Technical Ducato excessive MAF reading / black smoke

[Ducato Nat]

Good evening. As a newcomer to this forum, I was wondering if somebody could give me some guidance / advice. I have a 2014 Ducato X250, 2.3 jtd engine code F1AE3481D, 160K Miles.
I bought the van a year ago for conversion to a camper. When I got it, it was reluctant to start, eventually narrowed that down to excessive leak off from the injectors preventing sufficient fuel rail pressure on crank. I changed injectors on cyl 1 & 2, starts no problem now.
The issue I have is black smoke under acceleration. When it's ticking over it's fine, passed MOT no problems a couple of weeks ago. I thought maybe smoke issue was due to new injectors not being coded to the ecu so I asked the garage to do that when they had it for MoT. Their tool was unable to communicate with the injector module in the ECU so I took it to an injector specialist, same problem. He did say that the fuel trims were well within spec so he didn't think injectors were a problem.
So further probing showed me that the MAF was reading 17g/s at idle, which seems excessive. Also the MAP was reading 99kpa, also excessive. I pulled the MAP and it was choked with gunk so I thought I'd better have a look in the intake manifold but found it to be clean when I got it off. So the two sensor readings indicated to me that the issue may lie with the throttle body. If I understand correctly the MAF gives a reading of airflow into the engine which the ECU then modulates using the throttle body. The MAF reading also determines how much fuel to inject, so if there's too much airflow everything else gets thrown out. The problem I have is that the throttle body isn't modulating. It remains in the wide open position except on engine shut down when it closes for about 5 seconds. Is this normal or have I got hold of completely the wrong end of the stick regarding how the ECU controls airflow and fuel flow? I've fitted new throttle body also MAF sensor but it seems both of the old ones were functioning normally and the issue lies elsewhere. So if anybody can perhaps shed some light on what's going on with the airflow and also why the injector coding seems to be off limits I would be grateful, since I'm out of ideas now. Also my apologies for the length of this question.
Regards, Nat.

 

[Ducato Nat]

@Ducato Nat how did your car end up? No more black smoke during acceleration? Did you change lambda's? or measure them?

The black smoke issue is now resolved. In my case it was simply the injectors. I still have an inoperable O2 sensor, but that apparently has no bearing at all on the problems I was having regarding the smoke, which stopped as soon as I changed the last injector. As others have said it seems that the 02 sensor is mainly related to the function of the DPF, at least on this vehicle. In my case I suspect that a previous owner may have interfered with this function since MES is unable to communicate with DPF module at present and indicates that a software rewrite was done at 100k miles, ie 60k miles ago. So whilst the van seems to be running well at the moment and has done 1600 miles now on the new injectors with no problems, I need to get it booked in to a remapping company since I want to know exactly what was done to it, and if my suspicions are correct that the O2 sensor and DPF have been electronically compromised.