Really bad gas mileage on 07

Also be aware, most Prius posters live where they really don't get winter. Sure, they call it winter, "OMG it went below freezing and there was snow and ice!" That's not winter. When you get in the car and the seat doesn't give because it's too cold, THAT's winter!

Yes, this winter has been rough to start with in our area (I'm about 1000 km north and 500 km east of you). Your car will probably have to learn how to operate in your environment as well, and that usually takes a few weeks.

Now, the anti-Prius (see below) is getting about 17-18 l/100 km in this weather (and I don't warm it up)! That's almost 2 1/2 times the fuel use you are seeing. I used to have a Subaru and it didn't do a lot better.

I suspect the two things that are killing your mileage from expectations are the warm up and the short trips. It takes 10 min of driving to fully warm up a Prius in these temps. The car is just getting nice and warm when you shut it off.

You need to:
1. Get the block heater - email [email protected] to order it. Your dealer can install it for you. You can certainly ask your dealer if they can get you one - they are far enough north that they should know about them.

2. Consider blocking off the air vents at the front of the car. Jay in Winnipeg used the black water pipe insulation (foam plastic). Just cut it so it can be wedged into the slots. This greatly improves warmup in severe cold. Be aware, if there is a warm spell, you will want to pull these off the car. It's easy to install/remove them so that shouldn't present a problem.

The issue here is the car is so efficient it doen't generate a lot of "waste heat" so you have to make good use of what's there.

 

Another thing to realize that the Prius derives much of it's fuel savings from turning off the engine at traffic lights, and while cruising at steady speeds or down hill. However, in the winter time, the driver tends to want to use the cabin heater. The cabin heater uses engine heat to provide warm air, and in order for the engine to warm up to a temperature sufficient to provide cabin heat, it has to running.

The result of this is that instead turning off the engine at the first traffic light or stop sign you come to, it instead leaves it running at a fast idle. This will continue for 10 or more minutes, depending on how cold it is. And during this time, it gets gas milage similar to an normal economy car. After the engine warms up enough to provide cabin heat even with the engine off, it will start acting more like it does in the summer, and shut down the engine when it doesn't need it, and it will get much better gas milage.

So, if it takes a significant portion of your trip to warm up enough to shut down the engine when it doesn't need it, or if you just let it sit idling in the driveway for a half hour burning gas without going anywhere, then you will get gas milage approaching that of an economy car.

As a point of reference... Both my wife and I have each have a Prius. I drive 20 miles each way to work and I get around 50 MPG in warm weather, and as low as 40 MPG in really cold, 20 degrees or lower, weather. My wife does mainly short local trips of a couple of miles each. She gets around 40 MPG in warm weather and as low as 30 MPG in really code, 20 degrees or lower, weather.

 

I think it's a little early to jump to conclusions about mileage. For one thing, the dealer could very well have put in enough gas so it read full, but wasn't topped off. You should get a good 50 miles before the first "pip" disappears. Since you only drove 200 miles on that tank, a small fluctuation in filling levels could make a big difference. My worst gas tank ever was the tank that I drove home from the dealer with, and that was with only 3 miles on the odometer. But I guess it needed to warm things up and charge the battery and who knows what was done in those 3 miles and how long they may have had it warming up on the parking lot while I was signing paperwork.

Put in a couple of your own tank worths, and see if it doesn't improve. Like people say, the cold weather is also a big killer. Think of trying to start your old car in below-zero temps, that's when the battery is the weakest. So not only is the engine less efficient, the battery is as well, so it gets a double whammy.

You're right about the heater being weak. Block heater would help, but a less expensive approach is to partially block the radiator (winter front, I think they called it in some recent posts).

There is another thing you may want to reset other than the trip meter - in the consumption screen, there's a reset button on the bottom right. It should automatically detect when you put in more than 3 gallons and reset itself, so that the average mpg computed is for that tank only. But it may take a couple minutes to detect that change, so I always press the reset button on the screen as well to be a bit more accurate. It's not really needed though, and as people say, the computer-generated mpg number is a good estimate, but not terribly accurate anyway (maybe +/- 5%, usually on the plus side).

