Why am I only averaging 30 MPG??

<div class='quotetop'>QUOTE(Kathy_23 @ Jul 4 2006, 04:07 PM) [snapback]281122[/snapback]</div>

Need more info. You're in Seattle so that answers some of it but what is your daily driving routine like? How would you describe your driving style. Have you looked at any of the tips for mileage that are found on this site?

 

First thing, check to see that the parking brake is not engaged (push it on and off HARD a couple of times). Also check the air pressure in your tires. Many (if not most) Prius owners go higher than the 35/33 recommended by Toyota. I usually run 42/40 in mine, and I don't feel like the ride is overly bumpy.

As far as things YOU might be doing, you're running it in "D" and not "B", right? What is your average trip length? If you only go a couple of miles at a time, you will not get good mileage. Using the AC will also lower mileage a bit, but not 20MPG! Does you MFD say 30MPG, or are you going by the fact that you have gone through half a tank? If you do freeway driving, what is your average speed? Do you do jackrabbit starts, or do you accelerate moderately?

 

Kathy,


PART of it is that your car is new...

Most of the problem is that you need to relearn how to drive - no kidding...

Search here for the term "pulse and glide" - that will give you some tips.

You may also want to tweak your tire pressure. Many of us here use 42 psi in the front and 40 psi in the rear (pounds per square inch).

Techniques that you may become familiar with include anticipating a stop and letting off the pedal well in advance rather than continuing to accelerate almost up to the stop. Learn to watch the arrows indicating energy flow and incorporate that infomation into the pulse/glide strategy. These days what I get upset over is a tank that has an average below about 48mpg. (which usually means I'm making short drives in town on our hot summer Texas days.


You'll get used to driving the Prius, it just takes a little time to get the feel for it. Once you do, you may never want to go back to a conventional car.

Hope this helps,

Terry

 

I know that part of the problem is that your car is so new and not "broken in" per se. On that note, my car is a little over a year old, I have 5500 miles on it and I have never even come close to 50 mpg. I usually average 44-45mpg. I filled up last week and I'm only getting 38mpg. It's kind of a pain, but I like the car, so I try not to dwell on it

 

A good way to see if it's you or if it's your car that's the problem is to see if there's a Prius club (or another owner) near you, and ask someone who gets great mileage to take you for a drive in your car. If you reset the MPG on the consumption screen, you'll be able to see what kind of mileage they get. Then switch places, reset the screen again, and YOU drive the same route. If you get 30MPG and someone else gets 50MPG, then it's the way you drive. If someone else gets 30 in your car and normally gets 50 in their car, then it's air pressure/parking brake/etc.

 

There is definitely a break-in period, but my first tank (driving 400+ miles home from the dealer at the freeway speed limit) was around 47. My next tank was 50, and each tank for the next year was 49-51 (I think I drive about half city streets and half freeway). My lifetime average is only around 50, but my highest tank MPG was 58.2 (Bay Area to San Diego, freeway all the way at about 63MPH). My last two tanks since then have been 56.3 and 56.5 due to a bit more freeway driving (i.e. longer trips) and warmer weather.

Good luck in your quest for better mileage!!!

 

<div class='quotetop'>QUOTE(Kathy_23 @ Jul 4 2006, 03:35 PM) [snapback]281138[/snapback]</div>

There were lots of hints given to the guy at http://www.priusonline.com/viewtopic.php?t=8325&highlight=. My lifetime average is so far ~45.5 mpg (going by my calculations) and 46.5 if I average MFD readings. My 1st tank was my worst (maybe dealer didn't fill it up all the way or had the car idling for awhile) at 38 mpg calculated (MFD said 45.1 mpg though). I'm still working to try to get my lifetime higher.

How long are your trips? Short trips on any car will kill mileage. Are you using auto for climate control? If you are, don't. Are you using AC all the time? Also, I'm not sure if the AC turns on if you use defrost (it does on many cars), so I'd leave it off except when you actually need it.

