Damage to evaporative emissions system?

Hi all -

Sorry if this has been covered elsewhere, but I couldn't find anything that quite answered my question upon searching.

The scenario: I recently filled up at a station that, according to the attendant, had just lost electrical power but power had been restored. The pump was flowing agonizingly slowly, so I asked the attendant what was up, and he said the system needed 20 minutes or so to reboot before the pumps would flow at the normal rate--sounds kind of specious to me, but I was in no hurry, so I figured so what, I'd wait it out.

Well, eventually the tank filled up, and then some. The pump's auto-shutoff failed to work (my guess is that the flow rate was so slow that the back pressure failed to build up to the point to trigger it, but, whatever...). Gas was dribbling everywhere by the time I noticed it (since it was taking so long, I wasn't paying close attention).

I don't think a lot of gas was spilled, but, I'm guessing the tank, filler neck, and charcoal evaporative-emissions canister got as full as full can be. I mentioned this to the attendant, and he dismissed my concern of any damage by saying that any damage could only happen if the engine had been running.

(Further info--the car ran well over 200 mi before the first 'pip' dropped off the screen, giving an idea of how 'full' it was. Also, the calculated mpg was 46.3 (worst ever) compared to 56.8 for the admittedly somewhat, but not that much, optimisitic MFD).

So, two questions:

1. - (just out of curiousity) - Is the idea that the evaporative emissions system can only be damaged by overfilling the tank when the engine is running the load of horsesh*t that it sounds to be?

2. - (more important) - How likely is this single event--I always stop when the auto-shutoff kicks in--to damage the evap. system on my car?

Thanks much,
Tim

 

Thanks for the reply. Regarding #1, whether BS or HS, I knew I smelled S...

Regarding #2, unfortunately, I gassed up at the end of the day and probably only drove a few miles before parking it overnight (dang the luck). I did do a fair bit of driving the next couple of days, so hopefully that might help. My fear is that I won't know for sure until I get a VEIP test, and by then my chances of demonstrating any damage will be zero.

~T

 

Thanks, all, for your info and reassurances. Normally I do keep a close eye(usually hand as well) on the nozzle while it's filling, but this was soooo slooowwww I think I would have frozen in place. So I whiled away the time bantering with the other customers about how strange the whole thing was. Lesson learned, I guess.

p.s. - Tom, thanks for your insight--didn't know that about the Prius (then again, books are filled with what I don't know...).
Cheers
~T

 

I agree with your gist, but, just to clarify a couple of things:

(1), Yes, in most states in the US there are little 'latches' built in to the trigger to allow you to leave it in place. The pumps have an automatic shut-off, which is supposed to stop the pump when the tank is full, as the pump measures by back pressure. Some states do not allow this--Massachussetts is one, I believe, and if I may infer from Tom's post above, Michigan may be as well. The auto-shutoff kicks in if you are holding it, too, by the way; if it were a matter of squatting down and looking in to listen or look to determine how full it was, I suspect more gasoline would be spilled than otherwise.

(2) - As I indicated in my post, there had been a power outage, which (allegedly, as per the attendant, whose credibility is admittedly not much on this end) resulted in the pumps going slowly--and I do mean it was agonizing--it took a good 15-20 minutes to fill up (it would slow down even more when someone was using another pump at the station). So, it wasn't exactly "two minutes" we're talking about in this particular case--and this was buying just over 9 US gallons; imagine how long it would have taken with a larger vehicle or tank.

But, your overall point is correct. Perhasps incongruously as evidenced by the fact that The Powers Who Wish To Avoid A Locally Undesirable Fireball have, in the US anyway (and I'd guess many other places), installed these automatic shutoff mechanisms (regardless of whether they have the little 'latch' mechanisms that enable the aforementioned laziness...). When they work--which in my experience has been in every case I can remember, with this one exception--they are arguably more precise than most people would be by observing and reacting manually. Probably more important, it lessens the likelihood that some numb-nut wedges the gas cap into the pump trigger to hold it in place while (s)he runs to the bathroom/makes a phone call/stands there harvesting navel lint while contemplating the meaning of life. (I have seen this, though I doubt the contemplation was quite that cerebral.)


Cheers,
Tim

 

Thanks for the laugh. More accurately the sign should probably say "Person filling must stay within range of filth-covered camera 'monitored' by bored, underpaid, nihilistic former English major."

(but maybe, just maybe, the nozzle has eyes on the back of its neck? Someone called 1-800-492-TIPS? Just a thought...)

~T

btw no disrespect intended to English majors or others in any of the Humanities, the contributions of whom are woefully underappreciated, IMO...