High idle issue with a 3.2
 

My car has always had a high idle when I come to a stop. Around 1200-1300RPM. If I blip the throttle it settles down to around 1000-1100 RPM. I noticed if I take the oil cap off it drops to 850-900 RPM which I assume is normal? Put the cap back on and it jumps back up. What does this mean? For reference its a 1986 US 3.2 in a 1973 911.

Shawn, I fought this battle for about a month after I rebuilt my 3.2 over the winter. It is normal for the rpm's to drop when you take off the oil cap. After much checking of the entire system it turns out that my idle adjusting screw was turned out way to far. I had a burnt valve and maybe the idle needed to be adjusted to compensate for that in the past. I ended up turning my idle screw in about 9 turns!

Ahhh! This engine was rebuilt before they put it in the car. I wonder......
Where is the idle adjustment screw?

Shawn:

This was just recently discussed here and should give you what you need.

http://forums.pelicanparts.com/porsche-911-technical-forum/160118-how-do-i-test-idle-control-valve.html

Tim

Shawn, Look at this thread.

http://forums.pelicanparts.com/porsche-911-technical-forum/112494-news-flash-fellow-pelican-solves-hanging-idle-mystery.html?highlight=idle

Jeff,
I think that might be it..... Do you have any photos of the switches? Or a detailed desciption of what it looks like or location? Thanks.

Did you see this post today? http://forums.pelicanparts.com/porsche-911-technical-forum/112494-news-flash-fellow-pelican-solves-hanging-idle-mystery.html

Hugh,
Yeah that is the thread Jeff pointed out. I subscribed for future reference.

Shawn, I'll go take a picture and have it up in a little while.

Shawn, Remove the plug in the photo that I mark with orange. Check continuity between the two switch terminals. There should be continuity when the switch is at rest and it should not have continuity when the throttle is moved from idle position. When you return the throttle to idle you should have continuity once again. Try it a few times. If you don't have continuity at idle on any of the trys, you have found your problem. The fixes are...

1. try spraying idle switch with contact cleaner (electical not eye ball ;) )

2.adjust clearance between throttle arm and switch

3.replace switch

P.S. - the switch is located on the opposite side of the throttle body than the plug. It is a little black box that the throttle arm will rest near (just trace the wire and you will find it)

http://forums.pelicanparts.com/uploa...1083866049.jpg

Jeff,
Thanks! Now for a stupid question....Do this with the ignition on but the engine off?

Shawn, Engine off. I don't think it matters if the key is on or not.

Where in Michiana are you? I will be traveling back to that part of the country this summer.

Warsaw, IN. Orthopedic capital of the world!

Are you sure it's not just overjoyed to be blue ?!?

Great looking results BTW...