Vems Carbon canister freq valve

[Bram]

Is this already implemented in one of the firmware versions?

Does nobody know this?

[A80Avant]

there is a misc output with which you can control the valve.im planning to do this in the near future to see results. in any case though it doesnt make a difference. so far i dont use it and everything is fine

[A80Avant]

it could mean that the duty cycle incrases with revs so long as you are in vacuum mode when driving.As soon as you get into boosting then it shuts off.

[Bram]

there is a misc output with which you can control the valve.im planning to do this in the near future to see results. in any case though it doesnt make a difference. so far i dont use it and everything is fine

I would be interested if you get it working. I am waiting for my VEMS to arrive

[A80Avant]

im going to try it hopefully today. Im not sure if i will see any change though. Marc has given me instr. to set it up on the misc. outputs. It doesnt have a duty cycle to appoint,but i presume that by inputing high and low values it will be done on it's own.

[A80Avant]

After reading a few things about the EVAP system i realise that this basically have a general effect on richness to the mixture which on our cars, is only done during closed loop condition as the narrow band lamda can only handle that. Also it is done under vaccum and not boost as Paul mentioned for reasons being that there is not any problem with premature igniting of the fumes being under pressure.

So i am going to be testing the next few weeks this following setup:

With VEMS i have used settings of:
RPM: 1800-4000
TPS: 0-10%
kPA: 0-80

im not sure how VEMS will control the valve, but i gave these conditions in order to be operational.

What i presume this will do is that

1) it wont affect idle(becoming more rich) as it is set to work above 1800rpm
2) during cruising and vaccum the fuel fumes will be entering the IM thus making the mixture richer BUT on wideband lamda control the mixture will be brought back to normal
3) Under boost the valve will be closed (even sooner than that)
4) on deceleration fumes will be entering the IM.

im going to post any findings soon

[A80Avant]

after a quick ride i couldnt feel any difference with these settings so far. I may increase the TPS value a bit just so as it works a bit more (if needed)

[A80Avant]

a small update on this.

unfortunatelly, since vems does not have the ability to modulate the duty cycle of the valve, it appears that it works 100% on the specified settings.
thus, when i use TPS up to 15% operational valve, the car goes a bit woobly on low speed in town cruising.

Therefore i have decided to go for only vaccum use of the valve, hence 0-2 TPS values and low kPA so that it only opens up completelly on deceleration.At least that way some of the fuel fumes buildup will be burnt.

However,i think our tanks must have a small tube that allows fumes to go off anyway, as if not, all those cars that disable the valve due to aftermarket ECUs, would eventually or potentially have a major problem, right?

[Bram]

a small update on this.

unfortunatelly, since vems does not have the ability to modulate the duty cycle of the valve, it appears that it works 100% on the specified settings.
thus, when i use TPS up to 15% operational valve, the car goes a bit woobly on low speed in town cruising.

Therefore i have decided to go for only vaccum use of the valve, hence 0-2 TPS values and low kPA so that it only opens up completelly on deceleration.At least that way some of the fuel fumes buildup will be burnt.

However,i think our tanks must have a small tube that allows fumes to go off anyway, as if not, all those cars that disable the valve due to aftermarket ECUs, would eventually or potentially have a major problem, right?

You could make a pipe that dumps it below the car maybe?

[A80Avant]

i think i have seen that pipe being there already,hence if the valve is not working,the fumes have a way out.

i have definitelly seen one on older audis again from 1994

[GazzaG60]

just thread the pipe into the wheel arch.

the vapours are not enough to upset the mix in the scheme of things. you would be talking less than 0.01lambda id expect.

the theing that may affect it is the vacumn change..

just rip the fecker out. what benifit is it doing trying to make it work. i can see the challenge prospective to it but there are a lot more worthwhile challenges on these cars.

[Bram]

So what you are saying is remove the carbon canister freq valve and put a catch tank in between somewhere? That sounds like workable to me. Should there still be something that vents the sump some how?

[GazzaG60]

the carbon can wont require a catch can. its petrol tank breathing. also ask yourself is the carbon still working after all this time

the line from the tank can be fitted with a little filter and tucked away. no filter required really. dont block the line the venting helps.

block all the vac ports on the manifold with pipe or buy some of the vac blockers from the stealer for diesels. remove the extra mess in the engine bay.


the whole system is to burn off a little more and be more environmentally friendly. the fact we run higher hp, bigger exhausts, more fuel etc means we have more than exceeded any benifits we were doing. tree huggers pedal bikes after all and id expect boil the designer of S cars in h2O

[Jamo]

Does this work? and if so what injector output was used to control the EVAP valve?

[A80Avant]

it works for me using the misc output and on overrun only. no problems so far, and getting some use of the system