Gas Gauge or Gas Tank Problem???

interesting. Possibe bladder vent valve not working properly or tank vent valve or canister vent valve not allowing the air to escape from the bladder so the pressure kicked the pump off. It'll be interesting to see how far you go on your "full" tank. If your going in for service tell the SA that you had a problem and see if the Prius tech can do a scan of the compute and see if any codes are pending and not set.

 

I had something similar happen just once. It was on my (one) long trip. The gas gauge was at half, but I had no idea where the next convenient gas station would be, so I decided to fill up. The car was warm from driving for a number of hours, and the weather was warm.

A small fraction of a gallon went in, and the pump clicked off. I tried again several times, and only a few hundredths of a gallon went in each time. I went inside and told the attendant I was going to pull over to another pump.

At the second pump, same story. But I found that if I held the pump handle VERY gently (nowhere near the first notch) it would pump. But then I was scared of overfilling. I guesstimated how much gas I had used and pumped a gallon less than that.

The tank was nearly enough full to procede, and I had no further problems. I wrote it off to touchy pumps, but suspected it might also have something to do with the unusual tank on the Prius.

It has never happened again since then, but I've never again tried to fill the tank with more than 3 bars showing. And because my driving is all around town I have only once or twice filled up with more than one bar showing.

 

I'm coming up on 8,000 miles, and I've decided to only fill up when I've driven off at least 10 gallons of gas at the current MPG average. 47.1MPG means no fewer than 471 miles before more gas.

Since I'm cramming all the gas I can into the tank, this has been working well and I haven't been blinked at by the gas gauge for several tanks now...

 

This phenomena has been explained elsewhere but I'm not able to locate it. I have the same experience whenever I fill up at a specific gas station. I'm brand loyal (Sunoco) and at this one station they have these fume suppression hoods on the gas nozzle and when I press it up against the opening for the tank the quick shutoff behavior occurs all the time. I go to other Sunoco stations that do not have that hood and I never have a problem. I don't believe it is a problem with the car, just the nature of the pump you are using in combination with the sensitivity of the auto shutoff.

 

I am bringing this thread up again because I had this problem on my very first fillup (two week old 04 Salsa #7). Waited until I got the flashing bar and stopped for gas. Mileage was 507.

Is there a "technique" for filling up the tank?

My apologies if I'm asking for help on a topic that has been addressed in detail elsewhere on this site. I'm still trying to find my way around and find what's where. :roll:

PEACE

 

This is common when the previous customer at your gas pump doesn't know how to correctly 'top-off'. With the vapor recovery systems in most gas stations, here's what happens:

The most common cause of blocked vapor lines is customers topping off their gas tank. When a gas tank overfills, gas travels back down the vapor hose and blocks the line. Unless the line is cleared, the next customer will have trouble keeping the nozzle from automatically shutting off while pumping gas. (Taken from http://www.husky.com/handbook.htm#Don't)

Of course, this also shows that when topping off with the nozzle completely in the filler neck, the liquid gas will travel down the Vapor Recovery lines, yet still charge it as gas going in your tank, hence producing incorrect readings on the meter.

My solution - when the pump clicks off, let it sit a bit. Clean your winshield, check your oil, keep yourself busy for a bit and let the gas settle. Then 'fill up' extremely slowly, with the VRS holes on the nozzle outside of the vaccuum in your tank line. Do this only with extreme caution, and only if you're interested in squeezing out every extra mile from your tank.

-m.

 

"the VRS holes on the nozzle outside of the vaccuum in your tank line"

I'll have to look at the nozzles here in MD, but I don't recall any holes on the nozzle at this particular station next time I go in.

"when the pump clicks off, let it sit a bit"

I had only put in maybe a tenth when it clicked off...

As EricS stated, "When I started to fill up, the nozzle immediately shut off, as if the gas tank were full." My particular story continues that in order to get the gas flowing, I pulled the nozzle almost completely out of the tank. Got about 8 gals in and then my baby regurgitated/spittled/ ukeleft: some significant amount of gas (wasn't just a few drops)

Once it settled down, I put the nozzle back in and tried to replace the gas that had exitted and whatever more I could get in since I didn't think 8 gals was enough. Couldn't get anymore in.

Went on my way. Gauge went to full and then lost a bar after two or three miles.

Again, it was my first time trying to put gas in the car (my dealer had it full when I picked it up )

Thanks rflagg for your response, but I'm not sure it helped me. I am a blonde at times though

 

Well, that definately sounds more like a car problem than a gas pump problem - from most reports on here (and on my car), the first bar almost never drops before 100+ miles have passed.

Oddly enough, one thing that the dealership did when I had my fuel gauge updated (they had a fix for the first run of 04s) was to "replace defective fuel filter neck" when I actually let them know to be careful of something else unrelated. Perhaps if you get the same type of response on your next fill up, you might want to talk to the dealer & see if they can find anything wrong.

This car is very fickle about getting a full gas tank, mainly because of the bladder - many people have reported that they can regularly only fill 7-8 gallons. However, your problem sounds more complex since your gauge dropped off so quickly. The one (slightly) downside to doing gasoline fillup tests with this car is that they don't come that often because it gets such good mileage. Keep us up to date on it!

-m.

 

What's the big deal about "topping off"? All you get by doing this is a tenth of a gallon or so. We're not flying the Atlantic non-stop, here, so it seems to me to be a waste of time to try to get absolutely as much gasoline as possible into the tank. When the pump shuts off, I hang it up and go on my way.
Bob

 

I have also had problems with the gas pump clicking off too early. We don't have gas pump VRS here in southeastern Michigan so it isn't the pump problem described earlier.

I went to fill up this morning (guage was down to two bars). The pump clicked at about 2 gal. I kept trying to get more in (adjusting position of the fuel nozzle in the tank to make sure that wasn't the problem) but gave up at about 2.4 gal. The guage now shows 6 bars and the mpg didn't reset.

Previous times this has happened were when the tank was 3/4 full and I was topping off before leaving on a trip. This is the first time it has happened on a near empty tank.

For background, it is an '04, with a VIN number above the range in the Fuel Guage TSB. And, if you are interested, we ordered it in November 2003 and took delivery at the end of August 2004 - a nine month gestation period for the newest member of the family.

 

I would have wholeheartedly agreed up until the not-too-distant past.

In my case, it was more like 3 gallons than a tenth. The first time the pump had clicked off, as I recall, at under 7 gallons. After "topping off", I discovered I had bought 9.6 gallons of gas! The next time was even worse; click-off at 6.5 and I was able to squeeze in over 3.5 more (total of 10.1).

Hence, I have now relinquished my membership in the "click-off" club............although I'm still probably considered a member of other clubs with similar-sounding names. :lol:

 

I normally fill the car until it shuts off automatically. I also do a mental estimate of how many gallons I expect to add, based on the computer MPG display and the number of miles on the tank. I usually plan to fill up at about 480 miles on the tank, and time it for a station near my house that is usually a few cents cheaper than others.

Once, I had the problem of the nozzel shutting off to soon (say 4 gallons) and I gave up after adding 8.281 gallons. My calculated MPG was 58.4! (My next tank, I added 9.41 gallons, but my MPG was 36.7, calclulated).

My car falls in the VIN range for the fuel tank TSB, but my average fill up has been 9.14 gallons, with usually 440 to 490 miles on the tank.

So, perhaps it is just a random tank that you had a problem. Best wait and see if the problem repeats itself.