Om642 heavy black smoke

[Gurkus]

Hello, I have 2006 om642 3.0 diesel engine with 218hp, its fitted in Chrysler 300c, but its a mercedes engine, so i hoped that someone might help me there.
Issue started about 4 months ago, the old turbo went bad, no metal particles fell of, but inside of the turbo where the regularor pins and "valves" are, the ones that are moved by actuator went bad. Heavy black smoke, no power at all, car struggling to get to 30km\h, jerking, p0299 fault that there is not enough turbo pressure. I bought completely new turbo with new actuator, cost me 700eur, it accelerates now ok, but it still makes ton of black smoke, very dark black smoke, not blue. When engine warms up and i accelerate, at around 80km/h it goes limp mode and throws p0299 - low turbo pressure. Injectors have 35k km on them, still sent to testing, they all were just fine. All filters are changed. I changed the pressure sensor as well. Changed intake seal before turbo, changed all the seals of exhaust, tested the intercooler for leaks, its all good. But still the same thing - limp mode. Took out the egr valve, it seems fine, i had a working used one from the spare engine, swapped anyways, but nothing had changed. So i have no idea, what else could it be. Depeted dpf, so i expect it to have a bit of smoke, but now its so bad that i accelerate at the traffic lights and cars behind me just go invisible.

 

[onefortheroad]

Split or detached hoses?

 

[brandwooddixon]

Heavy black smoke is normally incomplete combustion due to lack of oxygen.
This is either over fuelling or burning of another liquid, like engine oil. If you hadn't bought a new turbo, I would suspect that and combustion of a lot of engine oil leaking past seals.

Perhaps an inspection of the inlet and boost pipes for oil residue would be a start. A light covering is expected from most turbo charged engines in the boost pipe. If found give them a clean in case any of this is due to the previous turbo failure.

Then I might suspect over fuelling. I don't know this engine very well, but I'd suspect a contaminated air flow meter or a turbocharger that isn't producing the boost expected. Beyond that you have issues with fuel pressure, but as your car seemed okay before I suspect not.

If all of these areas look okay then I have to ask, could the engine have ingested any material from the failed turbocharger? Perhaps a compression and leak down test on the engine is required.

 

[Gurkus]

Split or detached hoses?

I tested with as much as i could, doesnt seem like that. Held 1.2bar pressure nicely.

Heavy black smoke is normally incomplete combustion due to lack of oxygen.
This is either over fuelling or burning of another liquid, like engine oil. If you hadn't bought a new turbo, I would suspect that and combustion of a lot of engine oil leaking past seals.

Perhaps an inspection of the inlet and boost pipes for oil residue would be a start. A light covering is expected from most turbo charged engines in the boost pipe. If found give them a clean in case any of this is due to the previous turbo failure.

Then I might suspect over fuelling. I don't know this engine very well, but I'd suspect a contaminated air flow meter or a turbocharger that isn't producing the boost expected. Beyond that you have issues with fuel pressure, but as your car seemed okay before I suspect not.

If all of these areas look okay then I have to ask, could the engine have ingested any material from the failed turbocharger? Perhaps a compression and leak down test on the engine is required.

Its totally new turbocharger. No particles of old one flew out, wings were intact as well, the flaps in turbo just got so loose that they couldnt make the pressure. If i stop accelerating at around 75, then slowly till 85, i can go hard until 130 again with no problems and it goes in limp mode then. I think that if it was compression issue, i would have the issue at any speed when hard accelerating, but it detects too low pressure only when its warmed up and at 80 or what i told earlier - st 75 slowly until 85 and then i can go again, it does not detect too low pressure then.
Also, like three times of ten when accelerating its fine and there is barely any smoke.

 

[Doug1234]

Is it getting enough air ?
Air filter blocked / wet
Not enough air getting into engine = low boost because it cannot make boost any due to lack of air.

So my take is it’s struggling to get enough air to run but it can accelerate hard enough on what air is available until it needs more than it can drag in

 

[Almichie]

As others have said, black is too much fuel. Low turbo pressure could be due to a suction loss, blockage or turbo failure. How were the oil lines when you changed the turbo?
a turbo is a centrifugal compressor, which creates flow by creating lift like an aeroplane wing, if you stave the suction side it won’t create lift and won’t deliver the pressure needed to meet the fuel demands At the point in the engine mapping.

 

[M80]

Doesn't a new turbo need calibrating to the engine?
Or the ECU adapted to it?

 

[Doug1234]

Not on these , not on Chrysler or Jeep anyway it’s just fit a new one and drive. Same engine in my 06 Jeep , one maf and one large airbox .. nothing complicated really like the Mercedes.

 

[LostKiwi]

Black smoke is always excess fuel for the air being measured into the engine.
The MAF tells the ECU how much air it's flowing and the ECU provides fuel accordingly. Therefore the MAF is seeing more air than us actually present at combustion. This is almost always a boost leak from hoses, a holed intercooler or a poorly sealing connection.