Originally Posted by 240DieselDog

By smoke, am thinking you mean external diesel fuel cooking at the injector indent on the cyl head. First thing I'd check is return lines, then the coupling where the tube meets the injector. I once cracked the pipe under the fitting where it meets the #1 injector on my 240D by NOT attaching all the pipe couplings, it cracked right above the flared end of the pipe probly through engine vibration. What makes you accuse the pre-comb chamber of leaking? If it was me I'd suspect installation of the injector.