EVAP system

[SzymekCRX]

Hi

I've been diagnosing the EVAP system for some time and I came up to some thoughts.

I have a question though - should this line in the picture that goes to the fuel tank should be air tight ? In other words should the tank capped with a filler cap is to be 100% sealed and the only way out should be through this red marked line ?

[SzymekCRX]

FYI: It does not have to be sealed tight.

Solved my EVAP problems and I finally heave EVAP OK

[hahnmgh63]

What was the fix. Sorry I couldn't check my lines for you but I'm half way around the world for the next month.

[Jimmy Joe]

Bon Voyage friend Hahn, and happy return !

[SzymekCRX]

Well, it's embarssing to say but it was the first suspected part - N80. I've tested it from all the sides using my fancy methods and tools and assumed that was not faulty.

[kday]

I replaced my N80 recently too, and noted that the date code on the part I removed was 2008. I hope whoever designed that part didn't design anything else on the car.

[hahnmgh63]

I mentioned before that our N80 valves look to be indentical to the ones on Porsche Cayennes and on the Cayenne forums they are known to be a fairly common failure. I have a spare one for my Cayenne ready to go just in case and may even do it for preventions. I mentioned before but I wish I knew if they were identical as the Porsche part is a bit cheaper than the Audi part.

[kismetcapitan]

what symptoms are you seeing when an N80 purge valve fails? I'm at the end of my rope; whenever the car decides to purge fumes into the intake, it ends up in the engine bay instead. Or rather, once in a blue moon, it decides to dump fumes in the wrong place.

[SzymekCRX]

First symptoms - CEL !

[SFJ_RS6]

Does it set any VAG-COM error codes in addition to lighting CEL? Just hoping for some more specifics...

[kday]

Anything that illuminates the CEL will set a code.

When my N80 was bad, I had this code:


16825 - EVAP Emission Control Sys: Incorrect Flow P0441 - 002 - Lower Limit Exceeded - MIL ON