Hello! I have a c220d 1995 automatic that i had a big problem with, at first i couldnt find out what it was at all and i have tried to replace several things to solve the problem.

Basicly sometimes when i crank the engine it starts for a split second and stops like the diesel flow was cut off. This caused me to replace the diesel pump, and the "brain" or whatever you wanna call it without any change. I had it linked up to a cumputer and there was no error codes present.

The funny thing is that its only about 50% of the time that the car wont start, i mean if it wont start it wont start for an hour or so(if you keep cranking it will suddenly start after 10-150tries i guess), then when its running i can stop it and start it the whole day unless its off for several hours.. Every morning its a looootery, will it start, or not?


So after going crazy, loosing some sleep over it and trying to figure out what causes this i noticed that sometimes the diesel flows back into the main tank, behind the diesel pump in the tube system. "Air in the system" and if i use something to block this tube i wont have the start issue. IE a pinch on the rubber tube, if you see what i mean.

This is really a ****ty solution, and i need to fix it. But as i replaced the diesel pump, and checked all the tubes for leaks of any kind etc i really cant see how this can happen. I should add that the car has stoped sevral times while running on low rpm on the highway, in this situation i can just crank the key and it starts again "wierd"..

The only thing i can think of is something inside the fuel tank, and i would like to ask if anyone had a problem similar to this, that maybe have a solution before i start replacing even more parts and put more work hours into it without any result.



Nvm typos, english is not my native language.

I appreciate any helpfull reply! Beforehand thanks!