Your accelerating w/ease might be a prob. See http://www.vfaq.net/FAQ-fuel.html.

Do you watch the MFD and stay on the screen w/the arrows? If you're on a road where you will be below 42 mph, provided you have sufficient charge, you can possibly drive that on electric alone. Accelerate up to speed and let off slightly to get the engine to shut down and either maintain speed w/the electric motor or pulse and glide. You should only do this where it's safe w/few/no cars and pedestrians around.

When coming to a stop, do you coast and brake lightly to take advantage regenerating instead of engaging the friction brakes?

 

1. What MPGs does the display show? As mcbrunnhilde wrote, the fact that the gauge reads half full is nearly meaningless; the gauge is not at all linear.

2. Remember that, when the last bar on the gauge starts flashing, you must buy gas. (Sorry for the digression, but new owners often falsely assume that they have at least 10 or 20 or 50 miles of gas left in the tank at that point. The gauge is not linear but it *does* know pretty well when the tank is nearly empty.)

 

Hi Kathy_23,

A few questions were asked. You really need to answer them for people to be able to give you responses that are specific to your situation. The mileage question is so broooaaaadddd that you are going to be swamped with the possibilities and never get at the actual problem(s).

Based on your comments so far - accellerating with ease can mean allot of things. But if you accellerate with ease based on what I think that means for a standard car, you may not being doing the best for your mileage. Standard cars have a technical thing that results in better mileage if you push on the gas pedal slowly. The Prius is somehwat different. You should be able to get up to 60 mph in about 20 seconds without negatively effecting your mileage - it actually might help it! If you take a minute to accellerate to 60 mph, you will be using the engine at such a low level it will probably be at too low a power level to be efficient. Of course if you see a red light ahead, it does not make sense to accellerate much at all. Accelerating at a low power level is poor for mileage when you are going to be at speed for more than 3/4's of a mile or so. There is more to this (yelow arrows etc) but for now just accellerate at about 1/2 the vehicle's capability.

Forget about "pulse and glide" for now - that is an advanced topic. If your trip lengths are 20 minutes or more, and less than 70 mph (but only breifly up to 70 mph) in summer weather (55 to 85 F) you should be able to get around 50 mpg using cruise control and a pulse and stealth city/surburban side street technique. But you should be 42 to 48 mpg just using the cruise control above 42 mph. Once you get to this point then you are ready for the pulse and stealth, and then pulse and glide.

If your trips are at least 30 minutes long, are using the car for comutting and do not exceed 65 mph, you should eventually get the car to perform at around 55 mpg in the summer weather after the car is broken in.

To test the car independant of driving technique, get on a level highway and set the cruise control at 63 mph. Reset your MFD screen mileage and run for several miles. You should see around 50 mpg or better when the car is all setup, broken in and working well, and no power robbing accessories are running and in summer weather.


Now for the questions -- you need to answer these!

What is your trip length ?

Is the weather really humid and cool there - are you using the Defroster continuously? The defroster tends to keep the engine running to provide warm coolant for the defrosting action. If the defroster is not needed, turn it off. This is most noticable at a long stop light after the car has been running for a few minutes. If the engine is not shutting down after about 15 seconds, there is some heat/power demand that is responsible.

Alternatively is it real hot, or are you setting the AC to 60 F when its 85 or more outside ? Take some time to study the manual on the enviormental controls. Its confusing to know what one has set the car to do until you get used to them.

Have you checked the oil level ? It should be about 1/16 inch (plus or minus 1/16 of an inch) below the high intentation on the dip stick. People on Prius Chat say to stay below the high indetation.

What were your tire pressures set at initially ?

 

<div class='quotetop'>QUOTE(Kathy_23 @ Jul 4 2006, 06:35 PM) [snapback]281138[/snapback]</div>

I bet you typically drive approximately 5 minutes or less at a time.