The good news is, this should be as bad as it gets, which is still better than your '95 Subaru (even with the same mileage, it will be producing less CO2 and other pollutants, due to other engine improvements). The break-in period helps (the first oil change seems to coincide with an increase in mpg, but synthetic oil alone has a pretty minor effect), learning how to drive for a hybrid, particularly how to glide (watch the energy flow screen). Use the battery as little as possible, gently accelerate and coast at high speeds, glide at low speeds (<40) whenever possible. If the snow is causing stop-and-go traffic, the need to constantly accelerate and quickly brake can be a killer on mileage as well.

After the first 5-10 minutes of driving, your consumption screen should show something close to 50 mpg on the 5 minute bars. If it's doing that, then it's just the shorter trips, your warm-up habit, and cold temps causing the problem. If it's not doing that, the problem is either with your driving habits & conditions or possibly something with the hybrid system itself.

We're not terribly alarmed and blaming Toyota or the hybrid system immediately because I think we've all seen mileage like that for at least short periods of time. Give it a little time, don't jump to conclusions, it can change seemingly randomly from one day to the next until you start to see all the inputs that affect it. I think that's why you've seen a lack of sympathy here. You may think it's terrible and outrageous but we've gotten a little sensitive to complaints from impatient people or detractors about not meeting the EPA estimate (not that that totally applies to you). The Prius rewards the patient.

 

I got my car this past April, so it was nice weather. My first tank I got 43 MPG. By the second tank, I was up to 49, just from learning to anticipate stop lights, etc.

Another think that affects your 'first tank' mileage is how 'full' the dealer filled it. I know mine was completely full, because the salesman drove me over to the gas station across the street from the dealership and had the car 'topped off' - we don't have 'self serve' in New Jersey, so it was filled by the attendant.

But just because a car gas gauge reads 'Full' doesn't mean it's full - the dealer gave me a loaner car when I brought the car in for service and I was supposed to return it full - I put 40 miles on the Camry and it took 4 gallons of gas to 'fill it up' before I returned it!

 

<div class='quotetop'>QUOTE(Prius happy @ Nov 30 2006, 04:59 PM) [snapback]355938[/snapback]</div>

back in the day that was understood :lol: some of us waited many months to get our prius!

just hang out on the site a bit and you'll see posts about pretty much every common issue.

and hey, welcome and congrats on the new car!

 

:lol: Sorry, Prius happy...

I had no clue as to your gender. I'm confident you will discover how to enjoy your Prius. There is a 'learning curve' to becoming accustomed to the Prius peculiarities. There are MANY suggestions in PriusChat which will be helpful to you. Although it's poorly Indexed, the Owner's Manual also has helpful information - not like reading a pulp novel. I make a habit of making my own "Index" in the back when I find helpful information I may want to access again, either for my own information or to post on PriusChat to help others.

 

<div class='quotetop'>QUOTE(Prius happy @ Nov 30 2006, 12:50 PM) [snapback]355757[/snapback]</div>

Unfortunately, It's well documented that the Prius MPG suffers in the cold weather. Actually, ALL car MPG numbers suffer a great deal from cold temperatures and winter-cut fuel. I'm afraid that the beginning of winter is the wrong time to buy a Prius and expect to get close to the Manufacturers Suggested MPG figures.

I bought my 2006 the 5th of September. My first few tank fulls were mid 40's (MPG) while it was beginning to "break in". My next 6-8 averaged almost 54MPG....but now that it has started to turn a bit colder up here, I have noticed my mileage start to drop. I keep strict mileage/fuel usage figures and that's what I figure my mileage with, not the computer readout on the dash. My milage has dropped to almost 52MPG now, but it has been unusally warm up here this fall. I expect much lower MPG to come.

