Whats this part for?

[Cnut 0]

I have noticed with the engine running that I can hear air gushing out of this part and when you place your hand over it, it seems to stop.

 

Just wondering if it is anything serious?

 

Car is a 95 VR6

[Guest]

YES BUT WHAT PART R U TALKING ABOUT ?????

[RW1 0]

Hi,

 

It's known as the Idle Stabilisation Valve Damper. Tuned sound deadening part.

 

Blowing like it is means it's bust and also you have a problem, it should be air tight. Possibly the ISV is sticking or an inlet valve is leaking giving rise to higher pressure in the inlet manifold or it has simply given up with age to the airpressures inside.

 

New part replacement.

[dr_mat 0]

Do what john?

Damper?

Is it broken?

Eh?

Mine has made a whooshing noise since I got the car three years ago and it's never made any difference to the running (as far as I can tell!).

Anyone else with an opinion? (cos clearly I can't see straight enough to express one)

[RW1 0]

Yessss, it's sealed no air leaks when new. Yesssss it's a noise damper.

 

What's your idle speed like? Rough or smooth?

[Cnut 0]

YES BUT WHAT PART R U TALKING ABOUT ?????

 

Follow the red arrow on the 1st pic :roll:

[Cnut 0]

Yessss, it's sealed no air leaks when new. Yesssss it's a noise damper.

 

What's your idle speed like? Rough or smooth?

 

Thanks for your help,

 

Idle speed is very steady, only thing is a slight hesitation at low revs but im not sure whether it would affect that?

[dr_mat 0]

Me too, no idle problems to report other than a very slight misfire every so often.

Damn, any idea how much that part is? No doubt VW only sell it with the whole damn assembly ...

 

Now I think about it though, despite it making whooshing noise (which is reduced when you hold the thing), I don't know that it's actually *leaking* as such. Maybe it's just making a noise indicating that air is flowing through it?

 

How is all that tubing connected to the ISV? What route does the air take through it all?

[RW1 0]

only thing is a slight hesitation at low revs but im not sure whether it would affect that?

 

Could as the ISV air circuit supplements the induction at low rev's to aid a smooth take up.

 

Also hestitation (if it is at revs just above idle) sometimes is caused by the throttle not being harmonised to the engine ECU. If you have access to VAG-COM, try carrying it out Basic Settings (04) on either group 000 or 001 depending on your ECU part number. See bottom paragraph notes of ECU Reset procedure in Knowledge Base for which ECU goes with which group. Basically put the ECU into BAsic Setting mode, select the group, open the throttle upto 3,000 rpm for 3 seconds and then leave to idle for further 2 minutes, exit basic settings while the radiator fan is not running. Job done. Costs you nowt other than 15 minutes of your own time and at least you've eliminated that.

 

 

 

dr_Mat - As far as I know, it's VW part only.

[Dutch24V 0]

It's supposed to make a wooshing noise and I believe it gets quieter when you put your hand over it due to the sound insulating qualities of your hand!

 

I had the same and thought mine was leaking causing my rough idle, but when I fitted a new one as a test it did the same. If you cannot feel air (make your hand wet and cover it again) then it's not leaking, but they do make a noise simular to an air leak which doesn't help!!

 

Dutch

 

BTW, How old is your MAF? ...a slight hesitation at low revs could be due to a dodgy one as I've recently discovered (and it won't give any errors on VAG-COM either)

[dr_mat 0]

Yeah, I checked my damper thingy out and it's definitely not leaking air, it just sounds noisy.

But it's not as noisy as the K+N 57i, so hey who cares.. :)

I wonder if a new MAF would help clear up the pinking I've had since fitting the Schrick sometimes too, but it's a bit of a pricey "buy-it-and-see" ...

[Andy T 0]

Anyone else had problems with this ISV damper, or found it to be the cause of a rough idle?

 

I noticed last night that it seems to be drawing in air slightly, but after reading this i'll check again. Anybody know the rough cost?

 

Cheers

[martyjmcfly 0]

Mine exploded first time when i did something silly then i knackerd another one because the problem is still there sort of but ok :)

 

the head just needs a clean that all.

 

if you have extra air being drawn in then i reckon it will cause a rough idle. When my first damper blew some of the blue foam from within the case blocked the ISV open and i had a very lumpy idle. Whilst doing the work to sort this out check the ISV.

 

The part costs approx £22 from memory, the part number is on the underside.

 

I have removed it from the excellent advise from kevhaywire. You just rotate the ISV and connect the rubber tubing that originally connected to the damper and hay presto. You notice a slight whistling but it sounds kinda cool like a baby super charger. I have had it this way for 6 months + and have had no problems. The damper must do as said on the tin and supress the whistle noise.