Hi all,

I've read through as many previous posts on this topic as I could've but didn't find anything that was applicable to my situation.
A couple days ago on my weekend drive, I popped the car into Sport+ as I usually do, but this time the pops and crackles while letting off the throttle disappeared. I've since tried it after leaving the car for a bit, it didn't change.

I know I haven't gotten any service done so an ECU update doesn't make sense, the pops were definitely there after the last one. I also made sure the engine and transmission temperatures were up to operating conditions. I've also consistently gotten gas at Costco (91 octane), so a bad batch or bad gas station doesn't make sense. There also haven't been any lights on the dash.

Looking for any other explanations for what can cause this, and any fixes to try.

Thank you!

 

Scan for codes - not all codes generate a CEL as you know

 

Are your exhaust flaps staying closed?

 

No, the exhaust definitely gets louder when in Sport+, it's just the pops/bangs on throttle lift off that disappeared. So seems like an ECU-related thing, just can't figure out what it is.

 

I don't have a scanner, which is why I was looking for suggestions I could try before having to take it in a shop.
On a side note, do you have any recommendations for an inexpensive but effective scanner that I could buy?

 

I don't have a scanner, which is why I was looking for suggestions I could try before having to take it in a shop.
On a side note, do you have any recommendations for an inexpensive but effective scanner that I could buy?

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Yes scan the vehicle, a soft code can disable the pops and cracks, any scanner will do to be honest, forum members recommend Launch CReader Elite Benz V2.0 however you could probably just get something cheap instead if you don't need a proper scanner with Bidirectional functions.

 

Here is the scanner that might work, https://mbworld.org/forums/c450-c43-...ml#post8562347

 

Thank you, really appreciate it!
Possible dumb question - If it is a code that's minor enough to not trigger CEL, do I just clear it using the OBD scanner? Or does it need to be taken to a shop/have some work done in order to clear the code? What happens if I clear it without having anything done?

 

Depends on what code is stored, let us know what code is displayed then go from there.

 

So I got the scanner delivered and checked it out, it didn't show any stored or pending codes. :/

 

Try the “powerful” exhaust button. The car will get louder in S+ through changes in the ECU not just the flaps. So if you have the AMG Performance exhaust and the flaps don’t open you will see no change in exhaust while in Comfort Mode and Powerful exhaust settings.

 

Sorry to hear that OP, try what is suggested by the other forum member first.

 

I don't have the AMG performance exhaust, which is why the exhaust volume and pops/burbles are just controlled by toggling into Sport+.
Might try a different gas station once I deplete the tank and see if that does anything. Otherwise unsure what else it could be. I wonder if the outdoor temperature/humidity could effect this even though the engine/trans temps are at operating conditions.

 

It shouldn't completely be gone though, strange, other than soft code I really don't see how it will cause it, the reason why all pops and bangs and burbles are gone when a code is stored, is because the ECU deemed it unsafe to protect the engine. As you know, the way it is produced is the ECU retarding timing and dumping unburned fuel in the exhaust, so if the ECU is not certain it is safe, it won't do it.

I am sorry the scanner didn't find anything, although I do hope there are no codes stored with the vehicle for your sake (meaning vehicle is functioning properly), it could be the scanner I linked you is not compatible with the W213, it was compatible with the W205 C-Class from the other thread, you could try getting that Launch CReader scanner instead or go to AutoZone and have it scanned, hopefully you figure it out soon as I hate to hear that you can't enjoy the car.

 

If you still want to try a different scanner, here is the link, if you need it: https://mbworld.org/forums/e-class-w...ml#post9080013

 

Sorry this is the right link: https://mbworld.org/forums/e-class-w...ml#post9073190

 

Just an update: got a fresh tank of gas and tried it again on the way home, and pops are back. Gas was again from Costco, so I have no idea what could've caused this earlier. Will be a mystery what minor things can throw off the ECU

 

Old gas... winterized gas ...changes octane a bit no two tanks of gas are necessarily identical... engine ecu retards timing and less extra fuel left for the hot catalytic converter to ignite for those pops and crackles everyone loves so much

it's why we put fuel stabilizer in our gas tanks for the lawn/snow equipment

a simple way to not have to go through a whole tank of fuel if this happens again is add a gallon or 2 of e85 or 100 octane race fuel into your mostly full tank of 91 or 93 octane to ramp up the octane and see if after a few miles the engine learns the higher octane and brings back the fireworks

 

Ya that could be it,

 

i had this recently. no pops and bangs on a trip or the return, 20 minutes each way. returned on the next start up. who knows