Lost 80-90% of the bangs/pops/cracks/snorts when you lift your foot off gas after acceleration in Dynamic mode.
Used to have intoxicating sounds since owned in Mar of this year until the weekend, when I discovered this change. Earlier that week, I had sent the car for a detail (included polishing the exhaust tips) and I discovered the change on my first drive after the detail shop delivered the car to my place. Took the car to the dealer: dealer said everything looks OK (Active Exhaust, exhaust flaps open and close as they should). Dealer asked if I had change the gas I used to fill in, which I did not. Detail shop denies putting in gas (driven too little for that). I am not aware of any software update to the car. Very frustrating. Appreciate any help you could provide about potential cause and fixes, and thank you in advance.
2018 F type R AWD.

 

Hi, I cant help but I did have a similar experience late in '23, all of the sudden my car sounded quieter, like a turbo, and it drove me mental. Jag denied fiddling with the tune, my other mechanics checked it and said everything was functioning fine, I was beside myself because apparently if the ECU is changed you cant go back without risking disaster, anyway this went on for about 4 months or so and then one day I realised it was back to normal and it has been fine ever since. Someone suggested maybe blockage in the cats?

My thread about it will be in here someone, probs late '23. The panic was palpable...

 

Thank you Bruce for sharing your experience. while I dig in your so many posts (you are a prolific poster!), did you by any chance change the battery during this 4 months hiatus? trying to think if low voltage could've been the culprit and if changing the battery could help me....

 

Funny you mention that, I had issues with a few things with the car last year coming into this year and one involved the rear battery and it was replaced as part of that, about the same time as I had cone filters installed, and from memory it was some time after that installation that I realised my sound issues were solved. It was like when you have a sore back and it nags at you for ages then one day you realise it has gone.

 

I have opposite problem with my 2024 R…I quite liked the sound when new, with the occasional crack pop and and bang thrown in…These days there seems to be a lot more burble tune, cracks, bangs etc. than I remember…Seems to be increasing.

It’s not to the level where it’s bothering me necessarily, but I really do prefer less of that kinda thing…Less is more ;-o

Anyone else notice that as their car has broken in?

 

Were the detailers polishing your exhaust? ;-0

In all seriousness, despite my post immediately above, I have noticed quite a bit of variability in the loudness of my exhaust as the car has broken in…At least it seemed that way…Perhaps it’s just my old ears working better some times than others. Some times it did not feel as loud. It was notable. Not sure if you are experiencing some similar variability, and it will just sort itself out.

I mean, at least you know that for your conditions there was no possible way the software was changed. It clearly needs to be something else.

 

Yes, we discussed that here years ago. These cars do seem to get louder in their first thousand miles.

 

Okay, interesting…Didn’t see that discussion during my travels here, so thanks. Yeah, in my case it seemed to take more than a 1000 miles before I saw a notable change.

 

Thanks for everyone who chimed. To be specific, it is quality of the sound, and not loudness, what changed for me. The snaps/cracks/bangs are gone. They used to come on demand when I lift my foot off the gas pedal. If this is a software driven functionality and I have not done a software update, I am thinking along the line of battery, O2sensor, and catalytic converter for troubleshooting.

 

lol. Reason I mentioned polishing the exhaust tips is it crossed my mind that goo from polishing compound and/or dirt could have seized the valves. However dealer said valves are working ok. Makes me think something electrical and not mechanical.

 

I tried to infer your location. Wild guess but could this somehow be related?

 

Hmmm! learned something new.... I guess this could be related. Maybe I'll try to add a bottle or two of fuel additives/octane and see what happens. Thanks for sharing.

 

Sharing an update. Dealer now wants to start trouble shooting by looking at vacuum lines originating at the engine.

 

I believe your model year uses engine vacuum to actuate the active exhaust valves. (Mine has an electric vacuum pump.)

 

Anyone could share how valves actuation is related to the cracks, snaps, and pops? I can understand how valves would change the tone/make the exhaust more throaty but can't wrap my head around how valves would create cracks and pops...

 

The cracks, snaps and pops are generated by unburnt fuel exploding in the exhaust pipes and have nothing to do with the operation of the exhaust valves.
Controlled explosions governed by ECU programming which is how/why later models and ECU updates applied to earlier models tamed the fun somewhat.

 

Hopefully this doesn’t end up being an expensive wild goose chase. Can happen very fast at these dealer. They love to take yer money ;-o

I can’t imagine that it has anything to do with it. Isn’t that just more to do with whether the valves will open and close?

Perhaps I’m missing something here.

I would definitely rule out it being gas/octane related etc before spending any money on the problem.

 

@OzXFR is correct. Exhaust noise on deceleration happens in the tune.

I tuned modern EMSs for about a dozen years, gave it up a couple of years ago. Using hack SW, I could access the various tables that the Engine Management System uses to manage Air/Fuel/Ignition.

This is a VERY large explanation VERY abbreviated.

In the fueling aspect of engine management, there is a component when you release the throttle pedal called Deceleration, Fuel Cutoff (DFCO). Via DFCO (and with numerous parameters) you can control the fuel AND the ignition AFTER throttle (air cutoff) is released, or closed. It is through these parameters that sounds on deceleration can vary, from nothing to very loud.

Many mfgrs that first introduced models that had lots of cracks and pops, and BC of very many EPAs around the world tightened up noise and emissions controls, upgraded their SW to eliminate the latent fuel and spark after throttle cutoff. So, some owners of cars that brought them in for servicing, had the tune upgraded (some with and some without their knowledge, but mandated SW upgrade). On later models of the same car, the newer SW from mandates was already installed. I played a lot in the world of the AMG GT and this is a classic example of the above.

With very light explanation, here is an example of what the page looks like in a tune where air/fuel/ignition can be manipulated on DECELERATION.



BTW, if I had access to the hack SW needed to get into any tune, I can make the sounds appear in about ten minutes of tune manipulation.

 

DMeister - this is interesting. If you don’t mind, at what mileage did you notice the increase in cracks, bangs etc? In KM please. Miles hurt my Canadian brain!

Thanks.

 

I recall noticing it pretty much right at the official broken in KM mark…So, 3000 km or so…That’s my recollection.

How many KM do you have on your car?