Purge Valve

[S4_dan]

This purge valve sits near my air box and 'clicks' non stop! Is this the normal operation of this valve? Sometimes it's really fast and can hear it inside the cabin, other times I can only hear it when i'm under the bonnet with the engine running.

Part number: 085 133 459

But I can't seem to find any other online? Has this part number changed?

Cheers,

Dan

 

[Arrkon]

mine does the same. never had a problem. so would suggest its normal. yours may be getting worn if you can hear it in the cabin though...

 

[Jason.s]

Means its probably cracked and is leaking air. Mine did it but i originally plugged it and now disconnecting the piping to it and planning on binning the cannister in the wing. Its about £70 to replace

 

[aragorn]

i was thinking about removing mine on a drive to remove weight and simplify, however i remember back to my old nova, which didnt have one, and there was always a lingering smell of fuel vapour around the car.

The carbon canister is there to absorb all these fumes and allow the tank to breathe. If you remove the canister you need to leave the tank vent line open to ensure the tank can still breathe, and as a result you get vapours wafting out.

I'd be interested if it works without any smells though, I'll be glad to remove 700feet of pipework from under the bonnet.

I had actaully considered leaving the canister in place, but removing the connection that runs to the engine. That way the tank can still breathe thru the filter, and the filter absorbs the smells. I can simplify the engine bay pipework.

Thaughts?

 

[Jason.s]

Well i removed that Y peice that branches between the TIP and the purge valve/cannister and just used a single hose to link it to the TIP. The purge valve is still plugged in but hangs down under the airfilter now and the rest of the stuff running to the cannister is tucked under the top lip of the wing. I`ve got a decat anyway so get the fumey smell in traffic anyway lol.

Havent fully followed where that hose goes properly. Just round to the inlet somewhere i think. Now its not feeding the cannister and only the TIP im wondering if i can remove it now and blank the TIP. Looked a few simplification threads on Audizine and some report error codes popping up but whether thats because they completely removed the purge valve or theres something else plugged in under the inlet? I saw some pics and theres a few of the one way valves but nothing with an electronic plug on..

 

[aragorn]

Having had a quick look, you've got the feed from the evap can coming in from the drivers wing, thru the valve, then out into the Y piece.
The Y piece has check valves set up in such a way that when the engines under vacuum, the fumes are drawn along the line along the bulkhead and into the inlet, and when its under boost its fed to the tip instead.

Presumably this is because at low loads, the TIP isnt under much vacuum, so you want the vac from the inlet. When on boost you dont want to blow the boost back thru the EVAP system into the fuel tank, so instead it diverts it to the TIP.

If you've simply connected the inlet side of the pipe to the TIP side, then the whole thing is redundant and can be removed and blanked off. I presume then this means your simply venting the line from the canister to atmo??

Any pics to ensure i've got it right in my head?

 

[Jason.s]

I know its for a B6 but gives a decent idea of whats what.

Looking at it the pipe im talking about it does seem i could just eliminate it. Job for the weekend it seems. Bin the cannister and get rid of that hose completely and block off the inlet and the TIP

 

[Jason.s]

Goes just under the under pretty much where the TB is fitted so looking at it i`ll just leave a bit of pipe and clamp a bolt in the pipe to block it and do the same on the other end of the pipe where it goes into the TIP or stick a bolt in the TIP and clamp that if i can get down there.

How easy is it to remove the wing? Or would it be easier just to take out the arch lining and do it that way?

 

[aragorn]

Take the arch liner out and you can get at it.

I'm still not sure its a great idea, as you've then effectively got an open pipe to your fuel tank dangling around under the car...

But i sure would love to get rid of all that cruft. Maybe i should disconnect the evap line from the wing and leave it open and see if there are any obvious fuelly smells... If there are none then go ahead and remove everything else.

 

[Jason.s]

Ah good i`ll do that. Far less hassle than taking the wing out which i`d probably mess up some how lol.

Yeah i`d probably block it off tbh. Wouldnt want an open pipe going into it and getting all sorts of crap inside it. Will see what the story is once i remove the cannister and i`ve got a clearer idear what im being left with.

 

[aragorn]

Cant block it off, surely if you did that the fuel tank would collapse in on itself as the level drops and/or explode when the fuel heats up and expands...

The vent really needs to stay open.

 

[Jason.s]

Ah i see. Didnt think about that.. Theres a lot of cars out there that dont have evap cannister so i guess they use some other sort of vent. I`ll have to see where about the piping sits and try and put it out of harms way best i can.

 

[aragorn]

Back when i had the nova, the carb models had the vent line wrap around the tank and then end in the rear wheel arch. It had some inline valve to ensure no actual fuel could come out but air could pass in and out.

On EFI models the same line was extended forward into the charcoal can then into the engine via a solenoid in the same manner as the A4.