Vibration While Idling

FlipMan · 09-02-2006, 03:52 AM

I have an 03 Optima SE that just broke 40,000 miles. While idling I get this really strong vibration. When I put the car in neutral it goes away. But once back in drive it does it again. It only happens when I'm at a full stop and not while driving. I just bought the car 3 weeks ago and I'm the second owner. Do you think it might just need a tune up? Or could it possibly be the timing belt? Other than that the car drives great and I love it.

Also as a second owner. What exactly is covered by the 5yr 60,000 mile warranty from Kia? Any help would be greatly appreciated. Thanks...

ron1004 · 09-02-2006, 04:42 AM

Your idle problem sounds like a sticky Idle Speed Control valve.

The ISC is in parrallel with the throttle butterfly, and when the ECU sees the TPS showing closed (idle position) it will modulate to hold a steady idle speed regarless of changes in load such as the A/C switching on and off, and in the case of an Auto, putting it in Drive.

Most often just cleaning the throttle body and ISC with carb cleaner sorts it out.

Check this site for more info
Global Service Way

FlipMan · 09-02-2006, 06:54 PM

Quote:

Originally Posted by ron1004

Your idle problem sounds like a sticky Idle Speed Control valve.

The ISC is in parrallel with the throttle butterfly, and when the ECU sees the TPS showing closed (idle position) it will modulate to hold a steady idle speed regarless of changes in load such as the A/C switching on and off, and in the case of an Auto, putting it in Drive.

Most often just cleaning the throttle body and ISC with carb cleaner sorts it out.

Check this site for more info
Global Service Way

Thanks for the reply. I'm checking out the schematics right now through the link you gave to the kia usa shop. Looks pretty simple to get to and clean. I'll give it a shot. One thing I did notice today is that it only does it after driving for a few minutes. It doesn't do it when I first start the car and sit there idling.

Also I have the infinity sound system in the car. Is it me or do the rear speakers seem weaker than the fronts? I've checked the fade and everything is balanced. The rears just seem weak and somewhat garbled. I checked the cone and the wiring and they seem fine, in fact they look really good. Doesn't mean they aren't AFU though.

Thanks...

ron1004 · 09-02-2006, 09:22 PM

Quote:

Originally Posted by FlipMan

Thanks for the reply. I'm checking out the schematics right now through the link you gave to the kia usa shop. Looks pretty simple to get to and clean. I'll give it a shot. One thing I did notice today is that it only does it after driving for a few minutes. It doesn't do it when I first start the car and sit there idling.

Thanks...

A sticky ISC valve is only one of a number of possiblities, and it is best diagnosed using a scan tool (not code reader) that can indicate the sensor inputs with the engine running.

Your mention that the problem appears only after driving a few minutes, may point to a bad O2 sensor.
The O2 sensor only starts working once it's warm, and because of this the ECU waits about 2 minutes after the engine start before using the O2 signal for fuel/air ratio control (open loop control), and in this time it uses a fixed value for fuel/air ratio (closed loop control).
The O2 signal can be confirmed using the scanner.

No idea what could be your problem with the audio, but I'm sure others on the forum could help.

Cheers.

FlipMan · 09-03-2006, 02:34 AM

Yeah I might just take it to the dealer and have them check it out. I'll tell them about some of things you've mentioned just to maybe point them in the right direction.

zackdimovitz · 11-02-2006, 07:57 AM

How do you do those things you said to make the vibration stop while idling?

ron1004 · 11-02-2006, 09:31 AM

Quote:

Originally Posted by zackdimovitz

How do you do those things you said to make the vibration stop while idling?

Do what things?

Describe clearly the symtoms of your problem and that way you're likely to get expert help here.

zackdimovitz · 11-05-2006, 03:55 PM

When my car idles, either at a light or if we're waiting for someone by a house with the car on, it vibrates hard. You can feel it alot more than before.

ron1004 · 11-05-2006, 06:10 PM

Quote:

Originally Posted by zackdimovitz

When my car idles, either at a light or if we're waiting for someone by a house with the car on, it vibrates hard. You can feel it alot more than before.

I suggest you take it to your nearest service center to get it checked out.