My opinion is that if you want realistic mileage per gallon displays on the MFD screen, then DO NOT reset it every fuel stop, just let the computer average it tank to tank. I just clicked over 5400 miles and my MPG calculations using actual miles driven/fuel used are very close to what the car is figuring. Within a mile or two per gallon.

Don't be too hard on the car. It is a great car and is worth owning for the long run. Unfortunately (again), it seems that you have almost exactly the wrong mission for the car to get its best MPG (especially during cold weather). 30 mile average trip (15 mile legs) means that half the first leg (7 miles or so) the car is still warming up and getting rotten mileage. Then you get to your destination, probably stay for a while (work, shopping or whatever - and the ICE cools) The you drive home and again probably a good deal of the first part of the trip is warm up/bad mileage.

Hang in there and try to roll with it. This time next year I'll bet you will have a different view!

Good luck.

 

One more thing ... if you're lighting the "slip" light that often,
you probably want to read and heed
http://techno-fandom.org/~hobbit/cars/mpghints.html
.
And really, it's *all* about heat! About two-thirds of that gasoline
energy you can't recover under *optimal* conditions, let alone when
introducing any more losses into the system. Get off those brakes,
bundle up and set the cabin heat for 66 degrees with low fan, buy
the block heater, take off gently very soon after startup, etc etc.
.
_H*

 

<div class='quotetop'>QUOTE(Tideland Prius @ Nov 30 2006, 02:35 PM) [snapback]355954[/snapback]</div>

It ain't the heat...it's the terrain down there. Most of my driving is short trips in my hilly town, so I average about 43mpg. I get closer to 50 on longer trips, especially when I don't have much terrain to climb.

We're lucky here when it comes to climate. Our average annual temp is 59F (15c) because I live right at the edge of the Pacific. Temps here this week have been a bit below 40F (about +4c) at night, which, to the northern folks here, are laughable for winter. Folks in Alberta probably just switch from shorts to trousers at that temperature.

 

Gas mileage always suffers in cold weather. For that matter, so does EV mileage, for those of us that have EV driving experience. Cold is murder on batteries, even Li-ion ones from what I've heard.

My PHEV is starting to suffer the effects of mid-western winter blues. My current gas tank mileage just dipped below 70mpg. That stinks! (I'm shooting for 75+ mpg)

 

Temps these past two weeks have been in the -10 range here in AK. I got barely 30 MPG on my last tank. I plug in my block heater and turn it on for at least 3 hours before driving, but it still takes about 10-15 minutes of ICE runtime before it will dislodge the hard frost on the glass enough for me to scrape it off.

The ICE never shuts off on the way to work, and I have the fan speed on medium, 65 degrees. I'm normally less than 10 minutes from work when the heat actually gets hot.

Cold is a mileage killer.

 

<div class='quotetop'>QUOTE(Jim B. @ Nov 30 2006, 08:07 PM) [snapback]355976[/snapback]</div>

While this would provide you an accurate life-time MPG average, after that many miles the averge MPG value will become so stable as to be useless.

For instance, lets say you've averaged 50 MPG over those 5400 miles, and then you get only 10 MPG for the next 100 miles (a full tank at 10 MPG). At this point, your average MPG would show 49.3 MPG. After the next 10 MPG tank, it would show a 48.57 MPG average. The accumulated weight of all of your previous miles dominates the average and new values have little impact. You would have to travel another 5000 miles at 10 MPG before your average got as low as even 35 MPG.

I think is far better to just reset the MPG average every tank and ignore it for the first 150 miles or so. At that point, it starts to stabilize and by the time you need to fill the tank again, it's a fairly reliable number. If you want to keep a lifetime average, just log the miles and average each time you fill up and calculate the lifetime average manually.

