Engine burning a los of black smoke


#1

Hello. i have a nissan frontier 2002, and one day suddently a lot of black smoke satrted to come out of the tail moffler. I took it to the machanic and he thoght it was a problem with the valves. After checking and cahnging the seals on the valves the engine continues to expel a lot of black smoke. What else could it be? please help.


#2

Black smoke is a sign of too rich a fuel/air mixture. If your mechanic was changing valve seals to cure this then you need to find another mechanic because he headed off in the wrong direction.

Since this problem occurred suddenly the first suspect should be a fuel pressure regulator diaphragm that has let go. This is easy to check and replace if that is the problem.
There are some other possibilities but the F.P. regulator should be the first thing to look at. Disconnect the vacuum hose and note if there’s gasoline inside the hose. If so, there’s your problem.


#3

Black smoke is a sign of too rich a fuel/air mixture. If your mechanic was changing valve seals to cure this then you need to find another mechanic because he headed off in the wrong direction.

OK is 100% correct. Black smoke is too rich fuel. Find another mechanic…FAST.