black smoke 83 audi 5000td

[jetta2nv]

I have an 83 audi 5000td and i notice that when i flow it there is a cloud of black smoke. The car seems to run well and the engine is smooth. It also only smokes when i floor it. This is my 1st diesel and i dont know alot about it. I was told that there might be a problem with the timming on the injector pump. Does anyone know if thats the case? I've been keeping an eye on the oil and i know that its not burning any so the problem has to be from fuel. I'm also getting about 33mpg and that seems a bit low to me. One more problem that i have noticed is that sometimes after the turbo hits full boost the boost will then drop off and it will not build boost again unless i come off the gas and hit it again. Any help would be great thanks.

[andy2]

Sounds like the wastegate could be sticking.You need to apply 10-15 psi of regulated air to the wastegate,then quickly release the air to see if you can hear the wastegate snap closed,if you cant hear it close then it is likely not working right.You could remove the wastegate to verify that its working also.