Why am I getting Low MPG on my brand new 07 Prius?

I get low MPG because of:

short hops that don't get the engine warmed up,
old gas,
A/C eats up the juice.

~buttster

 

<div class='quotetop'>QUOTE(dkitts @ Jun 14 2007, 08:14 PM) [snapback]461984[/snapback]</div>

You can release the parking brake by stepping on it again. This should help.[/b]



For the poster who mentioned trying to drive as much as possible on electricity... Since there are a lot of new Prius drivers here, let me just shout... DON'T DRIVE ELECTRIC!

It is horribly inneficient to drive in elecric-only mode for anything other than creeping up at a stop light. (There are exceptions, but you will learn about them much later) Much energy is wasted in the conversion of gasoline to battery, then battery back to motion. The hybrid system is there to give more power when the wimpy engine is not enough... it's not meant to be your main propulsion.

For peak efficiency make it your goal to drive in no-electric mode (red and green arrows only) then glide with NO arrows on the screen when you are going downhill, or otherwise don't need engine power.

I could go on with a thousand other tips, and more detailed explanations, but staying out of electric mode when it is not NEEDED is a huge efficiency booster.

Next lesson: Peak efficiency of the ICE ... HINT: Don't rev it up too high, MPG = MPH is a loose guideline here.

I have averaged 56.2 MPG for the first 10,000miles on my '06, and my wife (who drives about 40% of the miles) doesn't use any hypermiling techniques. (She likes to crank the AC, and drive too fast for decent mileage)

 

Some tips/ideas/experiences I recently received here or realized myself.

1a) When having to use the engine, drive so that the MPH is never more than double than your instant mpg figure on your energy screen.
This is advice for the highway.

1b) When the engine is working your mpg should not be higher than 75mpg. If so your engine is loafing or is being used inefficiently and without need. This is the case where you want to be driving on battery (yellow arrows) and is more feasible when going slightly downhill. I believe this is known as "warp stealth" here.

1c) Even when driving >41mph there is a pedal pressure point that permits for the most efficient no-arrows state. Look for it.

1d) Look for the a orange arrow only state when driving on the engine

1e) Know your routes and anticipate when you can practice each of these.

2) Break progressively and at a constant deceleration rate to a stop so that you regenerate as much as possible.

3) Find roads with 35-40mph limit and use those for your commute if possible. That way you can use your this "no-arrow" (some call it deadband) condition which is easy for speeds below 41mph.

4) Modest hills are your friends as you can find the "no-arrows" condition more easily.

5) High tire pressure and patience are your friends.

6) Short commutes will yield less mpg because the engine doesn't have enough time to warm up and be at its most efficient. If you are looking to get more than 50mpg on a 4 mile commute you'll be disappointed.

My tanks have been getting better progressively: 45 > 48 > 52 > 54 and now it looks even better. I have an 8 mile commute, and 6 miles to the gym. I use 44/44psi and the A/C is low and set to 78 after the car initially cools down.

 

I drive mainly city streets to work and its only about 6 miles... and I basically get 42 MPG, and I was hoping it would be better... I try to drive slower and accelerate at a modest pace... maybe it takes more practice but I was hoping to get at least 45 MPG

 

<div class='quotetop'>QUOTE(YodaddyAlex @ Jun 18 2007, 01:17 AM) [snapback]463807[/snapback]</div>

What's your tire pressure? 42 is really low unless you have devilishly arranged red traffic light waves. Try and look for the "no arrow" or "cyan-arrow" conditions as much as possible and do not use the battery-only ("yellow arrow only") condition to accelerate the car from stops. Are your tires or car new? It gets better and invariably so.

 

Just got my 07 Prius Back from Toyota. Had them check it out. Having the same problem. Only I went from getting 46 MPG for 3 yrs to (for the last 3 weeks) getting 35, when I filled up and then again when I filled up to 25! They said there's nothing wrong BUT DISAGREE! They did tell me to let the GAS BAR get to 1 before you fill it up, because it has ha SENSOR that resets when it gets that low. If you fill up at 1/2 tank, the sensor wont RESET! Just thought Id throw that out there for ya.

 

PayItFwd, There are innumerable threads telling you that the 12 volt battery going bad can lose 10 MPG. I would seriously consider having it checked. (Those same threads show you how to do it your self) One easy test in the morning: leaving your foot off the brake push power and see how fast the power windows are. Now put it in Ready and compare.

The Prius does not always record when less than 3 gallons is added. By 1/2 tank you should be able to add more than three gallons.

 

The engine needs to break in as does every moving part in the drivetrain. Pump up the tires and go on a 50 mile trip consisting of city and highway. Accelerating often at wide open throttle and use the breaks to regenerate battery charges. Then go cruising at 40 MPH on some county back roads for an hour. That should set the rings and lifters and get the surfaces of the gears in the drive and electric motor/generator conditioned.

I give all my new vehicles heck when new and they have been better for it. I built a bunch of Detroit made motors and transmissions and a good break-in is essential. Babying new motors and transmissions are the worst thing you can do. Slow speeds cause low oil flow and marring in the cylinders, lifters, and on the journals of the motor. The gears need the high load to polish the contact surfaces.

 

I assume that you check tire pressures at least monthly.

Accurate no-tools battery test procedure here:
http://priuschat.com/forums/newbie-forum/73400-weird-stuff-happening-mpgs-dropping-test-battery.html