poor mpg

Bluejay...

Double check that your PARKING FOOT BRAKE is fully released. Press it all the way down for the PARK BRAKE ON position and then press it for FULL release....be sure that it has released completely to the top of its travel!

I know this may sound stupid but I rode around for half a day wondering why things didn't seem right with the Prius until I realized that the FOOT PARK BRAKE was depressed about a quarter of the way down. My, MY, the performance was so much better with it off!!!!

Good luck.....Tom

 

I had the same thing up until the last oil change when again it was slightly overfilled. Had to remove excess using the turkey baster + plastic tube trick in the dip stick hole. Also increased the front tire pressure to 42 and the rear to 40 and the combination increased my mpg by 7 miles/imperial gallon. Still cannot figure out why our mpg is greater on the highway using cruise quite a lot as opposed to in-city/town driving.
Gary

 

16 mpg sounds way too low unless you're driving under 1 mile in heavy traffic. 16 mpg is probably way to low for many conventional non Hybrid cars and some SUVs. I live not far from Philadelphia and in suburban driving I've been averaging 40 to 45 mpg during the same time. The worst mileage I ever got was when it was about 14 deg F and I drove hard and drove under 6 miles total. Then I got 29 mpg.

So the parking brake sounds like the only logical explanation.

You should start to learn a little about how to coast on a Prius. After you accelerate to a desired speed, lift of the gas, watch all the arrows point back to battery, then press the gas just enough to get all arrows to disappear. On a level road or slight declines you'd be surprised at how fast you can coast with the display showing 99.9 mpg. A benefit of learning a bit of the above, other than getting better gas mileage, is that you'll better be able to diagnose what is wrong with your car if the mileage seems unusually poor. The Prius computer display does a good job of telling you how hard it's working and whether the gas engine is on. The instantaneous mileage meter is pretty accurate. If you get poor mileage, especially as bad as 16mpg you should see the impact on your instantaneous mileage meter. So if you ever find the gas engine never turns off or if it seems your car isn't coasting that easily then these are some clues.

 

Bluejay, I get under 10 MPG. But only first thing in the morning with a cold engine, going up a hill, and only for 100 yards. How many miles were at 16 MPG?

The instantaneous MPG readout can be deceptive. On the highway I've seen it drop below 20 when I gunned it to pass, but the five-minute segment was over 50 MPG.

If you've gone miles at 16 MPG, something is definitely wrong. If it's not the brake (easy to hit by accident) then you need to take it in to the dealer.

Oh, BTW, welcome to PriusChat, too bad this had to be your first post.

 

The only time I had a sudden drop I had low pressure in one tire. Filled it never figured out why. Maybe I hit a curb. I would check you tire pressure.

 

Is the advice about not using the defroster limited to front, back or both?

 

Well.. i don't see a location on your info..

Have you thought about cold weather? Leaving defrosters on will kill mpg.. like.. kill it.. very badly.

I personally would rather dress warm, and not have the heating system on.. or.. on low. try not to use the defrosters. it drains that battery pretty quick. It also keeps the engine on.

 

For my first 5000 in San Diego county I was getting 40-41, now that I am at 6000+ I have gotten up to 43-44 for my last three TANKS!
1. I am going 65-70 most of the time
2. I am keeping an eye on the tire pressure
3. I keep the AC at 72 most of time
4. My car wont even move with the parking brake on but if you use the engine brake you will definitely decrease your mileage.
5. I rarely use CC
Any further input from bluejay??

 

Really good advice above.

Presuming you are not driving with all the warning lights lit, the engine is probably ok, and you have a whole lot of unwanted friction somewhere.

Stuck tire brake ?
Partial handbrake ?

Just saw your last post. Perhaps you should try something of a standardized test: Try driving for about 5 minutes, and then go out on the highway and see what a five minute bar is with cruise set at 50 mph. If ambient temperature is above 40 F, mpg below 50 would be reason to think a problem with the car is present.

Good Luck. I expect this will get solved.

 

I would also recommend a more reliable tracking method. I find that filling up the tank can vary alot depending on what gas station I fill up at. Try using the same place. The "bars" are not that reliable (as with most cars) for determining gas mileage.

 

We had a poll on brands of gas with some good discussion at

http://priuschat.com/index.php?showtopic=13054&hl=chevron