Wondering what this could be? Alternator? Power steering? I dont think its PS becasue it turns fine the whine doesnt fluctuate with steering input.

Its just a very high pitched whine as soon as I start the car until I turn it off. Loud enough to hear at idle.

1992 RS 305 TBI.

 

Remove the belt & spin the pulleys by hand to feel any roughness or looseness.

 

Does the sound change with engine rpm or is it constant with no change in rpm? If its power steering, the noise will usually get louder when turning the wheel. If its alternator noise, it might change when you turn on the headlights or some other kind of load.

 

Most likely a belt issue, check that they are all tensioned properly, and not glazed or otherwise worn. If not that, its most likely the bearings in one of the accessories.

 

Could it be a vaccum leak? Buddy said it sounds more like air than a bearing. I have changed the stock air cleaner to an open element, but I plugged the one vaccum line to the thermac.

 

Did you ever get this resolved, as I am hearing the same thing on my '88 TA. A neighbor who has his own service business thought it was a belt bearing or the alternator (he did not actually see the car - just an educated guess).

Would like to know what you found out.

 

If you are only hearing the noise at idle, Especially with an open air filter, it is very likely air being drawn past the throttle blade and though the IAC. I hear it on my car since I installed ram air and the high flow air lid. The open passage from the front of the car to the throttle body transmits the sound much more than when there was the plastic and crud in the way. I don't mind the sound myself.

Another possible issue that I've run into on two different vehicles at the shop this year is excessive crankcase vacuum. These cars were both making so much CC vacuum at idle that air was actually being drawn through the front crank seal. It sounded like a dry bearing but it was coming from inside the front cover. I thought the first one might be a main bearing seizing up. In both cases, an overhaul of the PCV system(new valve, new filter) solved the problem. The diagnosis for it was simply pulling the PCV valve out of the valve cover. The noise goes away immediately, then takes just a second to come back after the valve is reinserted.

 

Thanks for the reply. In my case I hear the noise pretty much all the time, and it increases as the engine it revved. My air filter is stock, and this inside the housing.

I will check the PCV just to be sure.

 

Be sure to try removing the accessory belt and running the motor to see if it might be an accessory drive noise. You don't say what year your car is. Is it a serpentine drive car?(single multi rib belt)

 

1988 Trans Am with TPI, thus only a serpentine belt. I should probably remove the belt and check pulleys plus have alternator tested.

 

Oh yes. I didn't read thoroughly enough. Removing the belt will isolate the noise to the accessory drive. Then you can use a stethiscope to further pinpoint. The aluminum accessory brackets transfer noise very effectively, making it difficult at times to differentiate between engine and accessory drive, or even between different accessories. But the belt off test helps eliminate a possible engine problem. Bench testing the alternator sounds like a good way to go too, once you you have it narrowed down.

I remember a Ford Explorer with the 4.0 SOHC engine. The dealer who had sold it my customer(without him first having it inspected by me or another professional), had replaced the accessory belt and the tensioner in an effort to quiet a grinding noise in the front of the engine. I removed the belt and verified that the noise was in fact an internal engine problem. The customer then paid me for the 16 hour job of replacing the timing chains and tensioners, front and rear, on a car he had just bought. All because he hadn't had the car checked out before signing the contract. Takes a few minutes to remove and replace the belt and it would have saved him $1,000s.

 

It is a common noise of TBI set ups when the base gasket drys out and starts to leak. This is the gasket between the TBI unit and the intake manifold. Although, I've thought of it more of a whistle then a whine.

Note that it is common for this to occur. Replacing the base gasket is quick and easy, even on the wallet.

RBob.

 

Yes I would change that gasket first.

 

Good to know. I will check that out. Thanks.

 

Just a quick question. Is this gasket readily available at your typical autoparts store, or is it less common and may need to be ordered?

Thanks.

 

Probably 50/50 on that, give them a call.

 

The Rochester Dual Jet TBI was used on so many engines, in trucks, SUVs, and sedans throughout the late 80s to mid 90s that the TB base gaskets are everywhere. I install 2 or 3 a year and they are in stock at NAPA and Car Quest for sure, probably every other store as well.

 

What would be the actual name of this gasket? I may need one

 

These guys are still talking about TBI base gaskets. Not TPI or MPFI.
Not sure if such a gasket would help you guys.

 

Compressor bearing?