OM602 smoking, noise.. new to forum and Benz

[Bigjake34452]

Hello everyone, new member from Florida, been lurking for long time finally registered.

I’ll start by saying I have purchased a 92 300d with 197k from a friend of mine of who owns a shop down the road from mine. Knowledgeable guy he does not do bad work. He had smoke issue from this car and assumed head gasket so he replaced the gasket had head checked all was good. Still smoked so there it sat for 4-5 years until I bought it.

Fast forward I have replaced all filters including tank screen, fresh fuel added. Changed oil and filter with a syn blend 15w40.

Issues I’m having is there is a constant smoke haze that’s blueish white that smells of fuel and burns the eyes. No matter if it’s cold or hot, idling or at speed, it’s always there. As well as a hard knocking sound I assume is nailing until the car has ran a good 20 minutes, or if the rpm gets above 1400rpm or so it will also stop the noise. During this period where the car is making this noise and is cold the whole car vibrates a decent bit, but if I loosen each injector line it will miss pretty hard with the same change for each cylinder, none of them seem to have less of an effect than the other. Once it has warmed up this vibration goes away, BUT I’ve noticed a low rpm miss when warm, like 700-900 rpm range there is a spot that you can hold the rpm and it misses terribly. Above or below that rpm is smooth as can could be. Also no matter the temperature this car starts incredibly easy, seemingly one revolution of the starter and she’s on.

I haven’t done a whole lot in the way of testing anything yet, would love some ideas of what I should look for and test for. From lurking I see lots of folks talking about delivery valve seals and washers, I will be replacing those but my IP is bone dry up top , no fuel leak.


Sorry for such a long first post but I greatly appreciate this forum and everyone’s insight , thank you