SLK200 sudden misfire?

[Graham couch]

hi my SLK200 suddenly started misfiring as though it was only running on two cylinders, also the engine light came on, however when I turned off the engine and restarted it, it started running fine, although the engine light is still on and has run ok ever since, any ideas guys?

 

[Wighty]

Maybe moisture near the spark plugs which has now cleared ? Sometime the engine light will go out after a few starts when it runs ok . And welcome to the forum .

 

[Graham couch]

Thanks for the reply, it's going in for a diagnostics test on Wednesday, it's running fine now but I need the engine light turning off

 

[LostKiwi]

They can turn off the light at the diags test.
It may also turn off of its own accord if it has three consecutive 'long starts' without error. A long start is one where the engine reaches normal temperature and runs for a preset length of time.

 

[Graham couch]

Thanks guys I'll run for a while and see how it goes and keep you updated

 

[Graham couch]

Exactly right chaps it's running ok now and the engine light has gone off after a few starts, thank you all

 

[Wighty]

Thanks for the update Graham

 

[LostKiwi]

Glad you got it sorted so easily.

 

[John Laidlaw]

Good stuff Graham, nice when we get an update!

 

[Graham couch]

No probs, another query, when I start the engine cold it remains 'tappity' for about 5-10 seconds then goes quiet, its only done 60,000 miles so is this normal?

 

[LostKiwi]

No probs, another query, when I start the engine cold it remains 'tappity' for about 5-10 seconds then goes quiet, its only done 60,000 miles so is this normal?

How tappity?

First things first when was the last service? Is the oil filter new(ish) and hows the oil level? An old filter or low oil level may cause this.

If its really tappity it may be a symptom of worn timing chain/sprockets. If its just a little tappity it'll be the hydraulic lifters getting oil pressure having bled down.
You should probably take it to a trustworthy independent MB specialist to get the chain and sprockets checked.

 

[Graham couch]

Ok thanks, it's intermittent to so puzzling, I've had the oil changed recently which helped it somewhat

 

[LostKiwi]

Ok thanks, it's intermittent to so puzzling, I've had the oil changed recently which helped it somewhat

All M271 engines make a short rattle at start up (part of the way the chain tensioner system works) but excessive noise is a sign of a worn chain and sprockets - sadly a weak point in this engine. Did you get your code read in the end?

 

[Graham couch]

No the engine light went off after a few starts and runs, and its running fine now. Thanks for the info

 

[LostKiwi]

No the engine light went off after a few starts and runs, and its running fine now. Thanks for the info

The only reason I ask is if its a worn chain/sprocket there will be a code logged and it may have been your issue.

 

[Graham couch]

Ah I see, I'll see how it runs for now and get it checked out if it does it again thanks

 

[LostKiwi]

Ah I see, I'll see how it runs for now and get it checked out if it does it again thanks

OK. I'd recommend sooner rather than later and not wait for a repeat. If it is the chain and it lets go it can be VERY expensive but at the end of the day its your choice.

 

[Graham couch]

Ok thanks buddy will do