Hello, this is first post with you guys, just bought my first mercedes and see why everyone loves them.

I do have an issue that I cant figure out, When engine is cold, like sitting overnight it starts and idles perfect, it also drives perfect. When I stop the engine after getting to operating temp, and go to start, it starts but 7-10 seconds later it bogs down and stalls out, if i start and keep around 1000rpm until it bogs it will stay running, and run fine for entire drive, no sputtering or hesitation ever. Why? What is the issue here?

Also in rear of car there is a loud humm sound when running, is this fuel pump or something else, its not super loud but can hear inside and outside.
Thank you in advance..

Mike

 

Sorry to hear that you Merc is giving you a fit. Can you answer the following questions so that folks can help?

1. How many miles are on the car?
2. Do you know about any of the maintenance that was done on the vehicle?
3. Do you know anything about the history of the car? Owners etc??

I'm thinking that perhaps a few likely things are wrong here but will defer to the real mechanics who lurk on this site. I'm curious as to what your issue is. I hope it's cheap and simple and you can do it yourself. Good luck. Be patient as someone will chime in shortly.

 

Car has 142K miles
Previous owner that had this vehicle took extremely good care, mechanically and cosmetically. Used all proper fluids for flushes, if anything happened he took care of it, this is only issue he told me about when I bought it.
The maintenance booklet is filled out till 45K miles from first owner, I know of 3 previous owners.

Thanks for the warm welcome, its nice that people still look out for one another when they can. Im still doing my own research and will look @ some parts under hood tomorrow, I just bought today and ran out of daylight when I got home to do anything.

Thanks again.

Mike

 

well, here's my experience with my first MB. Same things...turned out to be the coolant temp sensor and new plugs. Car ran great from cold start, the warmer the engine got the more goofy it acted to the point of hesitation upon acceleration, difficult warm start, poor fuel mileage and outward nondrivability to the point where the wife didn't want to drive it any longer. This on a 1990 300TE...runs great now, although I will throw a complete tune up at it in the spring. Plus the idiot who I bought it from had put synthetic oil in it. Replaced that with proper mineral oil, thankfully no seal leaks. Runs great now for around $100. good luck

 

Thanks, I'll look into that, I planned on checking the plugs today put had a lot of running to do. The stall after 7 secs is only issue, it doesnt hesitate(yet) and I think the gas miliege is pretty good, on my first fill up I got 21mpg and that was mostly city driving. Dont know what norm is.

The guy I bought from has run Mobil 1 in it, and thats still in there, are you not supposed to but synthetic in this engine, I figured it was better.

Thanks for response.