poor mpg

I live about 30 minutes away from downtown Philadelphia. I've gotten about 40 to 45 mpg for my overall average.

I've driven in downtown Philadelphia during heavy traffic and I could believe you getting between 25-29 mpg these past few weeks if you drive only 6 miles. Since you claim it takes you 15 - 25 minutes to travel the 6 miles you are definitely stopped at traffic lights quite a bit. So if you have the heater on especially in the very first 5 minutes your going to be burning up gas while while standing still. During the first 5 minutes I would always turn off the heat, unless your are moving. As soon as you are stopped at a traffice light, turn off the heater. As soon as you start moving again then turn it on. The goal of turning the heat off is to stop the gas engine from running when you aren't moving. You're worst gas mileage occurs when your gas engine is burning and your car is not moving. Of course you could elect to always keep the heater off, but personally, I'm one of those whimpy drivers that kind of likes to keep my toes warm.

As to the impact of cold weather one thing that does sound a bit inconsistent and possibly troubling is that these past couple of weeks have been relatively mild. In the Philadelphia area the coldest weather occured in late November and early December. So I can't attribute your mileage drop from the cold weather. It appears you're kind of like me in never having yet driven a Prius in very warm weather yet.

Your claim of 16 mpg is now a bit more questionable as you describe trying to get your average mileage for the 6 mile drive from work back to home. Does that mean you go to the "consumption" screen and really reset your average mileage read out at the beginining of every drive? If the answer is yes than that 16 mpg average is pretty accurate. If you are using the bar graphs on the consumption screen that show the average mileage over every 5 minutes then your calculations are not mathematically correct. It's true that the most accurate way of judging mileage is by trying to measure the exact amount of gas used up from the gas tank. However, in lieu of doing this, the average consumption readout is pretty accurate. I've heard of no case where this read out is way off. I have heard of many cases where trying to measure gas used from the tank is way off because of the inconsistent way the Toyota Prius tanks fill up at the gas station.

So after saying this if you still claim that the 16 mpg average represents the 6 mile drive home in weather during these past two days, then I'd think possibly your parking brake was partially on. I'm trying to imagine what kind of driving I would have to do to coax my Prius into getting 16 mpg average on a 6 mile drive and it actually kind of sounds challenging to do. If I floored my Prius and drove like a maniac I'd probably average in the 20 mpg range because my Prius would be moving too fast to get low mileage. However, if I turned my heater up to maybe 70 degrees F, let my Prius warm up before ever drivingl, and always tailgated the car in front of me to prevent any other car from merging in front of me, and was always caught in constant stop and go every 100 feet, than I could start believing getting 16 mpg.

That does bring up one point. Don't ever bother trying to warm up your Prius engine. Just buckle up, press power and drive immediately. Don't wait. The waiting will devastate your mileage. All cars get 0 mpg when they burn gas and aren't moving.

 

A block heater sounds like a very good mod for you with your commute conditions.

 

bluejay, you didn't mention checking your tire pressures. You really need to do that when the daily average outdoor temp changes by 20 degrees F or so, or at least monthly. Do not drive more than one mile in the hour before you check pressures (after sitting all night and before starting the day's driving is a good time).

 

I '"solved" my poor Prius mileage. I leave it parked and will drive the Corolla until spring and warmer temps come around. I'm not able to get over 32mpg on a 100 or so mile drive. My Corolla gets 35. Tonight I should get out the manual though and see if I need to disconnect the battery or something. And I never had the cabin temp over 65, don't drive with the defroster unless I really couldn't see, and the air pressure is fine.

 

There's something wrong with your car if you can't break 35 MPG on that kinda drive. Hell, if you cant break 40 MPG there's something wrong. I can get 46MPG in 0 deg F weather on the highway with the heater on a moderate setting and temp about 68.

 

Sounds like you have already made up your mind. It would be nice to know what part of the world you are from though?

 

Not quite. It is miles driven/gallons used during those 5 minutes. It doesn't matter if you don't move during part of those minutes, as long as you don't burn fuel during your standstill. If you were burning fuel during those 4 minutes, then yes, your 60MPG will diminish at the rate depending on the amount of fuel used during those 4 minutes. Without knowing how much fuel was used, you can't say what the 5 minute bar would show. Heck, I don't even know how much fuel was burned during the first minute, since I don't know how many miles were travelled. Therefore, there's no way to say what the MPG would show for that bar under your scenario.
However, I can tell you that if you were stopped during those 4 miles and no fuel was burned, it would still read 60MPG. You can drive one foot in 10 seconds on EV and never move for the rest of the 5 minutes, and it still will read 99.9 MPG.

