[coldM2]

Hi everyone. I'm new to this forum so I'm not sure if I found the right place to post this.

currently waiting for an appointment to get my car troubleshooted so I'd just like to see if anyone has had these problems or if theres an expert here that could possibly know the reason for my issues.

I've just got a 2016 BMW 340 with the mppsk package, and I absolutely LOVE it. I've had it for 6 weeks now but it wasn't untill last week I noticed a big change in the cars behaviour. So there's a couple of things I noticed that just wasn't the same as in the first week of my ownership and I'll list them here:

1: Strange behaviour during startup(doesn't mather if its a cold start in the morning or when im starting it up after I've driven for a while, it sounds the same). It was one morning when I was leaving for work that I noticed something very strange in my startup. As many mppsk owners know the coldstart provide a pretty loud idle sound that lasts about 30 seconds. What i noticed one morning was that there was no loud idle sound at all but the car would go into quiet mode instantly and has been like this for a week now. Everytime I start the car it sounds like this even if I for example pull up to the store to grab something quickly it just has a weird startup. I will try to provide 2 videos showing this but the videos do not justify the sound due to the poor iPhone 6s. Will try to re-record.

2: Delay in downshifts Ive noticed a very small delay in my downshifts while riding in whatever mode. This is hard to explain but any driver would notice this especially when it was quick and precise the previous 5 weeks.

3: No pops or bangs in downshifts Another issue is that I hear no pops or bangs while downshifting in sportmode anymore, the motor just leaves me with a high sounding RPM engine that I can hear from the cockpit. Only time I can hear pops now is while doing quick accelerations and even those don't really sound the same, its like something is trying to block the noise.

3.5: Lets say I'm in second gear working the engine up to 4500-5000 rpm and fully release the gas, I get no exhaust sound whatsoever and actually its almost like the car gives gas to itself for some reason because it doesnt slow down like it used to. It's like its running on cruise controll slowing down really slowly.

4:I just noticed yesterday that the Auto start/stop function hasn't worked AT ALL in the past week, so i experimented with it a little yesterday and no, it doesn't work at all. I just notice at the digital box right under the RPM meter when I fully stop that the Auto start/stop symbol shows up with a big / covered.

Would just like to throw this in somewhere. When I rev the car in P/N mode it sounds pretty much like it should.
So from a scale of 1-10 how worried should I be right now. I'm currently at 11-12 somewhere.

[B58togo]

Auto stop/start isn’t working because you inadvertently turned it off. That’s why it has a / over it. You can turn it back on with the button above the start button. I wouldn’t be worried about any of it. It’s under warranty.

[coldM2]

Originally Posted by B58togo

Auto stop/start isn’t working because you inadvertently turned it off. That’s why it has a / over it. You can turn it back on with the button above the start button. I wouldn’t be worried about any of it. It’s under warranty.

I know about that button and it has been on the turn off mode always. New car warranty ended last month the 13th..

[YasM3]

Are the valves on the exhaust opening?

[coldM2]

Originally Posted by YasM3

Are the valves on the exhaust opening?

Yeah, the different drive-modes still open and closes the valves but even though they're open it just does not sound right. As I wrote the only times the car sounds like it should is when I'm either in comfort/eco mode or when I'm revving it in whatever mode. :/

[AlpineAl27]

Originally Posted by black340

Yeah, the different drive-modes still open and closes the valves but even though they're open it just does not sound right. As I wrote the only times the car sounds like it should is when I'm either in comfort/eco mode or when I'm revving it in whatever mode. :/

As for the "cold start" every time you start the car, that is normal. I've had my 340i for 3 years and it has done this every single time i start the car, annoying but normal!

[NISFAN]

Sounds like you have throttle input even at zero pedal movement. Search for and try the throttle adaptation reset.

[rockymtnpilot]

Originally Posted by NISFAN

Sounds like you have throttle input even at zero pedal movement. Search for and try the throttle adaptation reset.

This. Had to do that pretty early on with mine.

[coldM2]

Originally Posted by NISFAN

Sounds like you have throttle input even at zero pedal movement. Search for and try the throttle adaptation reset.

This could be possible! But it's super minor though it's barely noticeable if you haven't felt how it drives before! I could try this could you please provide me with a video or explain how to do this? Thank you.

