Testing Idle Control Valve
 

Anyone have a good method for testing the idle control valve? When I supply power to outer two posts the aperture opens and closes which I think is good. I thought I read somewhere that putting the valve in the freezer should cause the aperture to open? With the intake off I'm going to replace hoses that are cracked/brittle but don't want to replace the valve if I don't have to ($$$).

jmd_forest did the same power test you have done and cleaned the ICV (ISV) with carb cleaner. Post #5

http://forums.rennlist.com/rennforums/924-931-944-951-968-forum/450557-cleaning-the-idle-stabilizer-valve.html

I refer to this post because he also replaced the really expensive hoses with a less expensive set from NAPA. Get new rubber mounts as well. His suggestion will save you lots of money.

Without purchasing a new ICV the power test and cleanout is about all I know of. After you clean the ICV you might want to squirt a bit of WD40 to lube.

I am confused by the freezer test. If the DME computer sends a voltage signal to the ICV to open, why would freezing do the same?

GL
John_AZ
1988 924S + 1987 924S

john_AZ, thanks again for great info. I was just about to order the more expensive hoses from our host (about $50 total), but will check NAPA and others first. By rubber mounts, do you mean hose clamps? Also, what about the AOS gaskets, is it detrimental to have OEM stuff or can I use any appropriate gasket?

Finally, the freezer thing I read made sense before I took the valve out and looked at it, as you said the DME sends power to the valve opening or closing it accordingly. The post lead me to believe the valve opening would contract or expand depending on temp (via thermal expansion, like in a fan clutch), open when cold, closed when warm.

Check your idle control mounts for cracks. They may be dried out and it is difficult to change with the intake manifold on. These are also expensive, there may be a VW interchange.
http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=928-110-191-10-M100&catalog_description=Rubber%20Mount%20for%20Id le%20Control%20Valve%20%28%32%20per%20car%2C%20sol d%20per%20each%29%2C%20%39%32%34S%2C%20%39%34%34%2 0%28from%20%32%2F%38%35%29%2C%20%39%34%34%20Turbo% 20%20%0A

Hose clamps. Do not skimp,get good clamps. Maybe use fuel injection clamps on big hoses or quality screw German OEM type-not the flimsy screw type. Vibration and leak prone area. Many of the original factory "pinch" type need replacing to pinch the hose tighter. (VW interchange?)

AOS seals-Go with Porsche. Again with the manifold off it is an easy job, why take a chance on a generic "O" ring that may deteriorate in the block due to heat?

Good luck,
John_AZ