine is already up to operating temperature. In cold temps the rest of the driveline is cold too, so there will be more drag from cold gear oil in the axle(s), transfer case if 4wd, cold oil in the transmission, grease in the u-joints and double-cardon joints, until they all reach normal operating temp.

Anyway, it all adds up to poorer mpg in Winter vs Summer conditions.

 

[theizzardking]

I don't care if he or you uses up the entire tank letting it idle to warm the 'Runner. It's your car, and you can do as you wish as far as I'm concerned. The only point I'm making is that it uses gas, and will negatively affect the average mpg.

When the engine is cold, it will also use more gas while idling, then it does when idling after the engine is already up to operating temperature. In cold temps the rest of the driveline is cold too, so there will be more drag from cold gear oil in the axle(s), transfer case if 4wd, cold oil in the transmission, grease in the u-joints and double-cardon joints, until they all reach normal operating temp.

Anyway, it all adds up to poorer mpg in Winter vs Summer conditions.

yeah but engine takes all of 30 seconds to 1 minute to reach operating temp and the extra drag your speaking of while in engineering terms is correct is negligible in real world applications, meaning that the extra amount of drag created by cold components in the drive train and the extra amount of gas used to reach operating temps is so small i doubt it would measurable by any means available to the average consumer.

there are 2,650 grams of gas in a single gallon.
your talking about 6-12 grams worth of fuel to idle for 30sec-1 minute to reach operating temps in the engine, and about 6-7 miles for drive train components to be at operating temp while moving,

i guess my point is, of course the engine uses gas while idling and of course if your not moving your mpg's will suck, you idle a whole tank of gas and then complain about getting 0mi/18.5 gallons i won't feel sorry for you......

seems like common sense to me, and like i said, even idling for 10 minutes a day isn't so expensive or very draining, if he's getting crappy fuel mileage he should run through all of the regular tune up routines so on and so forth.
and like you guys mentioned earlier you will get a mpg or 2 less this time of year due to the blend,i just don't see how idling is being pinned as the culprit for this guys bad mpg's, if he's noticing drastic changes something else is going on, i mean has this guy even actually tracked it?

don't get me wrong 02se your right, i'm just splitting hairs over here.

 

[02SE]

It can get far more complicated than that. But I don't want to spend the time typing out some long-winded dissertation on engine thermodynamics, and I doubt anyone would be interested anyway.

I was just pointing out that idling the engine is just one of many factors in poor winter time mpg's.

How long it takes for an engine to reach it's normal operating temperature range, is dependent on several factors. Just a couple of which are the temperature before the engine is started, and the load placed on the engine while it warms up. It will take significantly longer to reach operating temperature if the engine is at -30° F to begin with, then it will if the cold engine temp is a hot summer day of 95° F.

The in-dash temperature gauge really only shows broad ranges of temperature. It will show the same 'Normal' temp of just below halfway on the gauge, from about 150° F to over 200° F. If you have an actual coolant temperature gauge such as an Autometer temperature gauge, or a tool that can read the data via the OBDII port such as a Scangauge, Ultragauge, etc. you can watch just how much the actual temperature varies, all the while the in-dash gauge doesn't move from it's 'Normal' position.

Then we could talk about the kinematic viscosity in centistokes of the various oils at varying temps, and the effect that has on their flow characteristics. It takes much longer for the oils to reach operating temp, and their most fluid state, then it does the coolant. Then there's the question of whether there's any ethanol in the gasoline formulation being used, etc.

Ahh, It's all too involved for a simple question about winter time gas mileage. It's just cabin fever from sitting home during the racing off-season. :moping:

Bottom line is that all else being equal, colder temperatures generally have a negative impact on fuel economy.

 

[theizzardking]

It can get far more complicated than that.

it doesn't need to though does it? what i'm saying is forget the thermodynamics
(the laws and principles of energy exchange) and think about real world and measurable scenarios, the extra 2 minutes it takes for your motor to warm up @ 30 degrees as opposed to 50 degrees translates in to about 24 grams of gas, only being used at start up, same goes for all of this only used at start up.....

the time differences between warm up end up being pretty negligible imo,
they say you lose 5-15% of mpg's due to the winter blend of gas over 3 tanks alone,

i would say that right there is the only "real" reason, the other stuff is so minute imo, it's barley worth mentioning, maybe costs you .25 gallon over a tank, if your a normal person, more so if your me and don't care....

lol, like i said your right but it's really the gas and the gas alone man, i fully understand what your talking about, like i said your right but i think only when your talking around -10,-20 and -30 degrees , when the pour point depressant additives in the oil essentially stop working or are on the colder end of the spectrum is when you'd start seeing a larger more measurable quantity of gas being used to get that kinetic energy turned into work/heat and up to operating temps, i think most places in the lower 48 are pretty safe from that sort of entropy for the most part.



