CM871 smoke at idle...?

[Lonestar10]

i would look at your valve cover plate and CPL number confirm that your truck is actualy a CPL that can do 525HP you might not have all the correct parts I.E. small/large turbo, injectors, cams and ect for a 525 Tune. if your truck isnt setup to run that horsepower it might be overfueling at idle due to mismatch between the cummins tune and what your engine can handle.