noisy charcoal cannister valve??

[s2martyn]

the valve is very noisey,,clicking on and off whenever i am on over-run..when the accelerater is pressed the noise stops.is this normal..i have had vagcom on and there are no faults...also as the aby engine is in the urq,i have not fitted the charcoal cannister so the pipe is venting to atmosphere

[mcandmar]

At steady idle the valve should pulse on/off as its venting from the carbon canister, sounds normal to me.

[S2central.net]

I'm going to find that stupid EVAP map so that people can let their fuel tanks vent in less complex ways. EVAP duty cycle is 5-10% ish at warm idle from memory.

The EVAP duty cycle actually increases with engine speed, but when into boost it is disabled - pretty sure I have seen and EVAP looking map in the boost chip somewhere. I thought it was also supposed to shut off on the overrun so that unburnt fuel vapour doesn't get sucked into the engine - the injectors are closed on overrun remember.

You can log its behaviour quite simply on VAGCOM.

[s2martyn]

does anyone (paul) have a log to compare it to if i generate one my end?..duty cycle was normal on idle(was within tolerance on labels..

[S2central.net]

I'll try to log something this weekend - weather & time permitting... Maybe I'll stick the sillyscope on it too and go hunting in real-time for the EVAP map.

[Rusty]

I've gone for a Terrybullwon style vent at the rear and it stinks of petrol on hot days, sub optimal. Not sure what other options there are really... catch tank doesn't catch FA other than water either so starting to wonder what the point it really on mine at the mo.

[S2central.net]

I don't think there is anything wrong with the EVAP system on the S2/RS2 - except all the complex plumbing and joints under the throttle body. I think a neat idea would be to keep ECU in control of EVAP and the carbon canister, but just to let it vent to atmosphere - somewhere well at the rear and outside the car - also accomodating some sort of ball valve to make sure a rollover doesn't have contents of fuel tank pouring out in a major incident.

[Rusty]

I designed my catch tank system so I could use it with the OE setup intact, all I need to do is to plumb it back into the PCV valve and get a new PCV and fire trap in there... will see if I can be bothered.

[anton]

i dont really get this carbon canister business, i see the merrits of both keeping it and taking it off. but i will eventually go with VEMS and would rather not have to sort some EVAP map out, but i also dont want my car to smell like petrol on hot days, assuming i keep natually aspirated can i not just plug it straight into the intake manifold?? or just before the throttle but after the ISV so i dont upset overrun?.....

Ant

[S2central.net]

I think VEMS supports EVAP now - or its in development. One of the VEMS developers sent me a message about it about behaviour on Motronic. Its easier on a non-turbo car for sure... Just plumb into the manifold via the carbon canister and make sure the carbon canister has a good supply of air to get sucked thru it.

[Rusty]

My old Polo GT had a vacuum operated valve on the PCV system so that it only dumped when the IM was under vacuum, this will be a simple part to get hold of and plumb in

[terrybullwon]

also accomodating some sort of ball valve to make sure a rollover doesn't have contents of fuel tank pouring out in a major incident.

Its already there, The system is far to complex to do the job it does. Just some fittings, nomex pipe or AN fuel line and a good filter will do a much better job.

As for the valve, cut and extend the wires and move it some where noisey

[Jamo]

I've gone for a Terrybullwon style vent at the rear and it stinks of petrol on hot days, sub optimal. Not sure what other options there are really... catch tank doesn't catch FA other than water either so starting to wonder what the point it really on mine at the mo.

Oh...........

[Rusty]

As per conversation the other day, there's development left on mine to do, with a little flap trimming it'll have it a lot better in the car but still smells outside