Ric_Tro

Hi all members , i hope i can get some help from the experts on this forum.

I bought a very nice one owner 2004 W203 C180k auto for a good price with a terrible misfire , it is so bad that you can barely pull away from a standstill and it shakes and misfires almost sounding like a damn diesel

I started checking the obvious so my testing so far went as follows
Started the car and picked up a rpm a bit , i then proceeded removing the coils from the spark plugs one by one.

Plug one makes the rpm drop and car misfire even more , plug one back in plug two out same story plug 3 does not make as big of a difference amd plug 4 does absolutely nothing so when the car misfires at 1500rpm i can remove and reinsert spark plug 4 coil and nothing happens , i swoped out coil 1 and 4 and 4 still has the problem , i removed the spark plug and checked for spark and it sparks

I then removed the airbox etc. To gain access to the fuel rail
having the engine run i removed the plugs from the fuel injectors one by one and that went as follows.

Remove plug from injector on piston 1 idle drops , reinstall plug and remove plug from injector on piston 2 idle drops severely , piston 3 also reacted a bit and again piston 4 did nothing at all.

I removed the injectors and tested them with a 9 volt battery and all the coils open i have a sonic cleaner that i use for reloading firearms so i ran them in there for a few cycles and reinstalled them on the fuel rain in the car.

I cranked the car and they spray very beautifully and on the right firing order and look pretty good , i reinstalled everything and the car is still misfiring and has the same issue.

whats next? Cam timing or something to do the that? In all my adventures i did see the cylinder head has been removed before as i can see copper gasket sealer and rtv silicone on the parts.....

Whats next....

MJ50

moved to W203 forum...