Fillup Question

Fuel pumps click off at different times... I have had pumps at the same station click off at different points. Sometimes even the same pump nozzle will click off incorrectly. The only way to know 100% is to fill it to the brim. This may be good or bad, but not my current argument.

 

Another gain would be more accurate fuel readings... I know I personally don't like seeing that my fuelly and my car are in dispute... but then again, the car maker went through all that trouble to design something... they couldn't possibly be infallible... how'd that gas pedal fiasco turn out?

I'm just saying that I haven't heard of a single case of errors on the Prius, not that it hasn't happened. I'm not doing it and I'm not saying anyone should do it. But there has to have been someone who has pumped to the top on most pumps, sometime throughout the last 10+ years of Prii existence. That, logically, leads us to conclude that either a) Toyota is being over-cautious (which we all know they do), or b) this isn't as big a deal as it seems.

I can find plenty of arguments online for why you should change your oil every 3k miles and why you should let your car warm up, too. Doesn't mean anything to me. I base knowledge off experience 1st, then go to texts if I can't find anybody with an experience. So far, it's worked out for me.

So in conclusion... you keep not pumping to full, I'll keep not pumping to full. Other people will keep pumping to full.

 

IMO any advantage gained in following this protocol is not worth the possible risk to a new vehicle. Of course, I live in Oregon which disallows you from pumping your own gas, so it's not even an option to me.

Basically, unless I'm absolutely cornered...if the owners manual say's "don't do this"....I don't do it.

 

Our definitions of full tank is clearly not the same here. Did you take a look at how and the fuel evap system works? Or should I say understand them? I guess "doesn't mean anything to me" explains it.. so I digress..

 

I understand fully and know that the amount of miles I drive, the gas won't be lingering long enough to cause an issue...

 

Not sure how our definitions of full tank are different though... I don't top to slap full and neither do you, per your own admission.

 

I have 4 cars and I always top off to get the MPG and never had a problem.

 

I consider it full when it clicks the first time.. then I use the gallons noted on pump to calculate MPG. I don't fill it up to gas cap.

Perhaps we're bother answering different things on here but I was replying to you're question "Has this been confirmed or is it an urban legend? I see no posts anywhere on Priuschat about people having to replace their evap system."

Either way.. no worries..

 

I go to the click and then to the next dollar. This never fills the neck and I wouldn't want to anyhow. I am too OCD for anything except those 00's.

 

aaa.. I see.. I interpreted you were also filling it up to the cap as noted by OP..

 

So far as I know, the only damage when your evaporative canister goes bad is to the environment. Unless someone is testing for that, I am not clear how any of these people know they have not ruined it. (or, to be fair, that they have)

 

As previously mentioned... it should throw a Evap code and you won't pass emissions.

 

Topping up is not necessary to accurately calculate gas mileage. If you're fill up level varies a bit between fills: two, or three at the most fillups and all variation cancels out.

It is a good way to piss off whoever's waiting next in line behind you at the station, spill gas, possibly screw up evap. control system, and so on.

Spilling gas is a good way to mess up your calculation, LOL.

 

It's a 9 gallon tank. Even topping off with the nozzle as 1/2 speed I'm still faster than the majority of cars in the line...

 

and again... how messy is everyone that they pump so fast to get gas everywhere...

 

PriusCinBlack's point was that the tank average will be slightly different for every station/pump/weather condition/etc., but in the long run, the errors will average out (one will overfill by a lot, the next two will slightly underfill, etc.). If it didn't average out in the long run, you'd end up with en empty tank. Averaged over a few fill-ups, the discrepancy between calculated and what the car reports is the average amount off the car's estimate is.

 

Correct, but topping off until you see the gas will give you exact, every time.

 

YOU SHOULDN'T DO IT WITH EITHER CAR. FILLING TO THE GAS CAP WILL INTRODUCE GASOLINE INTO THE VAPOR TRAP MEANT TO TRAP VAPORS FROM THE GAS TANK AND DEFEAT ITS PURPOSE.
The emissions control depends on trapping vapors evaporating from the gas tank while the car is unused and then letting the gas tank as it empties draw the vapors in. By filling the vapor trap you not not only were in violation of emission laws, you were costing yourself extra $.
PS your owner's manuals should tell you that. And regardless of your refill technique its difficult to get the precise fill limit. The best way is to fill to the automatic utoff for several refills and average the mpg results. Or you could just read the displayed results and after auto cutoff, fill to the next whole dollar to keep the math simple.

 

Have you ever known anybody that ACTUALLY had issues due to this? I haven't, I did it on my Saturn for almost 200k miles and never had an issue. I know what it says in the book and I don't do this in the PC (too much work for a modicum of accuracy), but was curious if you ACTUALLY knew some one and didn't just go off stories.

Filling to the "shutoff" isn't in the least accurate. 2 different pumps from the same gas station will be different depending on length of time between services. The only "real" way to be accurate is to fill it to the brim every time. I'm not condoning this, nor am I saying you shouldn't do it. I'm just saying it's the only accurate way.