Need help with CT5V BW vibration

[Slick Blackwings]

So, as some of you might know, we’ve got 2024 six speed has a vibration on deceleration highway speed 80 2000+ RPMs brought it to the dealer pico scope sent to GM Of course they say everything is normal in my opinion it’s not. If there’s anyway I could get a ride with somebody in their car in Northern New Jersey, northern PA lower Hudson Valley. Don’t want to put anybody out. I’d make arrangements whatever time works for you. Any help greatly appreciated. I really just want to find out if this is actually normal for a manual car. Thanks in advance.
Richard

 

[GTANotch88]

I'm in that area but my car is away for the winter. Probably until April at least, but if you are still interested after then, I'm sure we could figure something out.

 

[Jim2000]

So, as some of you might know, we’ve got 2024 six speed has a vibration on deceleration highway speed 80 2000+ RPMs brought it to the dealer pico scope sent to GM Of course they say everything is normal in my opinion it’s not. If there’s anyway I could get a ride with somebody in their car in Northern New Jersey, northern PA lower Hudson Valley. Don’t want to put anybody out. I’d make arrangements whatever time works for you. Any help greatly appreciated. I really just want to find out if this is actually normal for a manual car. Thanks in advance.
Richard

Does it vibrate when you only apply the brakes?

 

[Slick Blackwings]

Does it vibrate when you only apply the brakes?

No brake application, simply engine deceleration

 

[Slick Blackwings]

I'm in that area but my car is away for the winter. Probably until April at least, but if you are still interested after then, I'm sure we could figure something out.

If nobody else comes forward between now and then that would be great . Drove our A10 today silky smooth!

 

[fragment]

I noticed a vibration that felt like trans or diff in my 5BW 6Speed during steady state cruising at about 120 km/h in sixth gear. At first I thought it might have been "washboard" or texture on the road. I tried accel / decel and it didn't change much. I was able to reproduce the vibration in town the next day in 2nd gear above 2k RPM. Booked it into service and they've had it for over a week now with no diagnosis. The service writer told me they did experience the vibration but it comes and goes. They've pico'd it and are working with factory level support. He did say the factory is taking it seriously so I'm hopeful.

Maybe related or not but I threw a CEL before this vibration occured so I wondered if it was a bad misfire. The dealer said that wasn't the problem.

BTW, anyone else not happy with the location of the CEL light? With my driving position, its exactly behind the rim of the steering wheel and I honestly don't know how long the light was on.

 

[fragment]

Update on mine. Just got a text from the dealer saying "diag on your car has been escalated to the engineering dept now as the tech assistance line was unsure how to proceed". Hmmm

 

[Jim2000]

Update on mine. Just got a text from the dealer saying "diag on your car has been escalated to the engineering dept now as the tech assistance line was unsure how to proceed". Hmmm

Sounds like bs from the dealer.

 

[Dougyfd]

Does it vibrate when you only apply the brakes?

He never mentioned that it happens when braking. These cars aren't known for having defective or out of round rotors. Only your old ats v had that problem it seems

 

[BrakeFade]

I’m thinking driveshaft.

 

[Jim2000]

He never mentioned that it happens when braking. These cars aren't known for having defective or out of round rotors. Only your old ats v had that problem it seems

Leaving brake pad deposits on the rotors caused the vibrations. Why were these brembo pads so inclined to do this?

 

[BimmerFan]

I don't know what "pico" is.

My 2023 6-speed, while deaccelerating in 6th at highway speeds (but only in 6th) makes a weird noise, kind of like a Jake Brake on a semi, although not nearly as loud. To me it sounds like the car has shut off the injectors and it's just sucking in air while my foot is off the gas. It's always done that, it's very consistent, but I've never seen anyone else here mention it. I wonder if it's the same thing, just described differently?

Leaving brake pad deposits on the rotors caused the vibrations. Why were these brembo pads so inclined to do this?

Any high performance brake pad will do this. They're designed to perform well on the track, and most people on the street brake too lightly and for too long and leave behind material. A few runs with heavy braking will usually clean them off.

 

[Jim2000]

I don't know what "pico" is.

My 2023 6-speed, while deaccelerating in 6th at highway speeds (but only in 6th) makes a weird noise, kind of like a Jake Brake on a semi, although not nearly as loud. To me it sounds like the car has shut off the injectors and it's just sucking in air while my foot is off the gas. It's always done that, it's very consistent, but I've never seen anyone else here mention it. I wonder if it's the same thing, just described differently?



Any high performance brake pad will do this. They're designed to perform well on the track, and most people on the street brake too lightly and for too long and leave behind material. A few runs with heavy braking will usually clean them off.

I don't agree. With my other performance cars with Brembos, I never had that problem. A few runs with heavy braking did absolutely nothing in regards to the vibration. What worked was having the rotors resurfaced and after some time, the vibration reoccurred.

 

[rubberduck]

I don't know what "pico" is.

My 2023 6-speed, while deaccelerating in 6th at highway speeds (but only in 6th) makes a weird noise, kind of like a Jake Brake on a semi, although not nearly as loud. To me it sounds like the car has shut off the injectors and it's just sucking in air while my foot is off the gas. It's always done that, it's very consistent, but I've never seen anyone else here mention it. I wonder if it's the same thing, just described differently?

I haven’t heard that noise, what RPM are you at? But my driving style is to downshift if I’m decelerating. And if I’m in 6th to begin with I’m around 100mph. Mostly I try to keep it around 90mph except for brief bursts.

 

[Slick Blackwings]

We have the same issue, 6/5 gear decelerating from 85 to 70 not heard above or below those speeds weird noise vibration not crazy but there. I did mention this back in January, dealer says all good our A10 doesn’t have the issue!

 

[Barstoolman1127]

 

[BimmerFan]

I haven’t heard that noise, what RPM are you at? But my driving style is to downshift if I’m decelerating. And if I’m in 6th to begin with I’m around 100mph. Mostly I try to keep it around 90mph except for brief bursts.

90 MPH, LOL.

2K RPM, perhaps? 70 MPH or less, in traffic, I don't need to be in a lower gear, I'm not going anywhere...

 

[rubberduck]

90 MPH, LOL.

2K RPM, perhaps? 70 MPH or less, in traffic, I don't need to be in a lower gear, I'm not going anywhere...

when I’m just cruising highway or city I don’t get below 2500rpm ever. Just my style and what I used to. I don’t like to have to downshift 2 gears to make an impromptu move.

 

[DCV]

Same here. I like to stay at 3K most of the time to keep the turbos spooled up, and only use 6th gear when I’m above 100.

 

[fragment]

Official diagnosis from the dealer is "bad gas" :ollseyes::

The CEL was a cat efficiency code. No misfires. Hmmm. Explain how "bad gas" doesn't throw misfires or knock codes, doesn't plug the fuel filter(s) but manages to make the drive train vibrate? Service writer couldn't. But they say its all good now since it was filled with fresh gas, so let's just monitor.

I feel like a prom queen who's BF is saying "you can't get pregnant the first time".