Can't get it to read over 38mpg avg.

First off, make sure to reset it. Since you just bought it, shuffling around dealer lots makes the average real low to begin with.

Also are you running the cabin heater? You might want to get the mpg survey questions and post them here. That is a good start anytime.

 

The only way to get heat is to run the engine. So times when the engine should be off, it is on wasting fuel just to make you warm.

 

Scott,

Welcome to PriusChat.

Tell us about your driving style and your commute.

Do you still have your '06? How long did you owned it? What was your average mpg with the Gen II?

 

Beware...a small sample distorts the accuracy of any mileage reading.

One action you can take is to turn the heater completely off when you start out until you know the heater is going to be warm just because the ICE has run long enough.

My impression was I got EPA-like figures when the weather was warm, the ICE has been shutting off, I was in ECO mode and I was being super conscious of keeping the power gauge below the middle. Once I got 4 tanks in and became more comfortable with the car and stopped paying as much attention to the gauges, and once it got cool enough that I wanted to have the heater on from the start-up, my mileage dropped about 3 MPG even in ECO. It is 17F out right now. I'd get poor mileage now...relative only to what I'd get if it were warm. But relative to other cars ...

Use fuelly to track your mileage and let the tank get to around 1/3 full so you get a sufficient sample that the pump sensor variation on when to shut off doesn't distort the figures. All I do is write the mileage on the receipt and enter when I get home. I could use an app for that.

 

A more manual alternative to fuelly is to track total gallonage and mileage.

Calculating miles per gallon on a per tank basis relies on using the tank as your unit of measurement. It holds X gallons and ideally you full it up to full at X gallons. But it holds X gallons, Y gallons officially where Y << X, and the pump stops it somewhere between Z and X where 0 < Z <= X. Each pump is different, and on the GenII the bladder complicated things more. You don't have that, so it is more or a normal tank, but you will still get huge variations. So the larger you make the delta to fill, the random pump errors tend to sift into the noise. But you will still get variations in MPG even if you got the exact same actual MPG just because there is error and are differences.

So what you can do is right down total miles driven on total gallons used. Now your pump error is factored over hundreds of gallons instead of 8-10 gallons, pushing it way into the noise.

So today you are at say 500 miles. In a couple months, you may be at 6500miles (6months @ 1k per month). If you go to fillup after 400 miles and put in 8 gallons, and all your other receipts total up to 122 gallons, then you used 130 gallons to go 6500miles, or 50mpg. If the pump put in 8.2 gallons, then it would calculate as 49.92mpg. 7.8 gallons would be 50.07mpg. If you calculated it per tank, you would get 48.7mpg to 51.3mpg.

I recommend tracking both. If you get a tank that is way too low, you can spot a problem early. But take it as a generalization with a huge boulder of salt and wait for the total mpg before jumping to conclusions after a couple mpg difference.

 

There are a lot of interesting videos on YouTube about effective driving strategies for the prius. I found these helpful.

 

Fuelly is the best tracking tool. They have an app for iPhone. You enter info at the web site and view on iPhone. Many graphs and data. You can see the banner on some people's posts like mine.

 

Alternatively if you put the heater in Auto mode, the blower will not kick on until the engine has warmed up enough.

 

Scott,
Putting aside any mechanical issues, the cause is just what you wrote about in your complaint. The colder temps. cause the engine to run more often. The reason for this is that you probably turn on the heater in the morning to heat the cabin of the vehicle, and the engine is required to run in order to raise the coolant temp. to provide you with heat. ALso, the climate control's defroster requires that your compressor be activated, which also requires the engine to run.

I too had this complaint when I first bought my Prius. The service tech explained this to me. To prove my explanation do this. When you stop at the first traffic light in the morning turn of the heater. If you don't encounter any traffic lights, just safely pull over and turn off the heater and I'll bet you'll notice that the engine stops running. This is the normal operation of the climate control, engine, and the car's computer all working together to provide and maintain heat for the inside of your vehicle.

I live in St. Louis MO and right now (Feb.) I'm only getting 36 mpg. This is down from 42 mpg that I was getting during warm weather.

John R.

 

This technique won't avoid engine idling--it will simply turn on the fan once there's some warmth. That in turn will encourage the engine to run to meet the demand from the heater.
Driving to work with my hair damp and the weather cold I far prefer to select windshield & floor mode with the fan on one bar and the temp initially at LO. This will keep the windows clear but will also allow the engine to shut down as early in the cycle as possible.
My car will typically do an engine off coast within the first 2 miles on a morning in the mid 20's F with this technique.

 

At least where I am, it is starting to warm up again, and my v is getting better MPGs. Spring IS coming.

 

I always wondered where in the world The Groundhog thought spring would start by mid February

 

The daffodils are blooming, it is considering being Spring.