Idle

94StealthTT · #1 12-22-2005, 07:26 PM

When I start my car it idles high until it warms up. Then it goes to about 900rpm like normal but then after I drive it a bit it will idle at 1100rpm and doesnt go back down. I have checked the BOV and it is closed at idle, the compression checks good, and I have replaced many vacuum lines(some bad). What else could lead to this abnormally high idle?

Linebckr49 · #2 12-23-2005, 01:38 AM

so it regularly idles at 900 rpm.... and 1100 rpm is an "abnormally high idle"?

Morphius289 · #3 12-23-2005, 01:44 AM

lol, mine idles all over the place, from 600rpms to close to 2000rpms when its cold. I don't think you have much to worry about.

94StealthTT · #4 12-23-2005, 01:38 PM

I guess if it is normal for it to do that than I will leave it alone for now. Over the summer it would maintain an idle at about 900rpm though so maybe it has something to do with the cold weather? There were a couple of things that could cause the idle to differ though.
Vacuum leaks, bad compression, idle adjustment, and I was wondering about the IAC. Maybe I could clean it like some others have done.

2old · #5 12-23-2005, 01:58 PM

I would say don't worry about it. The ECU on our cars is not exactly the sharpest tool in the shed and takes a while adapting to any changes in the operating environment (I think their is too much fuzzyness in the fuzzy logic controller).

If you are really bored with your life and don't get freaked out if your engine dies while waiting at in intersection you can try unhooking the battery for a few minutes and then hooking it back up.

After you do that, you car will feel like the badly tuned carborated engine for a few days (I don't actually advise you try this,but it's an interesting experience)

Morphius289 · #6 12-23-2005, 02:09 PM

Quote:

Originally Posted by 2old

If you are really bored with your life and don't get freaked out if your engine dies while waiting at in intersection you can try unhooking the battery for a few minutes and then hooking it back up.

After you do that, you car will feel like the badly tuned carborated engine for a few days (I don't actually advise you try this,but it's an interesting experience)

I've had that happen to my car(unintentionally, my battery cables are really messed up) and it's one of the weirdest things ever. The car will start out great, and then idle down to where it feels almost non existant. Then it will jump back up to around 500-600rpms. This was one of the scariest things that i've ever experienced in my car, and I've gone through some scary things. So basically...just don't disconnect the battery unless you have to. It's not fun.

Linebckr49 · #7 12-23-2005, 03:54 PM

Quote:

Originally Posted by Morphius289

I've had that happen to my car(unintentionally, my battery cables are really messed up) and it's one of the weirdest things ever. The car will start out great, and then idle down to where it feels almost non existant. Then it will jump back up to around 500-600rpms. This was one of the scariest things that i've ever experienced in my car, and I've gone through some scary things. So basically...just don't disconnect the battery unless you have to. It's not fun.

actually, you've nothing to worry about. when you disconnect the batter for a certain amount of time (i think 10-15 minutes), the ECU will reset itself. so, when you hook the battery back up and start the car, when the idle is fluctuating, that is simply the ECU "relearning" the different parameters of your car, the environment, barometric pressure, etc so it can idle correctly. i've done this several times when trying to clear a check engine light. it will take about 30 minutes of drivng the car around until your ECU "relearns" how to idle.

Morphius289 · #8 12-23-2005, 04:04 PM

Yeah, I figured it had something to do with the ECU but I was still worried. And it still doesn't idle correctly, it's been quite low for a while (600rpms etc.) Any suggestions?

94StealthTT · #9 12-23-2005, 07:29 PM

Sometimes when I start my car it will idle low and it wants to die out. This has only happened about 5 times total. I just give it some gas so it idles up then after a short while it idles normally. After reading some other posts about idling I think I might check my IAC. Seems like some of the symptoms point to it.

VR43000GT · #10 12-23-2005, 08:02 PM

Its the cold weather, my 3kgt idles at 2200 when its very cold out. When it gets warm it will go back down to 800-900rpm's.

Morphius289 · #11 12-23-2005, 08:44 PM

Quote:

Originally Posted by SL3000gt

Its the cold weather, my 3kgt idles at 2200 when its very cold out. When it gets warm it will go back down to 800-900rpm's.

He was talking about idling low, not high. And does anyone know exactly what the optimum rpms are that we should be idling at?

94StealthTT · #12 12-23-2005, 09:00 PM

I believe the rpm should 850-950 range. I dont like how people say it is normal for a '3s' to idle so bad because it shouldnt. There does seem to be a idle control problem with these cars though.

Linebckr49 · #13 12-23-2005, 09:05 PM

the service manual says 'curb idle speed (rpm) is 700 +/- 100

Morphius289 · #14 12-23-2005, 09:12 PM

Oh damn. I guess my car is idling fine then

JaceWade · #15 12-25-2005, 04:45 PM

I noticed the same thing with my TT. When I first start it up it seems to idle a little high. About 1200 rpms. And it will randomly drop and raise between 900 and 1200 rpms. My NA didn't never hadthis problem.

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