surging idle for first minute

scrambled2k3 · 01-03-2004, 08:43 AM

OK....If i can't get this problem solved myself, then i'm just gonna put the car in the shop on Tuesday. If it is warm or hot outside, and i crank the car, it bounces between 600 and 1000 RPM for about the first minute of running, then it clears off to 1000 RPM and stays there. And when its cold outside ( i live in S. Georgia, so less than 45 degrees) it starts up and idles perfectly. But if i drive it, and the engine gets warm, and I shut the car off and thank start it back up, the idle surges for about the first minute of running. Anybody got any ideas?
Also, while the idle is surging, if i turn on my headlights, roll windows up or down, or turn on my blower for the heat or AC, it causes the RPM's to drop even further.
Any help will be greatly appreciated.

CT944 · 01-03-2004, 09:03 AM

Sounds like an alternator or battery problem. How old is the battery? Does the battery light stay on for a few seconds when you first start the car?

scrambled2k3 · 01-03-2004, 09:04 AM

the battery on only a couple of months old...but if i leave the car sitting for about a week, it will barely start, like something is constantly draining the battery, but i can't find anything being left on.

CT944 · 01-03-2004, 09:08 AM

That would mean that either the alternator is not charging the battery, or something is remaining on when you shut off the car (alarm, stereo, etc). Bring it to Autozone/Pep Boys, etc and have them do an alternator test. They may do it for free.

scrambled2k3 · 01-03-2004, 09:16 AM

but it still does it even if i've been driving for a while...the volt guage on the dash still says between 13-14 volts while the car is running. If i've been driving a while and turn the car off and turn it right back on...it will start surging. The car cranks like it has plenty of power in the battery.

Zero10 · 01-03-2004, 11:28 AM

If the alternator is charging proplery, then the only other problem it could have is the diodes, which would kill the battery a lot quicker than 1 week, more like 1 day.
It is possible there is something sticking on, disconnect the battery and put an ammeter between the battery and whatever lead you disconnected, to see how big the draw is (get an ammeter that will take minimum 10-20A), and then pull fuses one at a time trying to find which circuit it is on. That should give you some idea where it is.

Sabyre · Sabyre's Garage

Are we positive that this is an electrical problem. It almost seems like I've had that problem before on another car. Turned out to be the thermal damper in the intake system. Wouldnt let cold air in after it warmed up. Of course it was throtle body injection unlike these are. Just a thought.

ronin · 01-03-2004, 12:36 PM

Sabyre, I'm with you on this one. there appears to be something more than just an electrical problem here (not saying that there aren't both). perhaps engine temp sensor or cold-start system problems

Zero10 · 01-03-2004, 05:23 PM

Ahh, good ol FR Wilk's logical advice, I was thinking the same thing, but I didn't want to guess.

Well, at least I hope I was some help on the battery dying =)

scrambled2k3 · 01-03-2004, 08:22 PM

Can you help explain to me how to reset the idle...is it anymore than just adjusting to idle screw...or is there more to it?
About testing the connector and jumper b to c...can you help explain that also cause i'm a little vague to what your refering to.
Thanks

ronin · 01-03-2004, 09:54 PM

Quote:

Originally posted by FR Wilk
your knid of problem at wrm up.

clodn't have sid it better msleff

Zero10 · 01-04-2004, 12:05 AM

It's time for me to stick my head in here with a stupid question.
The DME will adjust air flow? I didn't know it could do that. How does that work?

scrambled2k3 · 01-04-2004, 06:55 PM

My haynes manual doesn't show me...so can somebody tell me where the idle stabilizer is located?
thanks

scrambled2k3 · 01-06-2004, 02:16 PM

OK...well i couldn't get to the idle stabilizer cause i didn't want to screw something up, so i took it to my local porsche shop.
It ended up having a dirty throttle body flap, and the cleaned out the idle stabilizer valve. Now it runs very smooth and perfect. Thanks for the help guys. And by the way, does anybody know if its difficult to change out the motor mounts, cause they told me that all of mine had collapsed and it would cost around $400 to replace?
thanks

TCMdocs944 · 01-07-2004, 01:31 PM

Haven't done it yet but they cost about $50 each..

It doesnt look like that particularly difficult of a job but would probably require the purchase of a few tools (upping the price).

Most posters haven't really complained too much about it.