3.2 idle not steady
 

My 3.2 idles at 800 rpm but bobs up and down 2-300rpm. It also does this when cold but at 1100rpm. It just bobs up 2-300 rpm and back down. The searches I've done came up with idles that were more erratic than mine.

I've sprayed around with a can of engine starter but no change was noticed. Any one experience this particular problem? TIASmileWavy

Check that the idle microswitch consistently activates when throttle is closed. Clean out the idle control valve from any gumminess. If you don't have any vacuum leaks, then you'll need to adjust your idle mixture under the air flow meter, and readjust the base idle speed.

When it Hunts (as you stated bobs up and down), keep the engine on and use a screw driver and tap on the Idle Control Valve (ICV). If it clears, it may be gummed up as stated above or faulty.

If suspected to be Gummy, take the ICV off and thorughly clean it's inside until clear spary some lube silicon based not WD40 please. Re-install and test. If it persist do the following:

Take a digital multimeter to the electric terminal when engine is off on the ICV. The center terminal plus any of the outer terminals should read a minimum of 20 OHMs. The outer terminals should read 40+ OHMs. Simple fix just swap with new one. Check the new one before you install.

My mechanic said it could also be the O2 Sensor, my next project.

ok, I have a stupid question
where is the idle control valve located?

found it in the parts diagram
how do you clean it?

Undo the hose clamps and the wiring connection, use injector cleaner or ether and dump it in where the hoses hook up to. I used nitrile gloves to cover both ends and swirl it around inside, do this a few times until it looks clean - then use silicon base spray to lube it. Re-install. There are a couple of threads on this that explain it better than me, search for ICV. I just did this last weekend and it helped.

I am reading through the searches now.
sounds like cleaning is pretty straight forward, thanks!
but the electrical testing goes straight over my head.
I have no idea what they are talking about

Get youself a Digital Multimeter to test the terminals of the component to read proper OHM's. When you get the meter, it will explain in detail how to use it.

What's great is most meters have a "Short" indicator mode to find those annoying circuit shorts. It is a must tool.

I will do.
I try to understand the terms but it is not easy
lol

LOL, Brother,

I spent 2.5 hours last night with another memebr looking up WUR, to find out later it was not for my year, I have a WUV.

Don't be shy ask anything here, we all try to input for the P community.

I have noticed that for sure
I know I don't know
of course my biggest fear is breaking something that isn't broken when i try to "fix" it
lol

Been there Done that.

I replaced the Cylinder Head Temperature Sensor located on the #3 cylinder head and routed to the engine connected to a three connection key. I was so carefull but due to age and heat the plastic just fell apart when I disconnected it. I stayed calm and had some thick rubber heat resistant tape and taped that sucker up. It is actually add better heat protection and no risk of moisture instrusion.

Feel free to ask before you do.

I use the Carrera manifold on my turbo, my idle was doing the exact same thing when I completed the rebuild.
Try adjusting in this screw in on the throttle body, it should turn easily, don't be afraid to turn it in 3-5 turns, you can always put it back where it was, count the turns.
This solved my idle hunting problem.
Good

Luck.http://forums.pelicanparts.com/uploa...1196195478.jpg

what does it do?

It's the air bypass adjuster, by threading it in you reduce the amount of air by a small amount at idle, this circuit is bypassed as soon as you a crack the throttle.

Here we go...http://forums.pelicanparts.com/porsche-911-technical-forum/370635-carrera-3-2-idle-fluctuation.html

yeah Zef I have been reading through that thread as well
there is a ton of info on this issue
seems all different kinds of solutions are at play

just gave this a try. and it really smooths things out a lot
idle was not hunting so much but right off idle there was hesitation
now it is gone.
still need to check the ICV electrically
that will be my big achievement for sure

You can take that screw all the way in if you're getting an improvement, don't be afraid of tweaking with it.

ok, thanks again.
every little bit helps
very cool how little steps and ideas work wonders