Vems Carbon canister freq valve

[peter_jensen]

Does anyone know how the Carbon canister freq valve work an when is it active?
S2
My plan is to control it by Vems



Peter

[S2central.net]

I've seen duty cycles of the order of 5-10% on the EVAP valve, but its important to know it is only used when the manifold is in vacuum.

On an ABY/AAN or ADU you can easily log this with VAGCOM to study further - I've never paid much attention to it...

[GazzaG60]

why not just put that old charcoal in the bin.

[S2central.net]

That would be an alternative approach alright

[anton]

sorry for the stupid question but what oes the carbon canister do?? isn't it something to do with fuel tank pressure relief or am i confusing it with something else??

Ant

[S2central.net]

Close but no cigar...

The carbon canister treats any petrol fumes/vapour that build up in the tank and allow them to be burned by the engine at certain times.

In the old days a petrol tank just had an air vent via a small tube to stop build of vapour pressure in the tank getting dangerous - such as a car parked up on a hot day. Nowadays it is viewed as a heinous crime to allow such untreated fuel fumes into the atmosphere...

[anton]

ah ok, that makes sence, but surely when running VEMS or i assume any other after market ECU the canister doesnt function? does this not create dangerous pressure? also is it not potentially angerous to remove it?
i'm by no means having a dig at after market systems here, especially not as your trying to include it, just trying to figure this one out.

Ant

[peter_jensen]

vems

Thanx Paul

It should be wary easy to control by Vems. Then. I will power it on below 100 kpa. And above 2000 rpm so it don’t infect the idle. Then it will be active in a small window when leaving the throttle.
Due this sound ok ?

[GazzaG60]

it does little harm to remove it.

keep the pipe from tank open. block all the others or better still remove them and block at the inlet to make it cleaner to look at. also potentially ridding you of some mini vac leaks.

the can after all this time much like a water filter is useless anyway.

we used to remove the can on the G60 corrados to free up the space in the inner wing area for filters. also removed lots of lines around the inlet.

[anton]

anyone have a picture of where this ipe is on the engine bay? or is it the line that travells down the car with the fuel lines??

Ant

[S2central.net]

Yep - its the third line from the tank towards engine bay... On an ABY the evap canister hides behind right front wing, but on 3B its way up front of the engine in a bizarre location from memory. If you follow the pipes you'll see where it comes to the IM near the throttle body - there's a blue coloured connection where it meets up with the PCV pipework.

[S2central.net]

Did some quick testing of this at the weekend.

I confirmed the EVAP duty cycle is ZERO under any positive boost.
Its about 5.5% cycle time at idle - its NOT gonna interfere with mixture in any significant way.

The duty cycle increases with revs - dont really know why - its not like there's more fumes to be treated at higher engine speeds. I think I have a log file for that data.

[lind4hl]

i think i will remove this from my car, (ADU). i need the space there. goes all hoses to the inlet manifold?

[Bram]

Thanx Paul

It should be wary easy to control by Vems. Then. I will power it on below 100 kpa. And above 2000 rpm so it don’t infect the idle. Then it will be active in a small window when leaving the throttle.
Due this sound ok ?

Is this already implemented in one of the firmware versions?

[KRIENG]

Pls. Help me
I think it show (%load). But what block No. tells N75 duty cycle in VagCom meassure block.

Let me know if you have complete description about Block Numbers.
(S4S6 are not same as 1.8T,TT)

Thank for your helpful.
S4 Y92 Manual Chiped 264hp 1.9 Bar Spring