Technical Combustion problem.

[ccavalles]

Good morning.
I am trying to solve the problem with my Seicento 1.1. The car had a faulty camshaft sensor wire. Sometimes it would stall and not run combustion properly. I have replaced the wire with a new one, but the car is still emitting smoke and soot. It starts on the first try, no problem with that. The injectors were cleaned. Curiously, it didn't pass the vehicle inspection this year because of emissions; I touched the wire and it passed without any problems. I removed the spark plugs and they were dirty with soot. I put them back clean, but it still emits black smoke. Any idea what it could be? I see all the wiring is fine, coils and wiring were also replaced with new ones not long ago. The catalytic converter is also relatively new, as are the sensors.
When running, sometimes it works correctly and other times it seems like it has no power. But it does not stall.

In the video, more black drops than usual can be seen. I have put some cleaner through the exhaust.

 

[ccavalles]

Of course that's not normal.
It is running very rich or possibly spark itself is very weak there or missing completely.
Does that happen on only one cylinder or across all of them?

the 4 cylinders the same.

 

[bugsymike]

Just a thought based on a Nissan Micra years ago, no error codes and often if started up and driven straight away no issues, however at certain times it would run so rich it would kill the engine and plugs soaked with fuel.
The cause was a temperature sensor and it's wiring connection. Apparently a known Nissan fault at the time and a new modified sensor and wiring was the cure.
What it did was sent a false temperature reading to the ECU saying it was much colder so needed more fuel which soon caused the engine to be excessively rich.
Can you get readings of engine temp sensors and compare with real time temps on your diagnostics?

 

[ccavalles]

Just a thought based on a Nissan Micra years ago, no error codes and often if started up and driven straight away no issues, however at certain times it would run so rich it would kill the engine and plugs soaked with fuel.
The cause was a temperature sensor and it's wiring connection. Apparently a known Nissan fault at the time and a new modified sensor and wiring was the cure.
What it did was sent a false temperature reading to the ECU saying it was much colder so needed more fuel which soon caused the engine to be excessively rich.
Can you get readings of engine temp sensors and compare with real time temps on your diagnostics?

Good idea to investigate. It makes sense. Thank you very much for the help.