[coldM2]

Originally Posted by Estoril Al

As for the "cold start" every time you start the car, that is normal. I've had my 340i for 3 years and it has done this every single time i start the car, annoying but normal!

Many people misunderstand me on this. What's wrong is that it doesn't have the loud cold start anymore, when I turn it on now it goes straight to some sort of quiet mode.

[AlpineAl27]

Originally Posted by black340

Many people misunderstand me on this. What's wrong is that it doesn't have the loud cold start anymore, when I turn it on now it goes straight to some sort of quiet mode.

Ohhh I see, nevermind then lol that's definitely not normal as far as I know. Unless they issued some sort of update. I'd get it checked out.

[jpsimon]

Originally Posted by black340

Many people misunderstand me on this. What's wrong is that it doesn't have the loud cold start anymore, when I turn it on now it goes straight to some sort of quiet mode.

Probably not the case but maybe the wastegate is stuck shut? During a cold start the wastegate is normally 100% open

[coldM2]

To be honest, what NISFAN said about having a throttle input at zero pedal movement could possibly be the solution to all the issues, but again the throttle input seems so small that even though there is some sort of input it should still pop a lot more. I will try this method beneath and update:

"( * Press the start button once to turn on power (Don't start the engine)
* Press the accelerator down to the floor for at least 5 sec.
* Hit start button once to turn off power
* Remove foot from accelerator
* Wait for min. 2 minutes
* Start the engine and drive )"


Went out to try this now at 1AM so I just heard it with a startup and it sounds the same unfortunally.

[coldM2]

Originally Posted by jpsimon

Probably not the case but maybe the wastegate is stuck shut? During a cold start the wastegate is normally 100% open

What is a "wastegate"?

[Nebelhinten]

Originally Posted by black340

What is a "wastegate"?

There is a wastegate valve that stays open during cold start to allow bypass of the turbo. The idea is to warm up cat quickly. The turbo has a muffling effect that is bypassed during the cold start resulting in louder exhaust until valve closes.

[coldM2]

Originally Posted by Nebelhinten

There is a wastegate valve that stays open during cold start to allow bypass of the turbo. The idea is to warm up cat quickly. The turbo has a muffling effect that is bypassed during the cold start resulting in louder exhaust until valve closes.

Ohh alright, sweet! But I'm still questioning the slow downshifts, any ideas for this..?

[Nebelhinten]

Originally Posted by black340

Ohh alright, sweet! But I'm still questioning the slow downshifts, any ideas for this..?

No, and not sure your wastegate is actually closed during cold start. Just giving you idea what it is and how it works. Good luck, BMW should be able to sort out your issues when you bring it in.

[coldM2]

Originally Posted by Nebelhinten

No, and not sure your wastegate is actually closed during cold start. Just giving you idea what it is and how it works. Good luck, BMW should be able to sort out your issues when you bring it in.

Hopefully, got an appointment next thursday...

[coldM2]

Alright so I turned my Bmw in for troublshooting today and the results are too funny. First I waited 30 min for them to decide that they needed to reprogram the car. The reprogramming took about 2 hours so I waited. When they were done they told me that they fixed the popping burbles, and exhaust problem that I mentioned but they told me that they had no idea why the "Stop and Start" function dont work. They proceeded to tell me that I should book another appointment for them to troubleshoot the car yet again. I decided to take the car out for a test to check if they fixed the problem. Once I started the engine I noticed that it still had the same kinda unusual startup sound issue as before but the car felt a bit louder to be honest(might be some sort of imagination). I proceeded out on the road to test the downshifts and throttlerelease and its exactly like before, no pops nor burbles. So I turned around and entered the Bmw dealership again and told him that I have no idea what theyve fixed but the car still does not sound right. He proceeded to tell me that the mechanics are M-specialists and that they say it sounds like it should. Really dont know what to do next...

He did tell me that the pops and burbles on downshifts depends on circumstances, and I told him that the car popped and sounded just like it should the day I testdrove the car and 4-5 weeks further on, and now it hasnt popped at all for a month. Only time the car pops is when I push the throttle in either park or neutral.

[insanecoder]

Did they reset adaptations at all?
I'd ask exactly what they did

[aleki75]

Ask them to drive a comparable vehicle on their lot to compare it.

[Tribalpinoy911]

How is you're warranty up and you have a 340? You hitb50k already?