Truck Repair: L10 smoke, national warranty, freightliner dealer

Question
I have an L10 with terrible smoke on idle clears out under load, however under acceleration it acts as if the afc is not working,(smokes black until boosted up) it is an L10-310 cpl of "1349".
customer brought this truck to me after takeing it to a freightliner dealer and spending $10,000 with out the problem being solved. local cummins shop refused to work on it because of the freightliner issue.( said it was their problem) any ideas where to look?

Answer
Could be AFC problem or something in the pump.You used to could get a Cummins ReCon pump for cheaper than getting it rebuilt at a pump shop with national warranty & get it the next day.Dont know why they refused to work on it.Maybe check fuel line restriction to the tank.