3.2 Idle Speed Adjust Screw

[Flat Six]

Just a PSA. Was resetting base idle speed on the Carrera and as I was making the adjustment I heard a little wooshing/hissing coming from the idle speed screw area.

Wasn't sure if this sound was an actual air leak from atmosphere (e.g., false air) or just the sound of additional air inside the TB bypassing the screw. So I pulled the screw completely and thought I'd post some pics in case they'd help someone else:

Idle Speed Screw:


O-Ring dimensions:


Since I already had it out I went ahead and replaced the o-ring w/a fresh one and reinstalled w/grease on it and the screw threads. HTH

[dan88911]

Thanks, Flat six

[Koizumi]

Yes thx, nice info

[wazzz]

Thanks

[fallingat120mph]

Has anyone found a replacement o ring?

I see kits online, just wondering if anyone has found a suitable replacement.

Thanks-
Erik

[fallingat120mph]

Originally Posted by Flat Six

Just a PSA. Was resetting base idle speed on the Carrera and as I was making the adjustment I heard a little wooshing/hissing coming from the idle speed screw area.

Wasn't sure if this sound was an actual air leak from atmosphere (e.g., false air) or just the sound of additional air inside the TB bypassing the screw. So I pulled the screw completely and thought I'd post some pics in case they'd help someone else:

Idle Speed Screw:


O-Ring dimensions:


Since I already had it out I went ahead and replaced the o-ring w/a fresh one and reinstalled w/grease on it and the screw threads. HTH

And yes, thanks for posting this!

Erik

[88911coupe]

If you remove this to replace the o ring how hard is it to reset the idle correctly? Do you try to put it back in in as close to the same depth as possible?

[fallingat120mph]

Originally Posted by 88911coupe

If you remove this to replace the o ring how hard is it to reset the idle correctly? Do you try to put it back in in as close to the same depth as possible?

I think some just count the revolutions upon removal to get it close and then go through the procedure of setting base idle.

I have removed before (to inspect) and had no issues going through the reset procedure. Idle was high at first and corrected from there. 800rpm in my case.


I ordered a set/variety of o rings for this from "the internet" so hopefully one comes close.

[mysocal911]

Originally Posted by fallingat120mph

I think some just count the revolutions upon removal to get it close and then go through the procedure of setting base idle.

I have removed before (to inspect) and had no issues going through the reset procedure. Idle was high at first and corrected from there. 800rpm in my case.


I ordered a set/variety of o rings for this from "the internet" so hopefully one comes close.

No need for a "procedure"! When fully warm, just turn the idle screw fully in, and back-out until idle is 800-825.
Then rev the engine a few times and make sure it doesn't "hang" at a higher RPM than the setting.

[88911coupe]

So Dave, would I just remove the idle speed screw, add the new o ring and put it back in fully seated, then start the car and drive around till its warmed up and then back it out till a steady 800 rpm?

[mysocal911]

Originally Posted by 88911coupe

So Dave, would I just remove the idle speed screw, add the new o ring and put it back in fully seated, then start the car and drive around till its warmed up and then back it out till a steady 800 rpm?

Works every time.

[Lyle O]

Please be careful on the O-ring you use; it should be Viton or similar flurosilicone material, as hydrocarbons could eat away at EPDM or TPE/TPV "off the shelf" O-rings from hardware stores, etc.

[fallingat120mph]

Originally Posted by Lyle O

Please be careful on the O-ring you use; it should be Viton or similar flurosilicone material, as hydrocarbons could eat away at EPDM or TPE/TPV "off the shelf" O-rings from hardware stores, etc.

The o rings I found are 'nitrile-butadiene' rubber...should be okay. (?)

Not exact specs so we shall see how they work. I just know the current o ring is shot.

[Lyle O]

Nitrile is a "poor man's" Viton / FKM. Should be fine OK in this application, but it will now depend on how anal you want to be. Viton is best, though.

[fallingat120mph]

I will dive further down the rabbit hole as weather is keeping me from the yard and garage work

Thanks!

[fallingat120mph]

Originally Posted by Lyle O

Nitrile is a "poor man's" Viton / FKM. Should be fine OK in this application, but it will now depend on how anal you want to be. Viton is best, though.

Or...I'll just order a replacement for 10 bucks from our host!

[88911coupe]

I have a large assortment of the "green" AC o rings...would that material work?

[Lyle O]

Those are likely HNBR (typically green color); very similar in performance to nitrile. Not as good as Viton / FKM, but probably OK here.