Erratic/Inaccurate Fuel Gage

tcpike · 10-09-2007, 01:42 PM

Since purchasing my 2007 Prius, I've had some concerns that the fuel gage doesn't accurately reflect how much fuel is being consumed or how much fuel is in the tank.

On a recent trip of 158 miles, the fuel gage dropped 4 squares or 1 square per c. 39 miles traveled. I had driven 100 miles and used 2 squares before starting this trip. The car's consumption screen was registering 47 mpg. Before returning from my trip, I filled the tank with 6.7 gallons. The consumption screen registered total miles of 258 since my last fill-up. The average based on the math (miles divided by gallons) is 38 mpg. Quite a discrepancy!

On my return trip, I traveled the 158 miles and the gage showed "full tank" (all 10 squares) the whole trip! The consumption screen was showing 58-60 mpg. In fact, I'm still driving on that tank of gas (now showing I've driven 179 miles and just today it dropped one square.

Has any other Prius owner noticed any odd, erratic occurances with their gas gage? (I've got an appointment to take the car into the Prius service person in two days to check this out.) Any comments would be greatly appreciated!

Proco · 10-09-2007, 01:48 PM

Do a search for "guess gauge" and all your questions will eventually be answered.

tcpike · 10-09-2007, 02:21 PM

Thanks for pointing out the thread to me, Proco. So, after reading through that thread, I now understand that the fuel bladder can cause the discrepancy in miles per gallon.

I guess I'm still not sure if this is also the reason for a full tank staying "full" even though I drove 179 miles. One of the responders mentioned sticking the nozzle back into the tank a few moments before closing the gas cap. Do you suppose I can save myself a trip to the mechanics by something so basic? Or is the "stuck full gas tank" another issue?

qbee42 · 10-09-2007, 02:34 PM

<div class='quotetop'>QUOTE(tcpike @ Oct 9 2007, 02:21 PM) [snapback]523201[/snapback]</div>

Quote:

Thanks for pointing out the thread to me, Proco. So, after reading through that thread, I now understand that the fuel bladder can cause the discrepancy in miles per gallon.

I guess I'm still not sure if this is also the reason for a full tank staying "full" even though I drove 179 miles. One of the responders mentioned sticking the nozzle back into the tank a few moments before closing the gas cap. Do you suppose I can save myself a trip to the mechanics by something so basic? Or is the "stuck full gas tank" another issue?
[/b]

Like many modern cars, the fuel gauge on the Prius stays at full for a longer than expect number of miles, then starts to drop. I assume the thinking is that a full tank is not a concern, but a low tank better register with some accuracy. Almost all gas gauges cheat on the full side.

Tom

tcpike · 10-09-2007, 03:01 PM

Tom, I can understand that to a certain extent. But, to drive 179 miles and still have the tank showing completely full? That seems a little excessive, don't you? I mean, it should've dropped about 4 squares (at least it did on the first half of my trip). Do you recall reading anyone else having this happen? Otherwise, it seems like something peculiar to my car and would like to have a tech look at it.

Proco · 10-09-2007, 03:24 PM

<div class='quotetop'>QUOTE(tcpike @ Oct 9 2007, 03:01 PM) [snapback]523224[/snapback]</div>

Quote:

Tom, I can understand that to a certain extent. But, to drive 179 miles and still have the tank showing completely full? That seems a little excessive, don't you? I mean, it should've dropped about 4 squares (at least it did on the first half of my trip). Do you recall reading anyone else having this happen? Otherwise, it seems like something peculiar to my car and would like to have a tech look at it.[/b]

This really is fairly normal for the Prius. In the summer I usually get between 125 & 150 miles to the first pip. In the winter, I get less. I would imagine this is a function of how much you fill your tank. I live in NJ and am not allowed to fill the tank myself, so I'm usually filled to the first click or the nearest $0.25 after.

FWIW, mine gets a little funky on the back end, too. I usually get around 90 on either the third last or second last pip.

The more you drive the car, the more you'll get used to it and be able to adjust your driving to what the gauge tells you. For example, I've learned that if I have 3 pips left, I can definitely make it work & back (~100 miles) the next day.

qbee42 · 10-09-2007, 03:51 PM

<div class='quotetop'>QUOTE(tcpike @ Oct 9 2007, 03:01 PM) [snapback]523224[/snapback]</div>

Quote:

Tom, I can understand that to a certain extent. But, to drive 179 miles and still have the tank showing completely full? That seems a little excessive, don't you? I mean, it should've dropped about 4 squares (at least it did on the first half of my trip). Do you recall reading anyone else having this happen? Otherwise, it seems like something peculiar to my car and would like to have a tech look at it.
[/b]

I can't recall anyone not having this happen in their Prius. It's completely normal. Remember, 179 miles is only about three gallons of gas. You have to get used to the mileage in a Prius.

