Toyota Prius Forum banner

1 - 9 of 9 Posts

·
Premium Member
Joined
·
2,820 Posts
dracula said:
How do you suppose I manage to get 13 gallons of gas into my '04, given that it has a 11.9 gallon tank????
1. you don't have a north-american style of Prius, so you don't have a bladder in your tank (and therefore the tank holds more fuel)

2. you overfilled, filling the filler neck and your charcoal canister, poisoning the emissions systems.

3. you overfilled, and the excess fuel was taken back into the vapor return line on the gas station pump, to spill out onto the next person to use that pump. (you paid for the gas, but didn't actually put it into your car).

4. the gas pump you used is in desperate need of having your local weights & measures inspector check it out!
 

·
Registered
Joined
·
209 Posts
Michelle,

This is a confusing issue for me as well. I'm sure I have the American-style car with the gas tank bladder, for one thing. But I'm wondering a couple of things:

1. How elastic is this bladder? Does it vary with temperature?
2. If it is in fact elastic, how accurate is the 11.9 capacity figure?

This weekend we drove from NJ to VT and back, around 800 miles round trip. On the way there, we got about 46 mpg because of all the mountain climbing at 75 mph. My husband filled the tank in VT before we went home. I don't remember the exact figures at the time, but I estimated the car would take 7-8 gallons (it was somehting like 350 miles on the tank, about 46 mpg. So that's 7.6 gallons); he put in 9.5. None dripped out. On the way home we managed to get 47.0 mpg on 464 miles with one bar showing but not blinking. I have to say the first 6 bars disappeared MUCH more slowly than usual. So I figured this morning I would fill up with 9.9 gallons. Well, the car only took 8.3. Either I was getting 55 mpg (doubtful) or the car just took a lot more gas than usual at the previous fill-up. Or the mpg readout is faulty. Or, one of the other choices you mentioned above, most likely #3. So:

1. If we overfilled and "poisoned the emissions system," what real damage did we do? Permanent and needing repair?

2. If the bladder is elastic, how can we ever judge how much gas we have?

3. HOW DO WE FILL THE TANK PROPERLY??? :?

Thanks for any insight you can offer.

Susan
 

·
Registered
Joined
·
9 Posts
Discussion Starter #4
The temperature angle occurred to me, but I forgot to mention that this time of year in the desert it's around 110 degrees here... but to clarify, I am definately getting as much as 2 extra gallons of gas in the car, the readout confirms this. I, too, would be very unhappy if I'm damaging the car by topping it off like this. .... Sure wish my gas gauge told me how much gas I have
 

·
Premium Member
Joined
·
2,820 Posts
some articles for why you shouldn't be topping off your gas tank (just stop at the first click!):
http://www.patgosscarworld.com/donttop.htm
http://www.phillyburbs.com/pb-dyn/news/ ... 23947.html
http://enviro2.blr.com/display.cfm/id/48985
http://www.sbcapcd.org/edu/dont-top-off.htm
http://www.weights.az.gov/Shoppers/gasstations.htm

note that the Prius has been known to "belch" gasoline back at people who overfilled, particularly on a slow pump setting...

anyhow, yes, the bladder tank does change in elasticity based on outside air temperature. In the colder winter months you won't be able to fit as much fuel in as you would in the warmer summer months.
 

·
Registered
Joined
·
623 Posts
I never top off. But once (just once) a faulty pump failed to shut off and gas came belching back out. Maybe half a cup before I managed to jam the gas cap back on.

Is it likely I did any permanent damage to the vapor recovery cannister?
 

·
Registered
Joined
·
209 Posts
Thanks, Michelle. I'll stop topping off, too, and I'll clue in my husband. Now if I could only get the gas station attendant to do the same . . . (NJ only has full serve pumps)

Susan
 

·
Registered
Joined
·
110 Posts
I wasn't aware that non US Prii did not come equipped with the bladder tank. While the bladder makes it harder to get an accurate indication of how much gas you put in, it is FAR safer in accidents. Racing cars use them for this reason. The bladder expands to hold the gas put into it, but NO air pocket above that gasoline level, so there is no gas/air vapor to cause an explosion if the car is impacted. Why would they put a less safe alternative in non-US cars?? It would be cheaper just to put the same tank in all Prii regardless of where they are sent.

Eventually, the bladder will stretch to completely fill the metal box that surrounds and contains it, so your fill ups will become more predictable and consistent.

As for the discrepancy, two gallons is a lot of extra "spillage" and you would most certainly notice if it were collecting somewhere besides the gas tank. I can't believe that it's going back into the gas pump or overflowing into the catalytic converter; there should be no connection between the gas tank and the catalytic converter.
I vote for pump meter error at your gas station. Try filling up at various locations. If problem persists, see your dealer.
 
1 - 9 of 9 Posts
Top