As Duane points out, that's not quite right.
From??-- ?the round canister (part #12) is the air filter for diagnostic pump.
Here's my understanding of how it works:
Part 9 (the big rectangular part) is the vapor canister.
Part 15 is the Leak Detection Pump (LDP)
It has two functions:?
1. as the vent valve
2. as a vacuum operated pressure pump to check for leaks.?
In normal operation, the LDP is in mode 1, and the vent is open to the atmosphere:
Air can flow into tube 18, through the filter (12), into the LDP (15), through the vent tube (14), into the charcoal canister (9). As air flows in, the stored gasoline vapors come out of the charcoal pellets, and the air+gasoline fume mix is sucked back into the engine via hose 22, through the N80 valve (24) via the hose (25) to the throttle body to be burned off.
The fact that you have liquid gasoline and fumes escaping from part #12 and can hear boiling is consistent with the whole system being overly hot and pressurized.
Since Part #12 is just an air filter and is connected via tube 18 to the grommet #3 (listed as "clipped into the left long member") I do wonder if your #12 is actually clogged. ?That could explain why pressure is escaping there (rather than via tube 18) and also could explain why your pressure is building up in the first place: ? With the N80 open, vapor should be getting pulled out, but to do that part #12 needs to be free-flowing. ?If part 12 is clogged, even with the N80 valve open 100% fumes would be building up in the canister.
Part #12 is interesting. ?This diagram is for a 2001 and later - the 1997-2000 models don't have a filter on the LDP inlet at all. ?
I'm not sure why you need a filter there in the first place? Perhaps it serves to keep dust and grit out of the LDP? ??
If you can't find a new #12, I bet you could bypass #12 temporarily and see if that fixes your gas fume issue.
Mike
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On Jan 18, 2024, at 7:18 AM, Goffredo via groups.io <phi-lawn-0t@...> wrote:
On Thu, Sep 14, 2023 at 05:19 AM, Duane wrote:
On Thu, Sep 14, 2023 at 12:31 AM, Goffredo wrote:
mysterious round black plastic canister
I believe that's the air filter, p/n 7D0201849C.? I didn't find one online, but didn't look too hard.? The only reason for gas in it would be overflow from the tank.
I wanted to post a follow-up in case anyone comes sniffing around here with the same symptoms. ?A few posts back (
here?and
here with pic) the mysterious round black plastic canister which was spitting gas and fumes in my 2002 EuroVan appears to be the active charcoal evap canister. ?The part number that Duane identifies above is correct and, similar to older EuroVans, is no longer available new.
Please note that this is definitely
not a fuel filter, and it's definitely
not an air filter. ?It is specifically an active charcoal evap canister - just the new form factor as part of the 2001-2003 model year redesign. ?It would seem that, even though VW re-designed the Evap system for these 2001-2003 model years, they (at least, my) evap canister still suffers from the same problem as the previous design, where liquid gas collects in it during a particular sequence of events (hot temperatures, a recent fill-up, and a huge mountainous ascent). ?
And when such a sequence of events happens, it is most certainly a fire hazard. ?When we pulled over at 9200 feet, it was burbling and hissing and spitting liquid and vapor gas fumes mere inches away from some extremely hot engine components -- certainly hot enough to ignite fuel vapor on contact.
My take-away is to be cognizant of this problem, and on big climbs and in very hot temperatures, periodically check on it (or just give a listen for weird boiling sounds) and plan to give it a few hours to cool off. ?This canister does appear to have a weep hole in the bottom that would allow gravity to extract any liquid gas and so I can only assume it is self-correcting. ?Part of me wants to cut it open and make sure the charcoal hasn't turned to dust, but the other part of me doesn't really feel like dealing with it!