Tom

tcpike · 10-09-2007, 04:35 PM

Thanks to everyone who weighed in on my question/cibcerb. I've also looked through some more threads and have decided that I'm going to cancel my service appointment. This is just another fun learning experience. And, thank god priuschat is here to help all of us newbies!

<div class='quotetop'>QUOTE(tcpike @ Oct 9 2007, 03:32 PM) [snapback]523270[/snapback]</div>

Quote:

Thanks to everyone who weighed in on my question/cibcerb. I've also looked through some more threads and have decided that I'm going to cancel my service appointment. This is just another fun learning experience. And, thank god priuschat is here to help all of us newbies!

[/b]

And, that mangled word at the end of my first sentence would be "concern"

Fingers of the wrong keys...

abq sfr · 10-09-2007, 06:32 PM

The guess gauge is inaccurate on both ends. Yesterday I had a blinking pip for 10 miles, drove to Costco and filled it up with 8.5 gallons after clicking the nozzle three times. Unless I have an incredible shrinking fuel bladder the guess gauge is exactly that. I should have been able to go another 150 miles on the last blinking pip.

richard schumacher · 10-09-2007, 11:02 PM

<div class='quotetop'>QUOTE(abq sfr @ Oct 9 2007, 05:32 PM) [snapback]523327[/snapback]</div>

Quote:

I should have been able to go another 150 miles on the last blinking pip.
[/b]

Don't try it; you probably won't get that far.

10-09-2007, 01:42 PM	#1
tcpike Join Date: Jan 2007 Posts: 7 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Since purchasing my 2007 Prius, I've had some concerns that the fuel gage doesn't accurately reflect how much fuel is being consumed or how much fuel is in the tank. On a recent trip of 158 miles, the fuel gage dropped 4 squares or 1 square per c. 39 miles traveled. I had driven 100 miles and used 2 squares before starting this trip. The car's consumption screen was registering 47 mpg. Before returning from my trip, I filled the tank with 6.7 gallons. The consumption screen registered total miles of 258 since my last fill-up. The average based on the math (miles divided by gallons) is 38 mpg. Quite a discrepancy! On my return trip, I traveled the 158 miles and the gage showed "full tank" (all 10 squares) the whole trip! The consumption screen was showing 58-60 mpg. In fact, I'm still driving on that tank of gas (now showing I've driven 179 miles and just today it dropped one square. Has any other Prius owner noticed any odd, erratic occurances with their gas gage? (I've got an appointment to take the car into the Prius service person in two days to check this out.) Any comments would be greatly appreciated! __________________ 2007 Prius, Pkg. 2 Purchased January 27, 2007 And, because of its color, Metallic Gray, have christened the car "Spalding"

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10-09-2007, 01:48 PM	#2
Proco Senior Member Join Date: Jun 2006 Location: The Beautiful NJ Shore Posts: 2,421 My Car: 2006 Prius Model: Package: #5 Thanks: 63 Thanked 97 Times in 56 Posts Friends: 9	Do a search for "guess gauge" and all your questions will eventually be answered.

10-09-2007, 02:21 PM	#3
tcpike Join Date: Jan 2007 Posts: 7 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Thanks for pointing out the thread to me, Proco. So, after reading through that thread, I now understand that the fuel bladder can cause the discrepancy in miles per gallon. I guess I'm still not sure if this is also the reason for a full tank staying "full" even though I drove 179 miles. One of the responders mentioned sticking the nozzle back into the tank a few moments before closing the gas cap. Do you suppose I can save myself a trip to the mechanics by something so basic? Or is the "stuck full gas tank" another issue?

10-09-2007, 03:01 PM	#5
tcpike Join Date: Jan 2007 Posts: 7 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Tom, I can understand that to a certain extent. But, to drive 179 miles and still have the tank showing completely full? That seems a little excessive, don't you? I mean, it should've dropped about 4 squares (at least it did on the first half of my trip). Do you recall reading anyone else having this happen? Otherwise, it seems like something peculiar to my car and would like to have a tech look at it.

10-09-2007, 06:32 PM	#9
abq sfr Senior Member Join Date: Mar 2007 Location: Albuquerque, NM Posts: 673 My Car: 2007 Prius Model: Package: #2 Thanks: 1 Thanked 0 Times in 0 Posts Friends: 1	The guess gauge is inaccurate on both ends. Yesterday I had a blinking pip for 10 miles, drove to Costco and filled it up with 8.5 gallons after clicking the nozzle three times. Unless I have an incredible shrinking fuel bladder the guess gauge is exactly that. I should have been able to go another 150 miles on the last blinking pip.