Charcoal canister filter blocked?

[manc]

Just had a look under the bonnet with the engine idling on my Mk3 1.4 and noticed that the hose to the EVAP valve is being sucked flat for three inches, so I tried to manipulate the pipe round again but couldn't, but could feel the EVAP valve pulsing.

I don't know what kind of air flow to expect through this filter, could my filter be blocked?

[Crasher]

More likely that the valve is stuck open.

[manc]

Thanks for the speedy reply.

Oh dear! these valves aren't cheap, and if it's pulsing it's not an electrical but a mechanical fault, with the valve seats?

Would still like a figure for air flow through this filter, as sucking the hose flat doesn't seem like I'm getting a lot, unless a short pulse of vacuum is all that it's designed to handle.

[manc]

Some posts about charcoal filters here http://www.thesamba.com/vw/forum/viewtopic.php?t=421822

[manc]

Turned out it wasn't blocked. Oh well, another theory bites the dust.

[Crasher]

Replace the pipe from the injector body to the EVAP with VW hose N 900 801 05, you need 510-mm and it is sold in 1 meter units BUT the dealer has to order it in 5 meter rolls. At £14 a meter I hope they don’t try to make you have 5 meters. If this collapses the feed to the EVAP must be restricted.

[manc]

Hi crasher, thanks for the full spec on the vacuum pipe.

I actually pushed a smaller pipe into the one coming out of my charcoal canister in order to suck on it, and was able to suck petrol fumes in quite freely, not really recommended.

My EVAP valve has a small resistance before it opens when I blow or sucked through it. I just haven't had a multimeter on it yet but realize that idling the engine with the said pipe off will also tell me if it's working or not.

Edit, just tested it, my EVAP valve is also working OK.