Volvo: volvo 240 d gasoline motor, mass air flow sensor, mass air flow

Question
black smoke is coming out from the muffler. Is it that  my map sensor  is not working or ist other ignition component. My car star good and runs good except for the black smoke

Answer
Joseph,
The black smoke means that the engine is likely running too rich (too much fuel). That might be a leaking or stuck fuel pressure regultor. Bad MAF (mass air flow sensor). Shorted wire harness. Testing will need to be done to these to help find the fault.