Mercedes Sprinter 311 cdi LWB 2006

Hi I have the van above, when the reserve fuel light is on it runs fine, however when i fill it up past reserve with diesel it starts smoking intermittently. SOMETIMES turning the engine off and back on resolves this. The smoke is white and comes from the exhaust. It smells like unburnt diesel. the van has covered approx 180 000 miles.

 

The exhaust was stolen about 4 years ago and replaced by the insurance company for a copy. The ecu was causing problems and was changed from someone who claimed to be a mercedes specialist, i feel like he charged me for a new one but put a second hand one in. The van had been running ok after replacement of ecu too about two years ago.