Thread: GXP whining sound, that comes and goes, does not stop the second the engine does.

This is going to sound crazy. About a month ago my wife was driving the GXP. She stopped at Walmart, did her shopping, and started the car and heard a noise. Called me, I was afraid a belt idler or tension bearing was going out. I drove there had her start the car and all sounded good. So we swap cars and I started driving it. No problems until this morning. I back out of the garage, started down the driveway when I heard the whine. My first thought was belt tension bearing, but then it sounded closer to the front of the engine. So I killed the motor and the noise did not stop with the rotation of the engine. In fact, it was more of a winding down. Then I started the car and drove it a couple of places and so far it has not done it again. Of course, it has been almost a month since the last time it did it.
Thinking about it, I wonder if it could be a smog pump?

Maybe even a cooling fan. Like if the defrost was on, the fan could also on because it's using the AC system.

Originally Posted by Fivefingerdeathpunch

Maybe even a cooling fan. Like if the defrost was on, the fan could also on because it's using the AC system.

Good point. A friend suggested jumpering the relay, but I don't think it makes the noise all the time. This may be one those issues we will know when it finally fails.

I was hoping someone could suggest something on experience. For example, if I said my low beams sometimes don't work, our first thought is the relay. Which BTW, the GXP one went bad while my wife was driving it. I was on a mission trip, so I told her I would fix it when I got back. Then she gets a recall notice for the low beam relay. She took the car into the dealer, got it fixed before I got back.

Originally Posted by SaukRapids

Your DoD might be taking a dump if still have Active Fuel Management on

Sorry, it took so long to get back to you. I have made 0 mods to the engine, so yes it should still be on. I know it uses oil pressure or lack of by closing a solenoid to effect different closing of the valves. What part of the system would create a whining sound?

Also, it did it again leaving work last Friday. That put's the last episode at about 3 weeks ago. This time I hit the hood release. Grabbed my phone and got the camera fired up to record it, and it stopped before I could start it. So I did not get any video.

I can't remember when and how the smog pump is tested. I know it a cold start and it uses the O2 sensors. I did smell a rich condition when I got out to video. The length of the noise does fit about how long the test runs. I have a GM friend with a Snapon diag tool that can command on the pump. Just getting him, the tool, and the car in the same spot can be a challenge sometimes. :-)

It did the whining sound again today. This time I did get it recorded. First thing I did was hit the record, then pop the hood, and then started looking. I posted it to youtube.
The video is 41 seconds long. Say 5 to 10 seconds to find and press record, then it was about the 30-second mark where the sound started to quit (all on its own), so I guessing the length is about 35 to 40 seconds long.
Here is the link for the whole video, Come and go car noise - YouTube , again about 40 seconds.
Here is the link where the noise starts to quit, Come and go car noise - YouTube

A couple of notes, I am guessing it started about 15 to 30 seconds after the car started. Also, I thought there was a fuel-rich smell, not sure though.
The last post was Feb 18. That puts about 40 or so days between them.