I HAVE A 1984 MERCEDES 190 DIESEL 5 SPEED WITH 310000 MILES, IT HAS ALWAYS BEEN WELL MAINTAINED WITH OIL CHANGES EVERY 3000 MILES. THREE WEEKS AGO I WENT SOMEWHERE IN IT IN THE MORNING, IT RAN WONDERFUL, AS ALWAYS, I STOPPED SOMEPLACE FOR APPROXIMATELY 30 MINUTES AND WHEN I WENT TO START THE CAR IT WAS VERY HARD TO START, WHEN IT DID START IT SOUNDED LIKE I HAD REMOVED 2 OF THE 4 SPARK PLUG WIRES, IT WAS IDLEING VERY ROUGH AND SMOKING VERY BAD. IT WAS HARD TO KEEP IT RUNNING AT STOP LIGHTS AS I WAS DRIVING IT TO MY MERCEDES MECHANIC. I LEFT IT THERE WITH HIM AND THE FOLLOWING WEEK HE TOLD ME THE CAR HAD JUMPED TIMING. THE FOLLOWING WEEK HE NOTIFIED ME THAT THE TIMING WASNT FAR OFF TO CAUSE THIS PROBLEM AND HE HAS NO IDEA WHAT ELSE COULD BE WRONG WITH IT. HE HAS JUST ABOUT GIVEN UP ON TRYING TO SOLVE THE PROBLEM, THATS WHY I WANTED TO SEE IF YOU COULD HELP ME WITH IT.
P.S. THE CAR HAS ALWAYS RUN BEAUTIFULLY UP TO THIS TIME. MY NEPHEW TELLS ME THAT IT COULD BE A CLOGGED FUEL FILTER, COULD THIS POSSIBLY BE THE ANSWER? THANK YOU VERY MUCH FOR YOUR EXPERTISE. Del IN RIO RANCHO, N.M.
Just how good is your Mercedes mechanic?
This is an OLD memory as I have not messed with Mercedes diesels in many years. The symptoms you describe may be caused by a little rubber plug on the rear cylinder’s injection system. If you look at the driver’s side of the engine close to the cam cover, there are connections between the cylinders front to rear, sort of looping above. At what would be the begining of the fifth loop, there is a plug rather than a loop. If that little plug is holey, it won’t seal well, and will cause all kinds of odd running issues. Don’t ask me what does, or what it’s for. I don’t know. I only know that the plugs are available in small packages, and when I drove MB diesels I carried extras.