 

I live just across the river from you in New Jersey, so the weather is about the same. My MPG dropped off a little with the colder weather from 50 to 53 MPG range in the summer and fall to the 45 to 48 MPG this time of year.
Sounds like there is something wrong. I would take it to the dealer and it your dealer won't or can't fix it. Take it to Runnemede Toyota they have given me the best service.
Happy New Year

 

given you only have 1800 miles on the vehicle, you ultimately will see a mpg jump in and close to 5000 miles, then an increase around 10000miles+/-...in the dead of winter, here, we are seeing 32-41mpg depending on traffic...however, i keep saying to myself, if i was driving any other car...it would be getting 12-15mpg if your lucky,even though the epa rating is 20-25...so i would give it time, and of course, you are still in a learning curve on driving more efficiently...i would venture to say, drivers in philly are absolutely clueless on how to drive efficient...jack rabbit starts to race to the next red light, as they do, will get you 5-10mpg in any car...also running 75-85mph on the freeway will kill mileage as well...i would go through another few tanks before i would take it in and see if you can average it out ...unless there a problem of fuel and the engine not running at efficiency, i know the toyota techs are going to say there is no problem and its user error, so to speak...after 37000miles here in the cold midwest, i average 38 in the winter, and 51 in the summer...+/- whereas, the non-hybrid car averages 12 in the winter and 18 summer...EPA(20-25)
if the general population just knew how poor there mileage is, there would be an outcry which was never seen before in this country...no cars are getting epa numbers...

 

few cars is probably more accurate, if you are considering lifetime mpg. In nice weather at 55 - 60 on the highway, or in not horribly congested city driving, the great majority of people hit EPA. Otherwise, I very much agree with your post.

 

If you do a search under my user name, you'll probably notice that last winter I either set or tied the Absolute Lowest Prius Winter City Mileage: 9.8 litres per 100km or 29 MPG Imperial gallon.

As you will notice, I live in Winnipeg, Manitoba, Canada. Last winter was brutal, with many weeks of -40 weather, blizzards, and Snow Routing due to snow cleanup. My commute, normally 15 minutes, stretched to 40-55 minutes of stop-n-inch torture.

My previous vehicle, a 2000 GMC Sierra SLT 4x4, got around 45 litres per 100km in similar driving conditions: around 6 MPG Imperial gallon.

This winter my fuel economy hit is much less, mostly due to the much warmer temps (0 C to -10 C). I fashioned a winter front for my Prius and that seemed to also help quite a bit when we did have that cold snap in December.

Last, as a trial to "prove" concept, I'm running Mobil 1 0W-20 as a "winter" oil. My idea was the much lower viscosity of the oil would help reduce the hit during cold motor operation.

So far, especially during the first 2-3 minutes, my instant fuel economy has never dipped below 15 litres/100km. Last winter it was 20-30 litres/100km. The motor seems a bit smoother when cold, but this is subjective on my part. I can't back it up with data.

So far, my winter city fuel economy is averaging around 5.3 l/100km or 53 MPG Imperial gallon. I do realize the much warmer temps are responsible for most of that.

I don't recommend running a much lighter viscosity oil unless you're willing to follow up with used oil analysis. I did a sample at 4,000km and the wear metals were insignificant: Fe was 4, as an example, with TBN still of 10.5.

I'll post the results of the UOA at the oil change. If the results are good I will definitely run Mobil 1 0W-20 next winter too.

 

BlueJay, ain't from up North, but just adjust to the Hybrid, check tire pressures with temp changes outside, and frequently. Coast and use the screens, only reset with a fill up, don't measure mileage by hash marks on the gas gauge. Many times I get dismal MPG outputs with the first uses of the car, due to short commutes, but over a complete fill up the story changes. I changed driving habits and have gotten better performance, keep the "creature" conforts to a minimum in cold and short trips (works with hot weather too), unless the wife is with you. Wear a coat...watch that defrost, I found that when the temp is low (ie below 65 F - or max cold setting) I set for that, otherwise the car will electrically heat up the temp for front defrost. The rear, the defrost is just heating coils trying to warm up a back window, so I avoid that altogether. Just blowing o/s air on the windshield usually works, if you need heat for defrost to get rid of the ice, use a scraper first outside, just like you used to do with the "detroit" cars..because this can can electrically heat up the air if the engine is not warmed up, so you can easily burn a lot of gas on short trips to accomplish that. In cold days and here we mean in the 30's !!,, I generally leave ventilation off if I can, for awhile letting the engine warm up..of course up North well it is colder...I think the heating settings in defrost and cabin temp is where the mileage was going, as well as the driving..so try to control and cope with the discomfort, seems like it is a short trip anyway. Good luck

 

Try rebooting, click on andyprius

 

Hello.. i just bought a used 2005 and am averaging 31 mpg on the freeway. i m very very disappointed. toyota is not offering any thing in terms of answers. i was wondering if you found a solution.

 

Most often this is caused by a failing 12V battery. Otherwise, it is caused by never getting the engine to shutoff while stopped or in stealth/glide. Please check the 12V via http://priuschat.com/forums/newbie-forum/73400-weird-stuff-happening-mpgs-dropping-test-battery.html Note that the number following the decimal point is very important, i.e. 12.0V == dead, while 12.5V == good.

P.S. what size tires does it have? Large diameter custom wheels will also cause poor mpg