Black Smoke during heavy accelleration. Does thing mean that the timing should be checked?

Thanks
Haney

84 300td 80K
PS: With new radio wiring issues, from all the posts I read the front ones should of been the hard ones to by pass the fader. They work fine, the back ones need rewiring. I have a black,brown,grey,and red off of the harness, radio works but no memory. Not shure what the stray black one is for either.