A few weeks ago, I was doing some work under the hood, and removed the alternator for additional work room. Naturally, I had to disconnect the battery. When I was done, and got everything back together, and started the car up, for about 10 seconds the car sounded like it had a "smokers cough". I don't know how else to describe the sound. I thought that for some strange reason, being "powered down" for a couple of hours did something to the car.

By the time I got out of the car, and the hood back up, the noise stopped, so I couldn't try to trace it down. It did, however, almost sound like a funky A/C compressor. All was OK until two days ago. I drove the car to a church function, where it sat in the sun (if that matters) for 3-4 hours. I started the car up, it sounded strange again, for a moment, then it let out a chirp for a couple of seconds, followed by a short "pf-f-f-t" sound, like air being let out of a tire, then all the noises stopped. I dumped the clutch, blipped the throttle, and everything sounded OK, so I drove home, about 2 miles.

Yesterday, I popped the hood and started the car, and everything seemed normal. I looked at the balancer, and it appears to be OK, although it may have a little more runout than normal. I can't be sure however, as it seems to change, depending on my angle of vision. It might be some staining on the balancer, creating an optical illusion.

However, I'm not worried about the balancer, as I was planning on replacing it anyway, and I've been acquiring the special tools I need for that job, and just ordered an ATI balancer today. What really concerns me is the strange noises. I checked for codes about an hour ago, and there are none. Has anybody else experienced anything like this?

I have a chance to go on a "cruise" around the Watkins Glen race track in a couple of weeks, and this unknown issue has me bummed.....

TIA!!

 

A year ago, or so, I noticed an unusual noise/sound upon initial start-up that receded and quit after a couple minutes. Kind of a muffled "roar" sound for lack of a better word. Over time it was progressively getting more noticeable. No codes.

After further investigation, I determined it was the A.I.R. pump going on me. It's basically an electrically driven air pump and the bearing/bushings were getting louder as time wore on. As it primarily operates during "open loop" (translation: engine is cold) and shuts down during "closed loop" status, that explained why I wasn't hearing it all the time. "Warm" start-up was fine. Easy fix and all was well.

Not saying this is your particular problem, and certainly mine wasn't exhibiting the "smokers cough" you describe (), but just putting it out there as food for thought. FWIW, you might give the eyeball to your entire A.I.R. system, i.e. check valves, gaskets/hoses, etc.

HTH

Btw, the pump is year model specific, so if you DO ever replace it, get the correct design for your year.

 

"Lone Star", thanks for the info. I'll look into it!

 

Yea but u havent told us why u removed the Alt for room to do something else. What did you do to it? Might be helpful

 

I took the valve cover off, and one of the coil pack bolts is easier to get at with the alternator swung out of the way....

 

Thats some strange Symptoms. UR Gone-a have to have some one around when u start this thing so u can pop the hood and start video taping ur start ups so when it acts up you can post the videos here for us to hear.
Only way dude ur going to get this solved. Sorry ur descriptions anit going to help a wrench fix anything but from what u said its seems you did something because this started after you strated taking things apart and not before
Post some start up videos. We'll take it from there

 

A.I.R. system was also my first thought, but hunt around your engine bay for vacuum leaks before you do anything else. Sometimes tiny leaks will whistle or "chirp" as you described, and they can be sporadic as well ... a cracked hose shifting around when you blip the throttle for example.

 

Fortunately, the car isn't my DD, so I can let it sit until I have a little time to look at it. Since it only makes the noise sporadically, beginning recently, and at start up, I think you guys are on to something, with respect to the A.I.R system.

I'll be looking into it on Wednesday afternoon, when I get home from work, as Wednesday is a "short day" for me....

 

OK, it's Wednesday evening..... I pulled the A.I.R. pump this afternoon, when I got home from work. You can't tell anything from looking at it, so I disassembled as much as I could, and took the compressed air to it. A LOT of dust, I'm assuming from the motor's brushes, came out. I was able to get a drop of oil on one end of the motor's shaft, but the other end is buried under the fan blade wheel, which is pressed in place.

I put everything back together and fired up the car, and there were no strange noises. I guess time will tell, but thanks again for the suggestion.

One thing I did notice, when looking at replacement pumps, is the great disparity in pricing. AC Delco pumps are VERY expensive, but they are a complete assembly, including all of the plastic ducting, housing, etc. Dorman makes a replacement motor, without all the other parts, which you then transfer from your old pump, for about 1/5 the price.

 

It's been a week, and no unusual noises. I'm keeping my fingers crossed....

 

I spent time shopping and had similar experiences. I discovered frightening examples that were advertised or priced somewhere between excellent to fair condition, but were in poor condition. I test drove examples that, quite frankly, I feel placed my life at risk by the dealer handing me the keys and allowing it on the road.

After getting in these cars and driving them, I felt they were priced for a sucker who was simply excited about getting a Vette, or priced by someone who wanted to cash in on their losses. I'm sorry for your experience - I'm sure there was some glimmer of hope after you choose to spend your time to look at that car.

Keep looking - you'll find one that sits right with you.