New Caprice - Discussion forums

Picked up my 2014 new a month ago, had 200 some miles on it. Now it has just over 1000, love the car! Now, this is my first car with DOD/AFM but I don't think you should be able to tell the difference with it on or off.

Going about 60-75MPH down the highway there is a rumble (drone), almost like a wheel bearing gone bad, I realize that this is the AFM working. I go to deactivate the AFM by giving it a little more throttle, noise goes right away. Its to the point where I feel it in the floor and the rear view mirror is vibrating. Car performs well, no lights, no noises (other than whats stated above).

Normal...or????

Yes, that sounds about right. Sounds a "little" on the noisy side, but typical. There area few ways to get rid of the AFM. Tuning it out is possible (least expensive) or doing a cam/lifter DOD delete (most expensive). Any changes in the stock exhaust system could make the sound more noticeable. The stock system is very restrictive, but does a good job tuning the 4 cylinder sound out.

Regards,

Maurice

Heavens no, this doesn't sound normal. I drove my 2014 from Illinois to Florida and for practically two days it was running on 4 cylinders without a groan, chug, click, or any noise at all. Was even more seamless than my C7 Stingray.

Yea this does seem a little excessive, if I were a customer with little/no mechanical knowledge/experience, I would definitely say something about this noise. But I didn't know if it was normal or not for these cars.

If you're still under factory warranty, dealer-ize the problem. Make them tell you it's normal, that way if something goes south later you've both documented the concern and your attempt to have it corrected through the warranty maintenance channels. Just sayin....

Eric

Oh yea of course, im taking it in this week to replace the headlights. They already don't like me, they say im "Knit picking" *headlights obviously deteriorating, I complain, they shoo me out the door*

So I did a little bit of research, found out about a TSB on the shuddering/vibration during AFM 4cyl activation that listed the L77. The tsb was dated 2015

Apparently, the torque converter clutch regulator valve spring breaks and causes the torque converter slip drop to zero when it isn't supposed to, causing the shudder.
Fix is a new lower valve body.

Car is currently at the dealer (and has been for the past week and 1/2) and according to GM, this is a normal issue because its a harsh/severe duty vehicle....I call b/s. Called GM and now my dealer is blowing my phone up...lets see what happens, ill keep you guys posted.

Update number 2....after a very terrible experience with my original dealer, I chose to go to another dealer. These guys actually looked at the car and attempted a diagnosis. They took the car and used a "vibrometer" (used to check NVH, Noise/vibration/harshness) to measure the nvh percentage. My car during 4cyl mode registered at 2.8%, they also tested another 2014 caprice and it was around 7%. They told me GM's limit is 7%, so the car is within spec and there's nothing they can do.

On that note, looks as if im going to get rid of AFM/DOD, because that's when the vibration occurs. BUT, I also did notice that my car has a 6year 100k mile warranty, I was under the impression it only had a 5yr/50k. So im kinda on the fence on doing the delete now or just wait.

Do it now. The only way to repair it correctly after you've had failure is to tear the engine down completely so it can be cleaned properly. Dealers don't do that.