Strange noise from ISV....???

[LHD_Kid]

Hi again....
Almost thorugh the list of problems now.,...
Car running pretty well now, and maybe this has arisen because I am paranoid about things and am more closely monitoring everything...
When the engine is stopped after running for even a few moments. half a second after the engine stops there is a loud metallic click from the ISV, just once, but every time. I have never noticed this before, is it normal?
Sounds like a butterfly valve snapping shut, quite high ptiched, but really quite noticeable...
Any ideas?
I am sure if it was doing this before I would have noticed...
Thanks for any advice.

[iain1067]

Mine does it on my S6 i would say it's normal almost like a brrrpppp sound??

iain

[LHD_Kid]

Mine does it on my S6 i would say it's normal almost like a brrrpppp sound??

iain

Hmmm.... not sure really.... hard to describe sounds, but definately is a metallic snap shut sound, with the bonnet up and hand on the ISV when somebody else shuts off, you can even feel it...
I guess it might be normal, as clearly there is some kind of sound, just wondering if it is ok...!

[A80Avant]

in order to really notice if it is the isv you can run a test on the diagnostic(vag com too) i have the VWtool that among other things runs a test on the isv making it work as it works when the engine is running.It does a clicky noise so if you test it you can understand if this noise is the ISV making it.By the way it is a perfect way to spray clean it as well! gets the carb cleaner in all internal moving parts of the ISV!!

[iain1067]

Can also be done doing the ecu output tests manually with a couple of bits of wire, well you can on the S6/S4

iain

[iain1067]

I can see me having an away day to focsani............. lol

[jameswkr]

If you test your ISV (off the car) using a 9v battery it will open and shut fast with a sound - as you describe - as it overshoots and hits the stop before stopping at the "limp home" 2mm open setting. Never heard this on my car ( and Ive had a "spot" of idle problems over 5 years ). If the motor works OK why worry ? James.

[S2central.net]

Are you sure its the ISV ?

Reason I ask is that there is a very audible click when a special relay (inside ECU) is used to trigger the superheat cycle on the MAF wire - this is used to clean it after a run.

In saying that I have heard other cars with a very audible click on the inlet side of things - it could be ISV... Have you tried disconnecting the ISV before shutdown to isolate it ?

Paul

[Graham]

My ISV has doner this since i got the car in 2001, it sounds like a ball bearing bouncing off a steel plate sort of noise, i traced it to the ISV, and presume it is just going from open where the engine is ticking over to closed (Rest)