Magnetic vacuum valve NF

[Viper109]

Hello guys,

I have some trouble with my magnetic vacuum valve (I think). For good measure it is for part nr: 3911070906. It's from an 1988 Audi 100 with new NF engine.





It connects hoses from the carbon filter and the throttle valves. When the engine is running it makes a regular ticking noise. Hereby I measured the signal and got the idea that there is also comming a pulse signal from the source. My volt meter is too slow though to get an accurate reading of the true signal. I might run it through a scope soon though.

My problem is that I have some idle stabalisation problems while engaging the clutch and some cold start problems. (I might make a separate topic on that) I can't really seem to find what this valve actually does and what signal it should get. should it tick so loudly and rapidly? At first I though that the ticking sound was a valve, so that's the kind of sound you can expect. Does this harm, and does it have influence on idle running for example bypass air running into the air intake? If someone have a diagram of the signal this valve should get would also be very helpfull.

Thanks in advance guys!