Fluctuating fuel gauge

At least we don't hear the gas sloshing around like I did in my '03 Honda Pilot.

 

Please clarify - the 2010 does not have a bladder, so it's not subject to the don't every try to top off rule? That's good to know. While I don't overstuff anymore, I like to at least round up to the next whole dollar if I can.

And, as long as the tank uses a sensor in the fluid, it's subject to going up or down. Maybe the shape of the tank is a factor in making it do so more when near full?

 

I did notice an 8 -> 10 change last week, following a substantial grade change. But all my previous cars with analog gauges have also displayed significant fluctuations with slope, so this ought not be a concern.

 

It does have a charcoal canister as part of the emission control system that can get flooded when you top off. I just don't period.

 

Does anyone know if the 3rd Gen has the AZ and EL sensors like the 2nd Gen? These sensor help to correct the fuel guage. With time they'll drift off and can be easily reset.

 

I see that as a good thing.. I've gotten as much as 200miles on my GenII before the first bar dropped... although we are used to that.... its "way" inaccurate!!!

At least now we have a truer report of what the gas is doing.

As far as bars moving up briefly and back down.. I could see that too as gas slotches all over the place in the fixed container.
We no longer have a flexible gas tank that changes volume with temperature.... that too is now more accurate...many of us complained about the differences if volume the gas tank would take based on outside ambient temperature...

however, now we may have inherited some gas gauge anomalies as a trade off... as long as I understand what its doing.. it doesn't bother me.

 

With many of these comments, I have to wonder -- Did these people watch their old analog fuel gauges as close as they now watch the Prius's pips? Or was it just unlikely chance that all my pre-hybrids with analog gauges had similar quirks?

 

Oh there have been volumes of discussions about the old already.... I think all in all, the new is much improved and acts more like a guage should act.. if it momentarily bounces to the next level.. at least the level is relative and accurate whereas before, the first 1/3 tank of gas was totally not monitored as it simply showed "full".

 

From what I've read so far it seems like the 2010 model (without the bladder) is a serious improvement. I also have, however, the issue with driving until there's just one "bar" or "pip" left on the gas meter reading yet only being able to put in 9 gallons. I guess it's just a safety feature, and I'm glad to read that others are noticing similar patterns as well. Now I know that I can get it down to "flashing" and still have over 2 gallons, but I guess it's best to err on the safe side and just fill up whenever one thinks it necessary.

 

A big part of the reason a two gallon reserve seems excessive is the great mileage of the Prius. If you were driving a typical 18MPG car, 36 miles to empty after a low fuel light came on would seem reasonable.

 

On my previous (analog gauged) cars, I have always noticed some 'slop' and never really given it a second thought. Perhaps there is something psychologically more convincing when it is expressed in the terms of "pips." One thing I've noticed about every prior vehicle I've owned, and have not yet with the Prius, was that the gauge moved slowly in the first and last 1/4 tank, and rapidly in between. Perhaps it does in the Prius, and the only reason I don't notice is because it uses so little gas.

 

It's the difference between accuracy and precision. The digital fuel gauge gives the impression of precision, with all of the distinct pips, but its accuracy is no better than the old analog gauges.

Tom