Warmer Weather = Less Gas in Tank??!

[bbianchi]

So I totally understand the concept of the bladder expanding over time as well as being more apt to expand in warmer weather. Well the past three fillups now have been on 80+ degree weather. However even if the last bar is flashing I honestly have to fight to get anything over 9 gallons in the tank. What gives?! This winter in the 40-50s I was able to sometimes get as high as 11. I can only assume that the light will flash at approx. the same time.

All three fill-ups were at different stations. I know for sure two were Emco Wheaton pumps (which are very popular, but very Prius un-friendly). It seems the Husky pumps are the best for the prius, but they are only seeming to dominate the Diesel side. The third pump was I want to say Goodyear but I could be wrong.

These Emco Wheaton pumps are just cheap IMHO. If you ever look at the nozzle they are constantly beat up, bent and very abused. Guess the cheapness is a why there are so many.

This winter I was able to get 500 miles per tank now 400 - 425 is about my max. My weekly commute for work alone is 325 miles and that doesnt count driving to lunch or any after work activities, OR the weekends. I was getting quite used to only filling up once every 7-9 days.

Is anyone else having a similiar issue recently?

[Frank Hudon]

no just the opposite. I've been able to get it full and get more miles to the tank. You might try and pull the nozzle out of the filler neck and then re-insert it and add more. Or you might have a problem with the canister or one of the vent valves. Another consideration is most pumps are calibrated for a set temperature and flow corrected to it. But if the car is hot and the bladder is too it should take almost the listed amount of fuel. Another thing to check is
1) air filter
2) tire pressure
3) take all the junk out of the trunk
a 2 MPG drop over 425 miles is a lot of fuel.

[hdrygas]

I guess that would be my experience larger tanks in warm weather smaller in cold. I would imagine the gas temp remains a near constant being underground. Some one in New Orleans needs to leap in here I noticed the gas tanks there were above ground in many cases. Warm gas? You can use this to your advantage. If you are feeling down because it is a cold gloomy day and you have had a string of warm days it is now time to fill up and calculate your MPG. I find that it is often a few tenths to a gallon lower that what I can do on a warm or hot day. Your calculated MPG goes up and you have a warm glow. Life is not so bad, even if in your heart you know that you will pay on the next tank when you go less miles and fill up with a gallon more gas.

[bbianchi]

<div class='quotetop'>QUOTE(Frank Hudon @ May 10 2006, 03:38 PM) [snapback]253138[/snapback]</div>

1) air filter
2) tire pressure
3) take all the junk out of the trunk
a 2 MPG drop over 425 miles is a lot of fuel.
[/b]

1) Air Filter has 10k miles (New Car)
2) Tires 40/38
3) No junk in the trunk, except maybe 2 pounds for the jumper cables, and 4 for the chains.

[Frank Hudon]

I changed my air filter at 11,500 miles as it was filthy. I drive on paved roads and it rains a lot to help keep the dust down. Pull it and turn it over and look at the side that sees the outside. You might just be surprised.

[hdrygas]

<div class='quotetop'>QUOTE(Frank Hudon @ May 11 2006, 06:21 PM) [snapback]253838[/snapback]</div>

I changed my air filter at 11,500 miles as it was filthy. I drive on paved roads and it rains a lot to help keep the dust down. Pull it and turn it over and look at the side that sees the outside. You might just be surprised.
[/b]

Changing filters oil etc is a cheep way to improve performance. Don't even get me started on the cabin air filter and allergies.

[DeadPhish]

<div class='quotetop'>QUOTE(bbianchi @ May 10 2006, 06:01 PM) [snapback]253111[/snapback]</div>

So I totally understand the concept of the bladder expanding over time as well as being more apt to expand in warmer weather. Well the past three fillups now have been on 80+ degree weather. However even if the last bar is flashing I honestly have to fight to get anything over 9 gallons in the tank. What gives?! This winter in the 40-50s I was able to sometimes get as high as 11. I can only assume that the light will flash at approx. the same time.

All three fill-ups were at different stations. I know for sure two were Emco Wheaton pumps (which are very popular, but very Prius un-friendly). It seems the Husky pumps are the best for the prius, but they are only seeming to dominate the Diesel side. The third pump was I want to say Goodyear but I could be wrong.

These Emco Wheaton pumps are just cheap IMHO. If you ever look at the nozzle they are constantly beat up, bent and very abused. Guess the cheapness is a why there are so many.

This winter I was able to get 500 miles per tank now 400 - 425 is about my max. My weekly commute for work alone is 325 miles and that doesnt count driving to lunch or any after work activities, OR the weekends. I was getting quite used to only filling up once every 7-9 days.

Is anyone else having a similiar issue recently?
[/b]

I didn't have a rationale like the Emco Wheaton pumps but I have noticed a significant difference between fillups at different stations. Background: I drive about 145 mi every day and have been getting right at 500 mi/Tank ( 490 in colder weather and 515 in warmer weather ) with fillups right around 10 gal +/- 2%. I almost always drive until the fuel notice and then find the nearest station.

I often fill up at the same station but often have to use another. I've noticed that the 'usual' place will allow me to put in 9.8-10.2 gal but if the alternate ones can vary from 9.5 to 10.6.

Extreme example:
Sat night after driving for about 25 miles with the warning blinking I pulled into a Texaco and expected to put in about 10.2 +/- based on driving 520 mi. It shut off at 7.2 gal and wouldn't let me fill any further. Stupid machine. I know it's only 3/4 full so I decide to wait and find another station. I get in and the bars go all the way up to FULL!!! Stupid Prius, don't you know it's only 3/4 full.

I'm ready for the next step which is... FULL is not really FULL. After driving for about 20 mi the top bar disappears ( normally on a truly full tank this takes nearly 150 mi ), 20 mi later the next bar disappears, 20 mi later another bar, until shortly I am right where I know I should be at about 3/4 full.

These machines really do need us humans to oversee their mistakes. Asimov was not wrong

[bbianchi]

I have noticed this exact same fuel gauge behavior myself with my fill up problems as well.