Took my C63S final edition to Mercedes for a CEL, they said there was a fuel pump recall and replaced it, and they updated the software (including ECU).

I just picked my car up from them and the pops and bangs are completely gone and car feels sluggish.

When I called them they said the pops and bangs would come back after a couple days of driving and if not to take it in and they’ll tune it for pops and bangs.

Also, when I go full throttle now the car doesn’t launch as aggressively.

Has this happened to anyone else?

 

If the FE had the same pops and bangs as the pre facelift car which many claim it does then unfortunately I think you been had.... Happened to many of us, and there's a few topics here about the ecu update. You won't get the pops and bangs back and I doubt Mercedes will tune them back in. I think they tune the car for reliability and warranty purposes to save themselves cost on the long run. Only way is to go for an aftermarket tune now.

 

Yes I’ve heard the pops and bangs on the FE are similar to the pre facelift.

I’m afraid that might be the case. I’ll wait a few days and if the pops don’t come back I’ll take it back and see if they can tune it since they offered that.

What about the car feeling slower, have you heard of that? I’m thinking the car’s ECU might have to learn how I drive all over again and that might be it?

 

I've had a few ECU updates with my FL, but it never was sluggish afterwards. Updates do seem to reset some adaptations, though. The shifting is at first a bit softer and adapts again over time. However, I drive 90% or more in manual mode. Is it sluggish to downshift when you are getting on it, or is the throttle response sluggish? Is it still sluggish if you put it in manual mode and ensure you are in the right gear? Does the boost gauge show full boost? Also if you bring up the engine data in COMAND, does it show a reduced horsepower and torque scale? The latter would indicate limp mode. I could understand if replacing a fuel pump may require the ECU do recalibrate before it opens up fully again.

 

This hasn’t been 100% confirmed. I’m assuming you have a Euro-spec FE? The Euro FE press car did sound a lot like the PFL. However, I haven’t seen a USA FE owner confirm that their car sounds similar to the PFL. From personal experience, I do think the non-FE ‘23’s have more pops and bangs than 2019-2021 FL’s, but they’re still not at the level of PFL’s.

Sadly, I don’t think the dealer will bring them back once they’re tuned out. At least this was the case with PFL’s. It’s been discussed by several pissed off PFL owners how they lost their pops and bangs after a dealer ecu update.

 

How many miles have you driven it since they updated the car now? Give it at least 50 miles to relearn

 

I've driven it for short distances a couple times since I posted this and it seems the car is driving like it used to now. I heard a few pops and bangs now (which were non existent when I first picked it up) but they're still much less than before the update. The dealership told me to drive it 50 miles then leave it overnight, and the pops should come back.

 

I've driven it a couple times since I posted this and it seems like its back to normal.

 

Yeah it takes a while after an update but it'll come back in full, glad to hear it's good again. Are you going to get the next software update? Or has this worried you a bit

 

I'm not sure to be honest, the pops and bangs did come back but they are way quieter. MB service center told me they are working on a solution still, but I've lost hope tbh. Will update my post if they do fix it.

 

Update: MB weren't able to reverse the update and the crackles haven't come back like they used to be. They said that this update was done in order to make the car more efficient and reliable. Not happy about this, have some downpipes on the way so it won't matter much in the end.