Take a longer drive, say 20 minutes or so, and then look at the "Consumption" screen (before turning off the car). You see a bar graph showing your MPG for each 5 minute period. You will see that the first 5-minute bar is about 25 MPG, maybe as high as 35 MPG, and the rest are well above 45 MPG.

The low 1st bar is due to the engine warmup period. If most of your trips are around 5 minutes or less, then the lower MPG during the engine warmup is going to dominate your average. The longer your trips are, the better gas milage you will get because the percentage of your total miles that are driven during the warmup period will be less.

 

Personally, I think the entire notion of car break-in is overated. Driver break-in -- I have seen a lot of

Until OP answers the questions, no practical advice is possible.

 

All of the above are excellent suggestions. Remember that you also need to COAST a lot to get awesome gas mileage. Coasting meaning that you need to let go off the gas and let the car... "coast" or stroll until the red light.

 

<div class='quotetop'>QUOTE(Kathy_23 @ Jul 4 2006, 03:35 PM) [snapback]281138[/snapback]</div>

A good article to read is "Why don't I get the EPA Mileage?" It explains the factors that effect mileage.

 

<div class='quotetop'>QUOTE(Kathy_23 @ Jul 4 2006, 06:07 PM) [snapback]281122[/snapback]</div>

Don't go by the first tank. Period. Number one, they not have filled the tank all the way, which could explain why you read a half tank at 150 miles. Go fill it up again and reset the trip A and/or the MFD screen and then see what happens from then on. Record your odometer reading (not just the trip) and how much gas you put in at every fill-up, and do this diligently. Omitting that first tank, divide the total miles driven (minus this first reading) by the total gallons used (that you know about) to give your lifetime MPG and then report back in a few tanks.

 

<div class='quotetop'>QUOTE(Kathy_23 @ Jul 4 2006, 05:07 PM) [snapback]281122[/snapback]</div>

I'm still on my 1st tank of gas with 380 miles and so far the MFD says 46. This is in 110 degrees with the air blasting, rolling hills and most trips under 12 miles long. I am happy as can be. Will take my 1st road trip on the 15th and by then I should have my break in miles over and can really step on it !!!!

 

<div class='quotetop'>QUOTE(B Rad @ Jul 5 2006, 04:23 PM) [snapback]281632[/snapback]</div>

I'm close to this....still on 1st tank and showing 47. I know I still have lots of driving finesse to learn, so I'm looking forward to further improvement If only it weren't for my 5x/week trips to the gym, that is only 3 miles each way...but unfortunately the route is NOT safe for a bike.

 

I remember getting 30's on my first tank, but I'm consistently getting around 50 now that I have passed the 5,000 mile mark. It takes awhile to break it in.

 

I have a lead foot and just LOVE the mileage my Prius gets w/o driving any differently than I do in my other vehicles (including 2 American-made gas guzzlers -- a Dodge Durango V8 and a Dodge Ram SRT10 -- which get only 14 and 10 mpg on the freeway).

I bought the Prius specifically to save gas on longer trips (over 50 miles roundtrip) that have just gotten too expensive in my gas guzzlers. I obviously could get better mileage if I changed my driving habits a bit, but I'm not obsessed w/getting better mileage. I think the gas mileage that I'm already getting is fantastic!

I drive the Prius consistently between 70-80 (which is my cruising speed on the freeway) and usually get 40-42 mpg. I've only got 800 miles on it so far, but didn't notice any difference in the mileage from the 1st tank of gas to the last. I have noticed a distinct improvement in gas mileage when the AC is off, but I like AC and use it even when it's not that hot. Even so, I still get 38-40 mpg when driving FAST w/AC on and 40-45 when driving slower w/o it, which is about 3-4 times better mileage than I get in my gas guzzlers. B)

However, I have also noticed that the on board computer computation of the mileage doesn't seem all that accurate. It's about 3-5 mpg higher than my actually fill-up computation. Has any one else noticed this discrepancy?