Smokin' like a burning tire...

My 220D smokes bad... like ... reallllly bad.

When I place on my hand 8 inches from the exhaust pipe, I can feel plooms of smoke PUNCHING my hand in time with the firing cylinders. This thing is dumping a massive, ungodfully sinful amount of unburned diesel smoke into the air.

The smoke is not bluish or black, indicating oil or coolant combustion. It is just gray diesel exhaust ... but lots of it.

My mechanic told me to replace a bad injector that he suspected was stuck open (firing on all cycles) or some similar issue. So I bought ONE injector, because they are damn expensive, and went to work finding the bad injector my mechanic assured me existed. I would replace an injector with the fresh one, start her up, and check for smoke. If she was still smoking heavily, I put the old injector back in and tride another cylinder. Well, sure enough, I tested all four cylinder with the new injector and I got no improvement what so ever. Damnit!

So what to do now? I think I am going to, firstly, pressure test all four injectors at my mechanic's. If they are ALL bad, then I will move on to the injection pump/controll. Any ideas? Advice? Goodbyes?