JaredP

Hey guys,

Recently started having this issue with my C300. I've had the engine die right off of startup twice now, it usually happens when the engine is warm. Happened today for me when I went to the store. Engine was up to temp, went inside for 30 min, came out and started it, and it died right off the bat. Started it up again, and it kind of fought to stay alive, then it was fine. Any ideas on what the issue might be? I have contacted the dealership.

Drazil

Did anything crazy happen to the interior lights or the dash? I had a similar problem with my E where it suddenly went nutso, all the lights flashed and the engine would cut out, even in the middle of driving. When the tow truck showed up, the car started up again normally and everything seemed to be back to normal. I had the truck follow me to the nearest dealership, and halfway there it happened again. Turned out to be a bad engine module and whenever it got warm, it would fail, but when cooled, it would be working again. Cost me $450 to replace.

MikeDaBike

That happened to my 2013 C300 twice. What I did notice was that both times I started the car and put it into gear RIGHT away, not even giving it a half a second. Now I just wait a second or two after i start it before it put it in gear and it hasn't happened again

JaredP

It's happened to me twice too, I don't think I threw the car into gear, it was almost instant. I kind of get a weird engine noise for the first few seconds after a cold start too...

Glyn M Ruck

Check fuel pressure at the front rail. It should be > 3.8 bar or 55 psi while cranking. Could also be the CPS (crankshaft position sensor) if it is more inclined to happen with a hot engine.

Make sure the airbox is clipped down firmly over the MAF at the rear.

JaredP

Thanks for the tips, I haven't had it happen in awhile.

JaredP

Here is a video of the engine sound on startup. I believe something stemming from this is causing the stalling.

C300Sport

Agree with Glen in that it may be a fueling issue.
I know you said it is usually warm so it made me think vapor lock, but that is pretty rare with today's cars.
May also have a small leak in your fuel system bleeding off pressure??

JaredP

Hopefully it's nothing too big. The town I currently live in does not have a merc dealership, so I'll have to drive 3 hours to get it serviced. Hopefully it only takes one trip.

JaredP

UPDATE: So apparently, there is a software update for the GDI 2013 engine specifically for this issue. I'm picking up my car tomorrow. Just an FYI for anyone with this MY.

Glyn M Ruck

Interesting. Thanks for letting us know. I wonder what they changed????

ralawren

I am experiencing it also with just 800-900 miles. Will contact the xservice rep at local dealer. Thanks

JaredP

Yes, I believe the 2012 C350 has the M276 as well so it could be a problem. I got the problem at around the same number of miles. I still have engine knocking on a warm startup, but this has pretty much been deemed "normal"..

Properstyle

Maybe I'm a little overly logical but If i was driving a 2013 anything and a start up issue occurred I wouldn't on a forum tryning to solve the issue the car would be going back the dealer ship with me getting a loaner under their expense.

JaredP

The first thing I did was contact the dealership. I posted this in hopes that it would prove valuable to other members, and it is already apparent that it was. Why revive an old thread that you didn't read just to be a douche?

Properstyle

Wasn't being a douche I was just saying, as in your thread you never stated at the begin like you should have the at car was at the dealership. You posted this on the 8th and didn't even mention going to the dealership until the 12th. Then didn't reply until the 20th that is was a software issue. Had that been be I would not be making the trip, Mercedes would have been sending a flatbed to get the car... I read the thread but like many others I see the owner always tries to solve it first instead of just leaving it to the warranty to fix and solve from the jump.

JaredP

Do you honestly think I would detriment a $50k vehicle by driving it if I wasn't advised to do so? I was in contact with my dealership since day one, and it was simply an afterthought to post here. As far as the dates go, I can't bring my car in whenever the hell I want. It takes 6 hours for me to get to a merc dealership and back. I waited until the weekend, drove up, rental car back, and did the same thing the next weekend, driving my C back.

JakeMerc

My 2008 C300 has a weak start or dies on startup too. Happens when engine warm. When I go to start it again, it cranks for couple extra seconds then has a rougher start. Idle rpm bit lower, doesn’t respond to gas pedal and alternator isn’t engaged for 20-30 seconds. I know cause I have a device that plus into cigarette plug that read voltage. Then when the alternator kicks in is same time the engine responds to gas pedal.