Refueling with engine running? VAPOR CANISTER concerns
 

Greetings all,

I recently had a bad vapor canister that was causing all sorts of performance, idling, hunting, hard start, fuel vapor smells, etc problems.

They replaced it and oddly enough it corrected about 99% of all of them!

The dealer previously was throwing parts at the car MAF sensor, Oil separator, Crank sensor, Throttle body.... well ... it turned out to be the canister which was oversaturated.

Dealer said it was ruined because i had refueled the car while it was running. They said to NEVER do that because the fuel then flows directly into/thru the vapor canister thus saturating it. I'm not just talking about 'over' filling or 'topping off'... they said never refuel with engine running.

Aside from the safety hazards assoc with this... has anyone heard of this No-no?

thanks,

refueling with engine running is usually considered a total no-no safety-wise.

thanks for the reply... but as i said.. ASIDE from the safety aspect.. i'm inquiring about the car performance / technical aspect only...

no - never hears of it. I have refueled my car hundreds of times with it running.

What car do you have?

2007 c2-s

I refuel all my air cooled 911's while the engine is running. I'm always concerned they won't restart :-)

Oh never mind. Most of us drive the old air cooled stuff and probably does not apply. Need to go in the 997 forum or maybe rennlist?

I refuel my 2015 truck and 2006 Taurus running all the time. Never a problem.

I would raise hell about the other parts changing that went on with out proper diagnosis and get your money back :-)

You will throw a check engine light for sure EVAP SYSTEM FAULT

luckily ALL the other parts were covered and paid by my extended warranty company or yes.. i would have raised hell about it...

actually the only thing not covered ... was the vapor canister which i had to pay for.. but got a used one for 1/2 the price which they installed because they could not locate one... as they were out of development and no time frame from porsche as to when they would be available again ? WTF?

anyways.. its running better now which is all that counts.. but i sill have leary of the car HAVING to be turned when refueling or you risk damaging the canister??

I cant believe how many people here actually fuel a vehicle while running . In this country they will instantly kill the pump on you if they notice as you are not only endangering yourself, you are also endangering the other people around you . Hell why not light up a smoke too while chatting on your cell phone..

IMHO the shut car off while refueling thing is left over from a time when there was much more danger. Modern car designs have mostly mitigated the danger. I dont feel like doing the research to present the proof but I read this somewhere and it stuck. In order for a flammable atmosphere to be present you could not stand to be in the area. There is a flammable atmosphere inside the fuel fill tube down into the gas tank but the chances of a spark getting in there are on the order of getting hit by lightening.

I think there is much more dangerous situations at the gas station than a running car igniting the gas fill.

I think someone stealing your running car while you are filling it is 100x more dangerous and likely than an ignition event.

I respect others opinion but that is my belief - maybe myth busters will do a test.

It is more dangerous to get back in your car while you are waiting for it to fill then to leave it running. That is why women are way more likely to experience a refueling fire. They are much more likely to get back in the car while refueling. (Why is that?) The static electricity generated by sliding in and out of the seat increases the chance of a spark when you grab the nozzle.
(Of course this assumes your car isn't a hodgepodge of slapped together faults.)

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Basic fueling safety includes touching the car before touching/grabbing the nozzle when it is in the car. It doesn't hurt to do the same while you are holding the nozzle right before you insert it as that can allow any charge the car has to discharge through the grounded nozzle.

I really appreciate those of you who have hijacked my thread to preach on your own agenda.
I simply was inquiring about the effects on the vapor canister when refueling and specifically mentioned NOT on the safety aspects.

Might have gotten a better response had you posted in the correct forum to start with.

We air-cooled guys can be a bit crotchety, or so I'm told.

Here's my theory on why the mechanic may have given you that advice. It's only speculation, so take it for what it's worth. BTW, I'm not familiar with the vapor system on your particular year Porsche.

Part of the vapor system is connected to the filler pipe, and it is a closed system. Excess fuel when filling the tank flows through a tube into the recovery tank where it vaporizes and eventually the vapors are drawn into the canister. If the car is running, theoretically the excess fuel will fill the overflow tank because the vacuum caused by the running engine. Once filled, the raw fuel also will be drawn into the canister and may saturate it.

Personally, it seems a bit remote to me, but I do know that newer cars advise not to overfill the tank, with the engine off, for the same reason--raw fuel flowing into the vapor system and saturating the canister, triggering a warning light. Again, a lot depends on how the system is set up on your car and, possibly, filling with the engine running is comparable to over filling with the engine off.

Thank you!! perfect reply and i much appreciate it! That does make complete sense....what is odd in all of this... (even dealer states) is that code was never thrown with any of this.. thanks again!

This makes sense.

I don't fill my 03 Passat with engine running but I know my son, Crash, has. But I am guilty of historically over filling.

Anytime I put gas in I have to stand on the gas pedal to get enough air in to stumble start the car. Guessing way too much vapor in there.

I do have an EVAP code which says it is some frammitz valve which I have replaced twice now in the engine bay. Clears code long enough to get e-checked and then back on in a couple of months.

Good luck.

I pulled into a gas station last summer in my P car. Lady next to me was inside her car talking on her phone. I walk around the back of my car and start to hear a splashing sound. I look over and gas is spilling all over the place and she's still talking on the phone. I go back and get in my car start it up pull up and she is still talking on the phone and looks over at me . So I point to gas pump and she jumps out. I drive off with no gas. A week later I go back to the station and asked about her. He said she dumped six gallons on the ground that day. Major clean up for them.

It's too darn bad that GCB got his panties in a wad over some sage advice on refueling. You, buster, have been lucky while being unwise at the same time.

Yes the military does hot refueling of helicopters but there's a guy standing there with a fire extinguisher and the procedure is done under emergency conditions.

Geesh!

Tom

glad we got that military question answered?