 

<div class='quotetop'>QUOTE(Charles Suitt @ Nov 30 2006, 03:11 PM) [snapback]355857[/snapback]</div>

<div class='quotetop'>QUOTE(Charles Suitt @ Nov 30 2006, 03:11 PM) [snapback]355857[/snapback]</div>

You mentioned thermos keeping coolant hot for over 24 hours. Where did you get that info? That is great news because it means, since I garage my new Prius, that I need not worry about starting to drive in the morning with a cold engine. I am a new, first time Prius owner, so I am on a steep learning curve.

 

As others have posted, the number one thing to avoid for best mileage is: idling. Whether letting it sit to "warm up", or just idling at a stop sign, idling the engine kills your mileage.. Why? Well, your "mileage" is actually "miles per gallon", or in another sense, how much gas you've used to go a certain distance.. If you're idling, you're using gas up, but going nowhere..

For best winter mileage, simply start up the car and drive off. Do NOT let it sit and "warm up" at all. For the interior climate control, do NOT crank up the heat; set the system on "auto" and keep the temperature dial at something reasonable (on my Canadian Prius, I have it set at a notch or two past 25 C). Wear an extra sweater and a hat and gloves if needed, but resist all temptation to turn the temperature up to max because that heat has to come from the engine, and if you ask for too much heat, the car will keep the engine running at all times (and thus, killing your mileage- see the note about idling above) to provide you with heat.. If it's really cold in your area, you may consider getting a block heater installed- this heater is plugged into the AC mains and keeps your engine block warm so that the Prius will go into it's most efficient operating state sooner and allow the engine to shut off at stop signs, etc. Another thing to consider that has also been mentioned is to block off the radiator (basically you shove something in front of the radiator to keep the cold air from cooling off your engine too quickly; I have a sheet of coroplast that slips in front of the radiator (it just slips in on a Classic Prius; on an HSD, you have to take off a plastic cover first), and I have a hood liner of that foil-lined bubble wrap insulation that velcros on the inside of the hood).. If you follow these suggestions, you'll find that you can get very good winter mileage on your Prius..

 

<div class='quotetop'>QUOTE(Prius happy @ Nov 30 2006, 12:50 PM) [snapback]355757[/snapback]</div>

This is another relatively minor factor that will detract from your mileage that nobody has mentioned, aside from hobbit mentioning that braking is bad for MPG... The Prius has regenerative brakes, which means when you push the pedal it does not normally use the brake pads/rotors ('friction brakes') to slow you down but rather acts as a generator and puts energy back into the battery rather than wasting it as heat.

Under 'normal' stops, the friction brakes only kick in right before coming to a stop. HOWEVER, in an emergency stop situation (i.e. ABS firing away), the regen braking is canceled and you go straight to friction braking, so you are wasting the energy that is normally recaptured, like an old fashioned car!

That's the way I understand it, anyway.

This is likely a relatively minor loss in the grand scheme of things (much less that warming up the car!), but is just another factor among many in the "MPG worst case scenario" you described. :huh:

I suspect there is an energy loss associate engaging the traction control as well, but perhaps someone more versed on that feature can explain it.

BTW, for how many minutes were you warming up your car? :huh:

 

While the car can be driven immediately upon starting even in the coldest weather, there is a temperature below which it becomes intolerable to sit in the car. When I lived in Fargo, ND, I let the car warm up if the temperature was colder than 15 below zero because, no matter how warmly I dressed, it was painful to sit motionless at that temperature. My first tankful in Fargo in January, 2004, was 29 mpg!!!

Another mpg issue is the battery temperature. If your car sits outside in bitterly-cold weather, the battery will be so cold it is almost useless for the first 10 or 20 minutes of driving, and you'll get lousy mpg. Ideally, for cold climate, there should be a block heater to warm the engine, and even more importantly, a battery heater to warm the traction battery. You can buy a block heater. I know of no battery heater available.

(The Tango EV, built in Spokane, WA, has a heater that keeps the battery warm any time it is plugged in.)