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Discussion Starter #1
A few weeks ago I did a HPDE track weekend event at Michelin Road Atlanta Raceway. After the second day I left the track and stopped by a gas station to fill up. After filling my car up I noticed what looked to be water dripping out behind the rear passenger side wheel well. Upon further investigation, I found out it was gas! :surprise:

After sitting there for nearly an hour to let the gas evaporate while i desperately researched it, I found out that it was coming from the evaporator canister. Has anyone heard of this happening before? Could the high speed driving at the track have caused it to fill up the evap canister causing it to spill out when I filled the car up?

I have not had a problem again since that original incident. However, I work from home and havent driven the car much since then. This weekend I am going to take off the wheel well to see if I find anything wrong.
 

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You probably overfilled the fuel tank. Best procedure is to put the pump nozzle on automatic and when it clicks off, don't try to top off the tank. These tanks are designed to provide some air space for fuel expansion. When you top off the tank, you fill it completely and risk flooding the charcoal canister which can damage it.
 

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A few weeks ago I did a HPDE track weekend event at Michelin Road Atlanta Raceway. After the second day I left the track and stopped by a gas station to fill up. After filling my car up I noticed what looked to be water dripping out behind the rear passenger side wheel well. Upon further investigation, I found out it was gas! :surprise:

After sitting there for nearly an hour to let the gas evaporate while i desperately researched it, I found out that it was coming from the evaporator canister. Has anyone heard of this happening before? Could the high speed driving at the track have caused it to fill up the evap canister causing it to spill out when I filled the car up?

I have not had a problem again since that original incident. However, I work from home and havent driven the car much since then. This weekend I am going to take off the wheel well to see if I find anything wrong.

Not sure how the gasoline could have been coming from the canister. The fuel/vapor system is a sealed system once the cap is in place.


The only explanation if the gasoline was truly coming from the canister would be the canister has suffered a failure of some kind that lets liquid fuel leak out. But even this has a serious flaw. The canister is not intended to hold liquid gasoline, only vapor. Exposure to liquid gasoline can and will ruin the canister, its activated charcoal.


What probably happened you over filled the fuel tank and some how fuel got in one of the lines that normally should only contain vapor and kind of venting anomaly forced this fuel out of the vapor line. The vapor line connects to the fuel filler tube up near the top and this can have fuel leaking out and possibly dripping off the canister.


This might have been exacerbated by if you just left the track after a session and the fuel in the tank might have been quite hot. Not hot enough to boil (approx. 181F) but hot enough to be very actively vaporizing (which happens at a bit over 90F).


If there was a leak in the fuel/vapor system I would expect the CEL to be on. The car's engine controller tests for small and large leaks in the fuel vapor system.


If you repeat the scenario again you might consider only filling up the gas tank half way. This allows plenty of extra air space between the fuel and the top of the tank where there is a vent line. The fresh gasoline lowers the temperature of the fuel in the tank. Then at some point you can stop and fill up the tank the rest of the way.



Regardless be sure you avoid over filling the gas tank. If the tank is filled too full liquid fuel can get into the canister and this puts this canister at risk of being ruined.
 

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Not sure how the gasoline could have been coming from the canister. The fuel/vapor system is a sealed system once the cap is in place.
It's not as uncommon as you might think. Fuel slosh/movement could certainly be a factor here since the veh was on a track, and of course overfilling ('topping off') can introduce liquid fuel into the purge solenoid & vapor line.

OP - if your EVAP system is functioning normally now (no faults), I wouldn't worry about it too much but you may want to check the canister to make sure it isn't completely saturated w/liquid fuel. It is possible, depending on driving/operating conditions, that your PCM hasn't yet completed all of the active & passive decay tests necessary to set a CEL (related to EVAP).

Bottom line - aggressive driving and topping off can/will introduce liquid fuel into places it shouldn't be in the EVAP system.
 

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Discussion Starter #5
Thanks guys. As a note, I did not overfill the tank. Once the fuel nozzle clicks off then I call it a day. I never try to top off as its a bit silly to do. However, the nozzle could have been defective and maybe it didnt shut off in time?

I too was thinking the CEL should've come on if the system was compromised. Each of your theories makes sense. I appreciate the input.
 
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