CLS 350 CDI black smoke under acceleration, extremely bad.

dillbar123

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So it appears I am having an absolute nightmare, my Mercedes CLS 350 Cdi throwing out big clouds of smoke under acceleration!

The history of the vehicle and things that I’ve already checked:
Firstly I’ve not owned the car long, it was in an accident 4 weeks after owning it. I bought it back (as a category S write off) and fully repaired it myself. (There is a thread on this in bodywork)

However this issue is completely unrelated, and has only came about 1 week after getting it back on the road.

so firstly there is no engine codes, The car seems to be running well. pulls really well and accelerates fine. However under load/acceleration creates black clouds of smoke.
firstly I checked injectors, they all seem fine. They have been cleaned directly through the rail, and also ran a bottle cleaner through fuel just as troubleshooting to see if I changed anything.

Check the map sensor all fine and reading correctly removed and cleaned it anyways.

replaced the DPF pressure sensor as it’s cheap and is often the problem when it comes to running Rich. Still exactly the same.

I stripped the intake down cleaned all the air filters they weren’t really dirty at all as it’s recently been serviced.

Checked for boost leaks all pipes are fine. Had it on ramp, definitely no boost leaks 100%

One thing I did notice which I am going to go back to, is when stripping the intake down, I seen that there was oil in the turbo, and the intake seem to be a bit oily, this did not get to the air filter, and I cleaned it all out. But it has me thinking whether the MAF sensors may be dirty, so I have went and ordered a cleaner online.

i’m really clutching at straws here, and I’m not sure what to do. Funds are very limited to spend on the car since repairing after Crash, however I do have access to a garage and my friend is a mechanic, I have access to a snap on scanner too, definitely no c
The back of the car is black
163909DA-090D-4AC6-B395-A0454A29DC19.jpeg
 

mersum1es

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turbo itself? Lubracation oils all going intake? Is there a play in turbo shaft?
 

DSM10000

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Have you checked the Oil seal in the intake to Turbo pipe, both the large seal and the small one? ?

Is there any play in the Turbocharger shaft?
 

E55BOF

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Black smoke is usually indicative of overfuelling; oil smoke is usually blue/white/grey. Is the black deposit on the back of the car more oily or more sooty?
 

st13phil

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Black smoke is usually indicative of overfuelling
^ This.

Assuming the smoke really is black, a wastegate partially stuck open can cause overfuelling. Had this issue on a VW Passat many years ago and - oddly - performance still seemed strong, so definitely worth checking.
 

Bellow

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Checked for boost leaks all pipes are fine. Had it on ramp, definitely no boost leaks 100%
Unless you could replicate full boost then I doubt the above as a valid test.
Cracked intercooler (accident damaged?), stuck wastegate (as per above post), etc. Something depriving it of air at full stomp by the looks.
 

KeithJG

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Try decent Shell fuel instead of cheap dirty other brands?.........you should notice a great difference?

Had the same on visiting the French Pyrenees on the motorways back of the car was black from crappy diesel........back home no problem with decent fuel.
 

Larkone

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Doubt it is the black smoke problem but I would also check the PCV (crankcase breather) pipe as they have rubber diaphragms that degrade and split allowing oil into the intake at the point it joins the turbo, hence excess oil there.
 

AndrewOl

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Do you know if the car has been re-mapped? If the dpf has been cut out it will smoke under heavy acceleration.
 

MrGreedy

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Do you know if the car has been re-mapped? If the dpf has been cut out it will smoke under heavy acceleration.
Just going back to this, should one of these OM642 engines ever smoke heavily if a DPF is fitted?
Genuine question as I don't know the answer.

What I do know is that some people take the DPF off for some makes and models and smash the insides out, so it might not be apparent from an external visual look. Does anyone know if this method could be employed on the OM642?


As you have a code scanner, can you check if it's doing or trying to do a DPF regen? Exhaust temp sensor will show from around 400 degrees whilst initiating, quickly up to 650 degrees when doing the regen.
 

MrGreedy

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Sorry, forgot to add.
Oil around the turbo inlet on the OM642 is very common and comes from the inadequate PCV (positive crankcase ventilation) valve not extracting sufficient oil as part of engine breathing. This makes it's way to the turbo inlet like you have seen. It is recommended to clean this inlet area and change the seals regularly (I would say annually) to keep oil on the inside, as otherwise a weak seal will allow the oil to drip on your swirl flap motor and this has caused a small number of failures of the swirl flap motor.

As said by DSM10000 and Bellow above, check the play on the turbo. If there's basically no play, the oil is unlikely to be coming from the turbo.
 

Bellow

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I'd properly investigate the dpf situation .
So the OP now has to spend time and money just to check that his car hasn't been bodged in the manner so frequently recommended on this forum - wow!

OP: That the car was fine before the accident probably excludes the possibility of a tampered with DPF.
 

Gazwould

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Could it of broken up inside at all with the impact , not just a bumper tap but Cat S structural damage wack ?
 

Bellow

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Could it of broken up inside at all with the impact , not just a bumper tap but Cat S structural damage wack ?
Grudgingly - I'll give you that one......
I'd be interested to know more about the shunt it was in and what in the way of induction pipery was replaced subsequently and what remains.
 

Tuercas viejas

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The age old diagnostic approaches apply here.
Get the injectors out and have them tested at a Bosch service centre.
Then look for air starvation like EKAS perhaps.

You have to start somewhere ,like is the FIE dumping fuel into the pots for a mechanical issue in the making .
Its called base lining the engine, harking to an expression from a foul mouthed ex WW2 RN Bosun I work with as an apprentice .
Any blue or grey or any white????
Take the engine up to max gov control revs, does it bark or hunt ?
Tuercas Viejas
e
 
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dillbar123

dillbar123

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Grudgingly - I'll give you that one......
I'd be interested to know more about the shunt it was in and what in the way of induction pipery was replaced subsequently and what remains.
As I mentioned before the photos of the accident were available on another thread in bodyshop section. The damage was very minimal. And a knock is not going to break a cars DPF, unless It gets hit from the back, and bent.

I took the DPF off last night, Photos to follow.
i’ve also attached photos of the damage to the car to silence the straw clenchers. If I wanted stupid ideas I would take it to Halfords. D93A8DD6-F9A1-402A-9748-87371D17244E.jpeg
 

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