.....i'm bored too....lol

 

[theizzardking]

lol, i guess we could get crazy with and start assigning values to our variables and see at what temps it really does matter, lol
heck even create an ansys model of it and see what happens.......wait..i'm not that bored, lol

 

[Qyota]

I like the scientific banter here - it's good stuff.

One important note about long idle times is the collection of hydrocarbons in the catalytic convertor. Not good. During this time, the cat isn't doing it's job (because it isn't hot enough for the catalyst to work), and you are putting some pretty nasty stuff into the air, unnecessarily.

What really gets me is folks who idle their cars/trucks IN their garage. Even with the big door open, air will infiltrate the house, and you'll be inhaling plenty of CO and other noxious gases. That stuff builds up in your blood and can make life ****ty for you and your kids, without you even realizing the source.

Don't be a baby. You'll only be cold for a minute or two. If everyone did their part to not waste fuel by idling, we could make a difference in air quality and consumption of fossil fuels.

 

[Nelsonmd]

The in-dash temperature gauge really only shows broad ranges of temperature. It will show the same 'Normal' temp of just below halfway on the gauge, from about 150° F to over 200° F. If you have an actual coolant temperature gauge such as an Autometer temperature gauge, or a tool that can read the data via the OBDII port such as a Scangauge, Ultragauge, etc. you can watch just how much the actual temperature varies, all the while the in-dash gauge doesn't move from it's 'Normal' position.

I disagree with this. I have a SGII and often watch the engine temp rise in the morning and how that compares to the in-dash gauge. The dash gauge consistently passes the lowest mark on the gauge at 150° and rests at the middle at 190°. Every time. I was pretty surprised how consistent it was. I have noticed it rise just above center when it went up to 210°.

Frankly, the biggest contributors to fuel economy are driving speed, aggressiveness, tire pressure (which drops when it gets cold, so check your tires), driving in 4WD, etc. Yeah the engine temps takes longer when it's cold (duh) but it is not much longer on the scale of how long you are driving it, so unless you are leaving it for 15 minutes or more, or just driving a short distance every time you let it warm up, you aren't going to notice that much in your overall mpg's. And referring to "centistokes" is just scientific name-dropping.

I have noticed that my driving style has changed a little bit with bad weather, and traffic patterns cause me to lose some mpg's because traffic isn't flowing as smoothly.

 

[Nelsonmd]

If everyone did their part to not waste fuel by idling, we could make a difference in air quality and consumption of fossil fuels.

Hehe, you drive a 4runner dude. None of us are saving the planet or reducing our consumption of fossil fuels.

 

[theizzardking]

Don't be a baby. You'll only be cold for a minute or two. If everyone did their part to not waste fuel by idling, we could make a difference in air quality and consumption of fossil fuels.

lol, i know, i know, i can be bit of a baby sometimes, haha

What really gets me is folks who idle their cars/trucks IN their garage. Even with the big door open, air will infiltrate the house, and you'll be inhaling plenty of CO and other noxious gases. That stuff builds up in your blood and can make life ****ty for you and your kids, without you even realizing the source.

maybe they should just keep the door closed and go on for a couple of hours....do the world a favor..lol
my fav. is the people who use the charcoal bbq's to heat their home in the winter and end up murdering their whole family....dawinism....don't get me wrong i feel bad for the families but not so bad for the dad or whoever suggested to have an indoor bbq.....


and as for the cat thing, yeah your right, both of you are right, idling is a epic waste of fuel,wear, and myriad of other things, you might even consider idling entropy in of by it's self. as your using and moving all of this energy to go no where in the end, lol, i'm just saying it's not the end of the world if you do it on occasion and idling in the morning on an individual level isn't going to cost you too much cash and be too bad for your ride, it very well could be the end of the world if you look at it on a global scale though, lol


i was thinking of running an experiment next winter, buy a couple 50 gallon drums of gas in july and sit on it till January and run it for a few tanks and see what sort of millage increase i get in the dead of winter running the summer blend, I'm not sure if I'm that motivated though and how long the fuel additives already in the gas allow it to be kept for under what sort of conditions and what impacts adding something like stabulize or whatever it is called would do to the data, if someone wants to do this it would be kind of interesting................

 

[theizzardking]

Hehe, you drive a 4runner dude. None of us are saving the planet or reducing our consumption of fossil fuels.

could be worse he could be using a f-350 turbo power super stoke ultra diesel to go and get his groceries, lol , i see that all the time where i live, soccer moms driving these planet mover behemoths to go pick up little jimmy from soccer practice or to haul their ultra light river boat the 5 miles down to the water, kind of funny imo.....