Hello,

This is for a 1992 300D 2.5 turbo.

Can having bad injectors or a bad injection pump cause your car to spit blue smoke and rough idle/shaking?

Theres a lot of blue smoke at start up and at cold start ups, then there is just a tad coming out when idle. I just got my car back from dent wizard who just got the car from the MB dealership.

According to the dent tech, the MB dealership said the cause of the blue smoke and rough idle is due to a bad injector, does that sound right to anyone? I was always under the idea that blue smoke means burning oil, which I do not burn a drop of oil between oil changes. Thanks in advance.

Johnson,

Have you fixed the problem?

David

Hello David,

No I have not fixed the problem. I also found out that I have low compression in one cylinder and I honestly dont see the point in putting money into this car. Expecially if I dont plan on keeping it much longer. Thanks for asking.

Johnson

I agree that its probably not wise economically to deal with low compression on that car if it has over 150k. It can still be a good car, just not economical.

BTW diesels do not blow blue smoke from burning oil. Diesels will run on oil. Blue smoke comes from incomplete or inefficient combustion. Causes include: compression, fuel delivery (injectors), timing. Anything that approaches a missfire.

There was a certain amount of discussion in the x66 thread about diesels and carbon. I have seen carbon freeze the rings on many a low mileage motor. Before throwing the beast away, I would do an intensive diesel decarboning plan. There are a number of additives that may do it: Redline (is the one we use) and Techron are two I know about.

Steve,
To decarbonize a diesel , do you just add the ingredient to the gas tanl or is there another preferred method? What Techron product do you use? I have only see Techron, the gasoline additive.

Yes, added to the tank. I think the Techron is the same for both gas and diesel.