Thread: A little input from the experts..

Hi everybody. I've had my GP GT for a little over a month now, and I'm loving it. However, a friend and I noticed something the other day that sort of..worries me.

We were cleaned my car in and out - under the hood compartment, ever crack and crevice, everything. We fired the engine up and it started like it does when you tap the key over. (This is an '04 GP GT). It then suddenly died..I was freaked out. He tried it again and no problem, it started up right away. It had never done this to me before, and it hasn't happened since. So, I figured it was a freak thing. We then noticed something else. When you fire the car up once in a while, it'll seem like it's about to die before it revs back up to life. I don't know if that's normal or not, but it'll only happen while the engine isn't very hot. Whatever. But here's the freaky thing - whenever you kill the car, you'll hear a sort of 'rubbing' noise, as if something is spinning. My friend thinks my alternator is going bad.

He's thinking the spinning is the bearing spinning inside the alternator, and thinks I'll probably be replacing it soon. (The fact that you can hear it spinning probably means the bearing's going bad, right?)

Now, here's where I really need your guys' - the expert on GPs - help. Do you think it's an alternator problem?

Remember:
1) It didn't start up when the key was tapped - but it only happened once.
2) It'll sometimes sort of 'die down' then rev back up to live, but not every time. Maybe this is normal, I don't know.
3) I'm hearing a sort of rubbing, spinning sound when I kill the car. We've pinpointed it to the area of/around the alternator.

I'm thinking I'm going to hook up a DMM to find out what the battery is reading at idle. If it's an alternator problem, would it show up there? What are some other ways to find out if your alternator might be going out?

My dad wants to get it profesionally checked out, but I don't want to spend $50 on a diagnosis when it could possibly be a cheap fix. What do you guys think it could be? How much would it cost to replace an alternator? Might it be a smaller problem, not even the alternator at all? I can try to upload a video of the sound sometime, maybe tonight or tomorrow.

Any and all input is appreciated!

EDIT: Here's the video: http://www.youtube.com/watch?v=TvCF2...ature=youtu.be

It seems like it's coming from the alternator's area, but I'm not 100% sure. Any of you recognize the sound? My bud thinks it's the bearing inside the alternator.

Try pulling your throttle body and cleaning it.

Originally Posted by dsmuts

Try pulling your throttle body and cleaning it.

Throttle body? I realize I belong to a GP forum, but I've got a LOT to learn..

you got the a/c on when you shut the car off? sometimes you hear air or something. like vacuum escaping after you turn the car off.

the alt wont have anything spinning after the engine is off, the belt spins the armature inside the alternator, its spins in roller bearings pressed into the case of the alt. when they go bad it will squeal. take your belt off and spin the alt pulley, if it spins smoothly its ok bearing wise.

when you hook up your tester to the battery when the car is running, you want to see it charging at 13 volts or better, but not to much over 14 volts.


clean the TB for sure. behind the butterfly is where all the carbon build up is, and the back of the butterfly. removing the TB is the best way to clean it.

if you hosed your engine down while cleaning. you may have bad wires on the sensor plugs, and the water made it run funny till it dried up some maybe. for the freak no start thing.

cleaning the maf is also a good idea. use maf cleaner only.

I'm with the guys.

Your issue isn't the alternator. I wouldn't even bother taking the belt off, because many of them squeak when you spin them w/o belt tension on them. It's not a fully conclusive test.

The car died once: Doesn't honestly mean anything. I would ask..how many times do you think you turned the key on and off while you were cleaning it that day before trying to start it again. Each time you turn the key from off to on etc, you prime the fuel pump and shoot some fuel into the cylinders. That can cause what you encountered.

AC noises, fan rolling to a stop if it's on (which it would be with AC on) etc etc. There are noises you car can make when you turn the key off. It's pretty normal.

Originally Posted by BillBoost37

AC noises, fan rolling to a stop if it's on (which it would be with AC on) etc etc. There are noises you car can make when you turn the key off. It's pretty normal.

I appreciate all the input you guys have given me, I really do. I'll try to do my best to find the problem, and I hope to get a video up today of the noise. It just seems weird to me because my buddies GP (his is an '06, mine's an '04) doesn't make the sound. I've never heard another GP do it, we've had several in the family.

UPDATE!

Finally got a video taken. I made sure the A/C is off, so you know it's not the fan for that.

'04 Grand Prix Odd Noise - YouTube

I couldn't really hear anything but was the engine warm? Were your electric fans on at all?

Originally Posted by dsmuts

I couldn't really hear anything but was the engine warm? Were your electric fans on at all?

You didn't hear that sound after the engine shut off? I can hear it fine in the video. I did it twice because the first time I killed it, you begin to hear the noise, but a car drives by. The fan for my radiator wasn't running, nor was anything for my A/C. (You can hear it around 0:54)

Engine from a cold start.

Maybe have someone hold the camera for you so we can see/hear it better?

i hear a engine rolling still with no power kinda sound as its turned off. like your idle is to high. what are you idling at?

i just drove mine, and listened to mine as i shut it off, and its just turns off, no extra noise.

Originally Posted by scottydoggs

i hear a engine rolling still with no power kinda sound as its turned off. like your idle is to high. what are you idling at?

i just drove mine, and listened to mine as I shut it off, and its just turns off, no extra noise.

I really don't feel like going outside right now, I'm in a lazy mood. IIRC, it idles around 700 or so, well below 1k rpms.

I'll take another video when I can, I don't understand why you guys can't hear it. Anyway, maybe I'll have my brother help me with another sometime.

any chance you have a car with California emissions? all sorts of extra vac lines from the air box area.

idle should be about 800 in park.

i do hear a whooosh when it turned off. no idea wtf it is lol

Alright, I've got an update. I'm at my dad's place right now, and he and I just looked over it for a quick 5 minutes. We're gonna get more in-depth tomorrow about it, but I had him feel around the engine when I shut the car off, and he said he didn't feel any vibrations coming from the alternator after the car was shut off, so we're not thinking anything is spinning in there. If I don't have to replace that, I'm happy. I realize it was a pretty simple process, but I can't exactly shut the car off and look under the hood at the same time. Anyway, I'll put a video up tomorrow of the sound again, hopefully you guys will be able to hear it better this time.

Originally Posted by scottydoggs

any chance you have a car with California emissions? all sorts of extra vac lines from the air box area.

idle should be about 800 in park.

i do hear a whooosh when it turned off. no idea wtf it is lol

That seems about right, and that whoooosh after the shutoff is what's worrying me. A friend thought it was the bearing in the alternator after shutoff, but I don't think it's the alternator. I'm charging at 14v even (idling). That's around where I'm supposed to be, right?

14 volts is good.

Originally Posted by TJeno

and he said he didn't feel any vibrations coming from the alternator after the car was shut off, so we're not thinking anything is spinning in there.

Told ya so. If you'd like advice...we are here to help you. Please..understand we have lots of experience with these cars. The only things you are going to find having power, making noise or spinning after the car is off are the fans, the ac may be equalizing pressures, exhaust ticking, maybe an air pump running.

Originally Posted by BillBoost37

Told ya so. If you'd like advice...we are here to help you. Please..understand we have lots of experience with these cars. The only things you are going to find having power, making noise or spinning after the car is off are the fans, the ac may be equalizing pressures, exhaust ticking, maybe an air pump running.

I'm really glad I joined the forum now..I've been here less than a month and I've learned a lot. Now just to figure out what the noise is.

Do you still hear the noise with the radio turned all the way up? If not, then it's fixed.