Stingray odd flutter noise/hesitation on acceleration.. Please help
 

Hi Guys,

This will be my first time posting on this forum. I am the recent owner (2 months ago) of a 2015 C7 Corvette Stingray Z51 with only 12,000kms. I was very happy with the purchase as I work at a BMW dealership so I got a wicked deal and this car has every option you could possibly add, HOWEVER!

Since my ownership I've been having this problem that the dealership service techs just cant seem to fricken solve. Any time I am rolling (40-100kms lets say) and try to accelerate from low rpms I get an odd "Flutter or hesitation" with an odd sound coming out the exhaust until it kicks to the higher RPMS and it goes away. This is not normal as I have driven my friends C7's and other which definitely do not have this odd sound/feeling. It will also happen when heavy accelerating in the higher RPMS but never above 4500. It almost sounds like the engine or exhaust is dieing out and makes an odd "Fluttering sound".

I took it into the shop and it was first thought it was a Belt tensioner issue as this was a bulletin..... Still Happens after fix.... THEN after going back they diagnosed it as "TCC transmission shudder"....... STILL HAPPENS AFTER THAT....... THEN I come back and the other tech says "No, that's a PING". they clean my valves and tell me to put the HIGHEST GRADE of gas I can find (94 Octane here in Canada) and drive...... This is STILL HAPPENING. I have now phoned back to ask WTF IS GOING ON. They have now replied with "This is normal its called acceleration PING" or whatever. This happens in no other C7 I have driven so far so no guys..... it's not normal.

I am at my wits end with this fucking problem and I am hoping someone on this forum can shed some light before I pull all of my hair out. I love this car but I can't drive it and enjoy it with this annoying problem.

Probably related to one or more of the following:

1. AFM
2. Torque Converter
3. Exhaust valves

Your dealer should have info and/or TSBs on each of the above.

Thanks for your response. I've had it off the road and just put it back on and have done the following. I've had the TC torque Converter flushed and no change in the flutter/stutter sound. I've also had the exhaust valve replaced and no change.

Not sure where else to look any thoughts?

Sounds about like the same time/mileage my ‘15 starting experience the problem your having. It sounds like it might be time for a new torque converter. The GM TSB concerning the flush appears to be a bandaid fix IMO. Here’s a list (in order) of the items I’ve had replaced so far:

1 Torque Coverter
1 Transmission/TC Assemby
1 Valve Body Assemby
1 Valve Body Assembly Rebuild

Stay on ‘em. You’ll eventually get past your A8 issues.

So after MANY months of my original post I have tried the following:

1) New transmission/TCC flush as of 2019 spec. NO CHANGE (Tranny shifts awesome now tho)

2) Cut off exhaust flange/valve for possible fluttering of the exhaust valves, NO CHANGE

AT this time they are fully NEGLECTING it and saying there is not a problem and that it is "Pinging" (I run 91-94 octane ALWAYS) and say that it is normal operations.

It will flutter or even CLUNK sometimes on acceleration from cruise at 1200-2200 RPMS, this is becoming so annoying and is ruining my experience since I bought the car a year ago. Will I have to contact GM directly? If anyone has anything I could try PLEASE let me know.

Sounds like you service dept. has given up, and went to the usual "it's normal" route. I would try another dealer if there's one close, and definitely contact GM. No matter what your dealer says, that ain't normal. Good luck.

BTW, does the car act the same if you put the tranny in sport, and use the paddle shifter? That will keep the engine out of 4 cylinder mode. My previous '16 A8 did much better in 8 cylinder mode, so I bought a Range 4 cylinder disabler . It helped some with the clunking in the transmission.

I have the exact same thing and have narrowed it down to the AFM valves. This is my assumption of what’s happening. When cruising, and the engine is in V4 mode, if I would punch the gas the valves would open up but it doesn’t open fast enough and the extra climb of air from all 8 cylinders pushing through partially closed valves before they get a chance to fully open causes a flutter or whoosh noise.

I have the exact same problem. When the car is in v4 mode and I give the car light throttle the fluttering/wooshing/"soundslikeamousebeingsqueezedrepeatedly " sound shows up and grows progressively loader as I apply more light throttle. When I finally put too much load on the engine the car switches back into v8 mode and the sound goes away. I agree that it sounds like the valve is fluttering back and forth before it fully opens. No idea on how to fix this for cars out of warranty. Guessing AFM replacement.

Fixed the problem for me
 

I had the same problem. Mine occurred between 1300-1500 rpm and was usually in V4 mode. As soon as I pushed the gas it went away.

I changed the belt tensions pulley ($106.00) from the dealer and very easy to change. It fixed the problem on my 2016 and I also changed it out on my son-in-laws 2017 and it solved the problem in both cars and also the cars is running so much better now including response.

Update 2021:(
 

Hey guys,

well... it’s been awhile since I visited you all! It is now 2 years later and 5 different Chevy dealerships and they all say the same thing.

the engine is “pinging” constantly and this is apparently “normal operation”. Craziest thing I’ve ever seen and it happens 100% of the time when I’m driving and coming out of a cruising speed at around 1500-2500 RPMS and give it gas. I hear clunks and “fluttering” almost like it’s coming from the back of the car or a clunk under me but apparently this is “pinging”

I love the look of my Vette but it is time for me to move on my good people! I can no longer live with this car with a constant annoyance. I will miss you all and will be jumping over to the world of six cylinders and manual transmissions of Porsche!

it’s a sad day but I will probably never consider another GM product. Have a great day everyone.

2 years later...
 

Hey guys,

it is now two years later and I am back on the forum. It has been two long years and 5 different Chevy dealerships inspecting it.

every place has said the same thing that it is a “ping”. It is happening 100% of the time when I drive and it has become an annoyance that has me not enjoying any drive time in my vehicle what so ever...

I am sad to say I will be giving up on GM and my Corvette and saying goodbye to you all! I love the look of my car but I can just not stomach the constant irritation of this while driving any time I accelerate or try to enjoy it.

it sounds like a constant rattle or CLUNK from the middle or back of the car to me but apparently that’s “pinging” and everywhere has said that’s normal operation.....

I will be saying goodbye to GM and saying hello to the six cylinders and manual transmission world of Porsche !

have a good day y’all!

I had the same problem. Mine occurred between 1300-1500 rpm and was usually in V4 mode. As soon as I pushed the gas it went away.

I changed the belt tensions pulley ($106.00) from the dealer and very easy to change. It fixed the problem on my 2016 and I also changed it out on my son-in-laws 2017 and it solved the problem in both cars and also the cars is running so much better now including response.

Did you try changing the Belt tensioner? That worked for me. It's what I posted in my original repsonse.

The Hell with that troubled 4cylinder mod (AFM).You never reported if shifting to manuel and using paddle shifters help or not.
I would try to contact other owners in your area if they have a range device? Simply plug it in and try it.Or buy one here used if your trying to save a few bucks?
Great Cars when they are Right.

I don't why he didn't try a Ranger Device. Tis a simple fix.

Brace yourself when you start to shop Porsches, especially preowned. The prices of used Porsches are skyrocketing more than used corvettes.

Cold engine ping c7
 

HI - I have a 2017 C7, 5000 miles. Since new I notice a "ping" when I start engine from cold first time after few days idle. Im using COSTCO premium. Anyone else experience this. Is it normal when cold start?