Fast idle after a drive

[puddy]

I thought I'd post this here, wasn't getting any action the technical forums, maybe coz everybody's at Hershey?

http://forums.pelicanparts.com/porsche-911-technical-forum/861282-faster-idle-after-drive.html

[DSPTurtle]

Check that you have it plugged in correctly and that you have 12V to the connector. It will take much longer to idle down if it's relying on engine heat vs the electrically heated spring. That connector gets power from the rear fuel pump so you may want to make sure that is running also since I've seen them high idle like that when only running on the front pump.

[puddy]

Both fuel pumps are running. Today I drove the car. Let it sit long enough to cool down a little. Started it and It did the high idle thing again, so I turned the car off and started it again and it went to the normal high idle. Strange. Shut it off started it again and it was back to the high idle again!

[DSPTurtle]

Sounds like a vacuum leak...

[puddy]

OK i'll check those hoses again. But it runs fine and smooth. Just idles high until warmed up.

[puddy]

If someone plugged the wrong plug into the AAR would it work but not correctly or not work at all? I'm curious because there is a plug that's the same very near for the cold start valve, I believe?

[DSPTurtle]

The cold start valve plug is blue. It's pretty far away. It only gets powered for a few seconds so the AAR would not work properly.
The WUR connector is very close but would still require a pretty serious effort to stretch the wire. That one would work though. AAR and WUR need 12V the entire time the engine is running.

[puddy]

Ok I've just discovered the grey plug is in the black port on the AAR. And the black plug is on the grey port on the WUR, if these are color coded and I switch them back so the colour match hopefully that solves my problem!

[DSPTurtle]

There is such a thing as the placebo effect and plain old dumb luck. Fingers crossed that one of these makes your day!

[puddy]

Well I'm happy to report that after making the swap it idled fine once warm. I took it for a drive and then stopped and restarted 3 time and the idled stayed at low warm idle of 800 rpm. No more up and down with the idle, for now anyways, I think/ hope that fixed it!!

Previous owner owes me a beer!

[mark houghton]

Originally Posted by puddy

Ok I've just discovered the grey plug is in the black port on the AAR. And the black plug is on the grey port on the WUR, if these are color coded and I switch them back so the colour match hopefully that solves my problem!

Since "fast idle" seems to be my most recent challenge, I thought I would read this post. As usual, Der Turtle's advice is spot-on (I especially like the dumb luck/placebo affect...we all need some of that).

But....there's always a butt...if I'm not mistaken both the AAR and WUR plugs are identical in shape and either one will connect to either location. The key is that both must have constant 12V to them. In your case, apparently one of them had constant 12v and the other did not. By switching their location, you got your AAR to heat up as it should. Now, is your WUR receiving power as it should? And if it is, then so should have your AAR before switching the plugs.

Maybe it's just dumb luck. Me, I hate it when I can't find an "ah ha" definitive cause.

[puddy]

Well maybe it is too good to be true BUT just yesterday it was idling really high after restarting when warm, now that I swapped the plug and the colours on them match up, it's not doing the fast idle.

I tried to see if I had 12v going to ithe AAR but I honestly couldn't get a borrowed voltage tester to work, or I didn't know how to read it. I wasn't getting 12v, my screen was showing 0.1. I really know very little about auto electronics so I'll have to try again when I get a voltage tester tutorial from the owner.

[solarispete]

Hello! Did you ever find a solution to your problem?
I have very similar problem with my 930 as well.