Anyone else????

 

I can easily hear it when you snap the throttle; what happens when you very gradually and smoothly bring the throttle up off idle?

 

sounds normal to me, engine sucking air.

 

Mine sounds the same since day one. 62K daily driving miles.

 

 

Still happens but less exaggerated.

 

FWIW: OP, know you said you don’t want to mess with it but - - as I expected, the dealer will be of little help! “It’s Normal,” is what you’re told when they will get nothing from GM for diagnosing then finding a leak near a fitting, etc.!

Read my post #10. I would take off the black duct going to the hood vent, just a few bolts, but if you are not handy try the following without doing that:

Get a 3 foot section of old garden hose. Don’t have one? Go to Lowe’s and buy a piece of 3/4 clear hose (it comes on reels, they will cut to size.)

Have someone in the driver’s seat.

Put one end of the hose next to your ear.

Than start at the throttle body rubber connector and clamps, put the other hose end around that area. I would put top, bottom and both side. Have the person in the driver’s seat gun the engine to create the sound.

See if the noise gets louder. Assuming NOT. Move to the two hoses mentioned in post #10. They are connected to the black plastic appendage attached to the intake air tube. Look under the plastic hood vent air duct. Again gun the motor to create the sound. Follow those hose ends to where they start, one at the engine and the dry sump tank. Check there as well.

Assuming it does not get louder, move to the electrical fitting on the air intake tube near the air filter. It has a red locking clip and it is toward the engine. It’s the only wire attached. That is the MAF sensor. Check there for increased noise, i.e. a leak from the hole where it inserts.

Then, if NOT, check around the air filter housing where it parts. Check along the top bottom and sides. If NOT, as the dealer said, “It’s Probably Normal,” but frankly from what I heard on the video - - NOT! However can’t think of any other easy way to isolate at this time so live with it!

Kidding, when you do find out what it is, let us know.

PS: By the way if you have more than ~25,000 miles and have not done it-change the air filter! That will require removing all the connections I mentioned above, and the intake air tube.

If you did change the filter yourself, or worse paid to have someone do it, that could be the source of the noise! My rule since messing with cars for 60 years is “always look at the last thing you touched!” Often something not tight etc., etc.

If a dealer changed the filter they did not connect something correctly. The rubber sleeve and clamps at the throttle body would be the first thing to check!

That high pitched noise, IMO is caused by air traveling at the speed of sound leaking through a small hole. Much like a musical instrument! I have an Ultrasonic Leak Detector used to check indusrial gas or compressed air leaks from pipeline connections, etc. It amplifies the sound and for frequencies above audible, lowers that frequency so they can be heard though ear phones attached to the unit. Can hear from 10 to 20 feet away. As you get closer it gets louder. However the hose approach should work in your case.

 

My 1LT Stingray does this. I think it is normal.

 

This implies to me that:

a.) it's coming from the throttle body area, and
b.) it may really drop into the range of "normal"

Jerry's procedure is a good one, try it out. I'm confident you won't do anything to screw up your warranty, and you will definitely learn more about your engine.

HTH, and have a good one,
Mike

 

I noticed this in my 17 gs when I bought it new. It has something to do with throttle application length. If you blip the throttle very fast you will hear that noise. If you are out of the pedal before the throttle body has adjusted to your initial throttle input it will make that noise. I have just passively learned to drive around it honestly as I never hear it anymore after driving it a whole season.

My c5 engine spun up much faster being a built motor with a light clutch that was tuned with the throttle setup to be much more direct. I recall being sure when I putzed with this it was a function of the throttle lag inherent in the stock c7 system. Which means its possible it may change with driving modes, but once I trusted the car wouldn't die when the revs dropped below 900 rpm, which I was conditioned to with my c5, I really don't have a reason to apply throttle in that manner anymore.

 

It s normal. You better go for a Prius.

 

It didn't make that noise for 2 years so I don't think it's normal. Jerry, the last thing I touched was I installed a mild to wild switch. I was running with the fuse removed. I unplugged the plug to the fuse box and returned it to stock and had the same noise. The only thing that was still connected from the MTW was the ground wire which was a little difficult to reach. I think I will start at the ground connection and see if I disrupted somethings installing it. Thanks for your imput. Hey Walley I am 71 years old and have been playing with performance cars since I was 14. I think I know a foreign sound in my cars. Did you ever think there was something wrong with your car too? I will get the car out as soon as the snow melts and let you all know if I find anything.

 

I was just gearing you B stock. You have an extra 4 yrs on me. Good luck, snowed in here also.

 

I just listened to your video. I have a 2016 Z51 Mn7 and now have 13,000 miles and I have NEVER heard that noise. Find another dealer.

 

I just noticed you are in Rhode Island. I now live in Florida but when I lived in S.E. Connecticut, on the Rhode Island boarder, I used M.J. Sullivan Chevrolet in New London, CT for service and they were great. I have been gone for almost 9 years but they always took great care of me....of course I purchased my Corvettes from them.
Good luck!

 

Don't see how actuation of the exhaust butterflies can do that -but guess it's possible.

 

Were you able to figure out what it was?

 

Nope

 

I am so sorry about that! So dealership just never fixed it?

I just bought a certified pre owned 2018 stingray and have the exact problem show up 3 days after I got it. I have an appointment today. Will keep you updated

 

Unlike my prior 2017 thought of a small hole, believe it is probably part of the sound (compounded perhaps with the Helmholtz device in the intake) as the throttle body goes from almost closed to open. It's a complex transient flow as the throttle is increased from idle. This old PDF of the modified Throttle Body I installed on my Grand Sport may give some insight!
Soler_Mod_TB.pdf (netwelding.com)