A Call to Action: MPG Meter Disclosure

Maybe the Prius MPG meter is extremely accurate, and it's the odometer that's inaccurate.

 

No, people have tested using GPS.

Even a good odometer can be off slightly if it's not adjusted to your wheels, but the factory settings are fine.

 

If the OP starts a petition on line, I will gladly sign. The error is about 5% in my car.

 

My Honda FIT was dead nuts on from the day I got it. Are you saying that the Prius is inaccurate? I just picked my up today.

 

As a group, we have found that the cons. readout is about 2.5mpg high of reality. See the sig at the bottom of my post for my own numbers over 2.7 years.

 

... and surveyed road markers. The odometer accuracy is excellent.

 

A significant part of the variation may come in where we fill the tank up to each time. The calculation by hand assumes that you fill the tank up to same point where you started on the last tank. I am sure there is variation in the auto-shut off points on the pumps. If you "top off", you are also adding variation.

I know that I could top off nearly a full gallon into my Fit. That is a 10 percent variation right there.

 

You'll see .....

REV

 

I think most folks here are finding the MFD values are running about 6% optimistic for 2010 vehicles. It's not that big a deal to me.

 

It would be nice if the readout was accurate. Mine is off 5.7%

 

I agree, and will add that how and when you fill up can add some variability to the mix.I've found that having the nozzle full open before the auto shut off can trigger a short fill, especially on warm (hot) summer afternoons when the elevated temp increases the "foaming" activity of the gasoline. Of course, this can happen if you are religious about not topping off and only fill to the first shut off. It would only take a tenth or two or three to affect an mpg calculation; made worse by a full up on a tank that is no where near empty.

I'd be curious to see if anyone from a warm climate, only filling to the first shut off, has fill-up data over the seasons. I think this would be difficult to show because the of the fuel efficiency hit during the colder temp months.

Please note that I am not implying that the pump is inaccurate (not likely with gov't controls to monitor accuracy), but rather pointing out the nature of effect of temperature on the properties of gasoline during a fill-up. There. That's my disclaimer.

FWIW, my last fill-up had 54.3 mpg on the display, with a calculated 55.2 mpg after the pump.

 

I just purchased my first prius. It's been 7% positively biased on 2 fill-ups. 47.6 actual vs 51.4 cons. I've driven extremely conservatively on both tanks and a bit surprised I haven't been able to break 50 mpg (actual).

 

Don't be so sure. There is very little government monitoring of pump accuracy. Even when required by law, the number of inspectors is very limited. In some states there is no inspection at all. With the current fiscal crisis, most pumps are inspected only after a complaint is lodged.

Tom

 

Not for me ... I fill up at the same station, same pump, with my wheels in the exact same place in terms of the concrete pad, with the nozzle hooked on the same spring coil, at the same filling speed ... low .... until it shuts off.

This is not a random thing ... it is INTENTIONALLY done by Toyota.

My computer to pump calculation has been off (high) by 2.2-2.4 MPG EVERY SINGLE FILLUP for 25,000 miles.

This is not some random thing. If it was random .... it would regularly be off the OTHER way .... not just once out of a million fillups.

REV

 

This is my first prius. It's been 7.03% positively biased on 8 fill-ups. 46.12 actual vs 49.36 comp. I've driven it like a regular car from day one and not surprised I haven't been able to break 50 mpg (actual). But the computer calculated mileage bias is a bit of a turn off for me. If the odometer suffers from the same bias is telling the wrong total mileage for the car also and warranty will expire before car actually achieves the limit......

 

Odometer accuracy had a parameter upheld by law. There is no such boundary for mpg estimates and yes pumps Ayres not guaranteed either

 

Hmmm, I drive 420 miles on a full tank, I put in about 8.8 gallons of gas, thats about 47.5mph. I'm happy, if the meter says 49.9 who cares. Its not like I need to finish and win a Formula 1 Race with 1/2 gallon remaining of gas for testing.

 

I have had our Prius for about a month now and I am seeing an average difference of about -5.8% from the display's computed fuel mileage. It seems like this is basically what everyone else is seeing. The only thing good I can say is that it is, at least, consistently off between cars.

I wish there was a way owners could go in the system and enter a correction factor or better yet have the dealer apply a correction. In this day and age there must be a way to do it. While the discrepancy is no big deal (I wouldn't get rid of the car because of it), having a feature that doesn't work accurately is pretty lame.

I was wondering myself if the odometer may be the one that was off, so I did a test. I rode 210 miles and my GPS read 209.4, not too bad at all.

 

I only have 1 fill on my tank so can't disclose too much but just wondering if owners feel as if Toyota has "ripped them off" somehow? My sticker on the window said 51 city, 49 Hwy which with the city avg. torn off can't say but the Expected range for Hwy- anwhere between 39-57 depending on how one drives. From what I have read on here on fuel consumption is that the majority of owners are getting over the estimated mpg. What is the issue. I would be upset if the majority where getting less than what Toyota expected an owner to get but we as owners are getting what is predicted.

My 1st tank dealership all pips showing. 501 miles, fill up to first click 9.041 gallons, my car computer said 52.7mpg. I had 2 pips left.

Have to go client arrived.

 

I haven't used GPS for MPH, but the gage seems quite accurate to the speed warning signs in our area. 5 to 6% optimistic CONS gage sounds about right to me too. It sucks a little.