Humdrum update time! Car was in to the garage on Friday to get the exhaust leak looked at and my whole happening-since-March fuel overflow issue looked into.
Exhaust leak is now fixed, $145 CAD later....cannot complain about that price at all! A failed gasket and bolts were really the culprit of the leak....the bolts had rusted away to nothing and the back section was starting to separate from the mid section of the exhaust. The gasket was damaged by the exhaust leak, so, a new gasket and new bolts there and the leak was fixed! As for the disintegrated exhaust hanger...that was due to rust too....did I mention I hate the amount of salt they use on the roads here every winter? :(
My mechanic managed to take what was left of the hanger and re-weld/fab up a new one in it’s place. Luckily he did tell me the exhaust, itself, seems to be in very good shape, so that should last for awhile yet! :)
BUT...the fuel overflow issue....the one that’s been going on since I had the tank replaced in March, he didn’t solve that. As a refresher, every time I fill the tank now since the gas tank was replaced in March, I’ll get the tank filled to the point it’s full and the pump will click off.....and then gas backflows out of the filler neck for about 5 seconds and down the side of my car and ‘glugs’ back down into the filler neck:
He took a look at things and didn’t see anything obviously loose or disconnected or wrong anywhere. He thinks the issue may be the Canister Close Valve, which is a little solenoid valve on the side of the EVAP canister (#6....pardon Hyundai’s own typo in their own Service Manual, lol):
It controls venting to atmosphere through the pipe/fuel air filter on the filler neck from the EVAP canister/tank....though I would think an issue with that valve would trigger a CEL and I’ve had no Check Engine Lights come on at all...?
He didn’t want to replace it yet as the part is over $100 CAD locally from Auto Supply shops or the dealer, which is a lot. He knew it’s available for cheaper online so suggested I order it cheaper (he’s a nice guy), which is what I think I’ll do....found it for around $45-50 CAD online. It’s actually ridiculously easy to get to if the car is on ramps (I have those!) or on a lift, so I may even try changing it myself.
Also....maybe I am misunderstanding, but if that valve were jammed open....that would mean the tank wouldn’t overflow as there would be a constant way for air to escape through the EVAP canister/vent tube, right? BUT, from some skimming of articles and info online, I THINK I understand that the valve is supposed to be CLOSED when the car is off so that the fuel in the tank doesn’t evaporate....? So if it was jammed closed...isn’t that the position it would NORMALLY be in when the car was shut off anyway...and if that’s the case, it wouldn’t affect my backflow issue...? Maybe I don’t quite understand how the system works...
The only other thing we can think of is that the canister, itself, might be clogged or the vent tube, itself...I used to have a tendency to ‘top off’ the tank just a bit after it clicked off (i.e. one of those ‘the fill-up stopped at $17.75...I’ll top it off to a round $18.00' type things). Yes, I know that this is supposedly bad, and I no longer do it (when the pump clicks off, I stop), but I wonder if doing that has somehow saturated the EVAP canister and is causing my issue...but if THAT is the case....why did it only magically start after I got my car back from getting the tank replaced...and was perfectly fine before that, despite me filling my car that way for years...?
Anyone out there with a better understanding of how EVAP works that might have an idea what’s going on or tell me if I am misunderstanding how the CCV works?