Adjusting cold idle - how to do?

[Knudsen]

My idle is roughly 2500 rpm when cold... How do i adjust that a bit down?

[Ivan141]

The main reason for the astronomical cold idle (trust me we all know it) is the auxiliary air valve on the throttle body (little cilindrical bit on the bottom of the housing). This thing is an air bypass that closes when the engine gets to a certain temperature (using a wax element).
I've seen some guys on an MR2 forum putting restrictions in the inlet hole of this valve (just in front of the throttle plate), That brings the rpm's down a bit, but must be done right cause you dont want the item doing the restricting getting sucked into the engine.. I believe they glued some rubber cap in or something.

[SutteR]

Ivan141 Wrote:The main reason for the astronomical cold idle (trust me we all know it) is the auxiliary air valve on the throttle body (little cilindrical bit on the bottom of the housing).

Is this the thing attached to throttle body with two short vacuum hoses?
My idle is a bit strange too...about 1500-1800 warm until hitting the gaspedal a bit...then it drops to ~1100. I don't like it because I don't know its reason.

[ZaX]

SutteR Wrote:

Ivan141 Wrote:The main reason for the astronomical cold idle (trust me we all know it) is the auxiliary air valve on the throttle body (little cilindrical bit on the bottom of the housing).

Is this the thing attached to throttle body with two short vacuum hoses?
My idle is a bit strange too...about 1500-1800 warm until hitting the gaspedal a bit...then it drops to ~1100. I don't like it because I don't know its reason.

Yes, 2 hoses, but not vacuum/air, but water is inside.

[SutteR]

Water? Then this is the reason for that two 'not so thin' hoses being there. They come from somewhere deeeep to the bottom of the throttle body.

[Knudsen]

Ivan141
Could you please take a picture of the inlet youre describing?

[Ivan141]

I'll try and take a picture this weekend...(if I remember to). I have an AE92 GTI throttle body lying around at home (has the same valve on it).

[NickBW]

Got those pictures yet?

[Ivan141]

Nope sorry...I am a forgetfull person sometimes.

[205t16]

i recently installed a new engine in my 86 and for some reson my idle speed when warm drops from 1100 to 1000 every couple of seconds up and down. any ideas on why this might be happening.