C270CDI blowing black smoke

[stasis]

Sorry guys havent been on the forum lately been busy.
but anyways my C270 CDI is blowing puff of black smoke when you step on it (full theottle). Is this normal?
The engine was serviced about 5000km ago. New air, fuel and Oil filters were installed. Using Mobil synthetics and Shell Diesel . Let me know.

Regards,

Yudy

 

[Ratz]

I have an E270 CDI and experience exactly the same symptoms. I may well be corrected later but as far as I understand it you get black smoke when the engine is overfuelled - which it is very briefly as you floor the throttle. This is only a problem if the car does this all the time you are accelerating indicating a faulty cold start valve (or whatever the MB equivalent is).

 

[stasis]

a cold start valve?! wats that?!

 

[recycled]

could be oil in the intercooler or turbo

 

[BlackC55]

could be oil in the intercooler or turbo

It would be blue if was oil.

There are a few things that cause balck smoke.

1. EGR valve
2. Air mass
3. If you drive it slowly most of the time then occasionally boot it, soot that has built up in the exhaust will be expelled.

Black smoke is basicly unburnt fuel.

 

[tech123]

possibly a split boost hose. they don't always bring on the engine warning light. can you hear any hissing if you drop the windows down and give it full throttle?

 

[stasis]

It would be blue if was oil.

There are a few things that cause balck smoke.

1. EGR valve
2. Air mass
3. If you drive it slowly most of the time then occasionally boot it, soot that has built up in the exhaust will be expelled.

Black smoke is basicly unburnt fuel.

IF it is one of the above mentioned wouldnt the diagnostics picked those faults up? Cos the car was checked with the diagnostic software and everything checks out Ok though

 

[fuzzer]

i used to get that all the time with my 270 from new. Just the way it is on diesels. My 3.0d bmw unit does the same when you boot it.

 

[tech123]

the egr and air mass don't get picked up as faults. you need to check the actual values to see if they're in spec

 

[Dieselman]

Try running a strong dose of injector cleaner or Bio-diesel through it may be suffering slightly blocked injectors.

It is probably just soot build up in the exhaust being blown out as the pressure rises.

 

[stasis]

Try running a strong dose of injector cleaner or Bio-diesel through it may be suffering slightly blocked injectors.

It is probably just soot build up in the exhaust being blown out as the pressure rises.

is it safe to use those fuel system cleaners on the common rail? Will try to check on the EGR and the MAF. From memory when the workshop reseted the fault and i remembered seeing the MAF on the diagnostics list. Will check with the workshop though.

In indonesia the Biodiesel that they have here is a Euro2 spec now means lower sulphur ;evel in the diesel compared to the olden days 3500ppm. But will try it.

Correct me if im wrong isnt common rail diesel overcomes the problem of blowing black smoked when you boot it?! Beleive me or not my other rig (lancruiser 100series) dont blow smokes when i boo it. Cos i sued what they call a "fuel compansator" it prevents the injectors from over fueling the combustion chamber thus no smoke at all. I still fing it hhard to believe tha the common rail diesel blows smoke so easily especially in the BMW since its a 3rd generation of commonrail compared to the 270cdi a seconf generation common rail?

 

[fuzzer]

is it safe to use those fuel system cleaners on the common rail? Will try to check on the EGR and the MAF. From memory when the workshop reseted the fault and i remembered seeing the MAF on the diagnostics list. Will check with the workshop though.

In indonesia the Biodiesel that they have here is a Euro2 spec now means lower sulphur ;evel in the diesel compared to the olden days 3500ppm. But will try it.

Correct me if im wrong isnt common rail diesel overcomes the problem of blowing black smoked when you boot it?! Beleive me or not my other rig (lancruiser 100series) dont blow smokes when i boo it. Cos i sued what they call a "fuel compansator" it prevents the injectors from over fueling the combustion chamber thus no smoke at all. I still fing it hhard to believe tha the common rail diesel blows smoke so easily especially in the BMW since its a 3rd generation of commonrail compared to the 270cdi a seconf generation common rail?

Ive had loads of common rail cars and they all blow smoke. The only ones that don't are the EU4 spec cars with the particulate filter on them. Thus the point in having the particulate filter.

 

[Satch]

Hence the need to take such cars for a pre-MoT thrash. Once, after Mrs S. had been pootling around for week, took the car out and booted away from traffic lights to get away from a twerp in a Nova. Appalling smoke screen laid down just from sott being coughed out.

Use of injector cleaner is pretty much essential unless you use a premium diesel and even then worth using now and again.

 

[eurico]

Here goes:

Modern Diesel engines work on very "lean" air/fuel mixes. This means little enthalpy (thermodynamic property of a fluid that enables it to produce work in a turbine or heat up things, to cut things short), or very little heat going by exhaust. If thing's where unaltered, when you needed some more rip, the turbo would take ages to get going and produce any noticable pressure. To cope with this, modern cars tend to over fuel when more response is needed. They inject more fuel and later that is burnt in the exaust manifold, lighting the turbocharger turbine alive - this was used quite interestingly in the first Mitsubishi evo's - they retarded spark so much at lower revs that the fuel was burnt way past the exhaust valve open and that enabled the very large fixed geometry turbo to be kept awake and ready. This way we can all have the enormous torque available to make us smile. This also means a little black cloud behind us because the cumbustion process is less clean - it is also a means to confuse anybody that is chasing us...used for ages in moluscs!
You have a problem when the turbo awakening process is over and smoke keeps being belched out.
Try:
1) Injector cleaning fluid
2) EGR valve clean-up and verification
3) Air mass sensor clean/exhchange
4) Fuel/ar filter exchange

Fuzzer mentions: "Ive had loads of common rail cars and they all blow smoke..."
A friend of mine has a 2.2 HDI Pug and when it was time to replace the particulate filter he just tossed it away and welded a direct tube - the tosser! Result was a real squid of a car that since it still tought that it had the DPF filter, overfueld the acceleration phase so much, no one could chase him properly without wondering "where did he go..cough! cough!"

 

[c240yaz]

First question I would ask is, How many thousand miles / klicks has your engine done ?

In addition to the possible causes listed above,

Black smoke is ussually too much fuel or not enough air entering combustion chamber. A dirty air filter causing poor air supply is also a common cause. Although having very little hands on experience on diesel cars, I cannot imagine the reasons being too much different from HGV Mercs, Volvo, Gardner, MAN engines etc.

Blue smoke ussually means that the engine is burning oil. Valve seals, piston rings etc.

White smoke, is un-burnt fuel, caused by pump timing / phasing / calibration / dripping injectors, especially on the exhaust stroke. One other cause of white smoke is head gasket blown between water channels and cylinder which creates steam. Very common and frequent on HGVs.

 

[Dieselman]

Modern Diesel engines work on very "lean" air/fuel mixes. This means little enthalpy (thermodynamic property of a fluid that enables it to produce work in a turbine or heat up things, to cut things short), or very little heat going by exhaust. If thing's where unaltered, when you needed some more rip, the turbo would take ages to get going and produce any noticable pressure. To cope with this, modern cars tend to over fuel when more response is needed. They inject more fuel and later that is burnt in the exhaust manifold, lighting the turbocharger turbine alive - this was used quite interestingly in the first Mitsubishi evo's - they retarded spark so much at lower revs that the fuel was burnt way past the exhaust valve open and that enabled the very large fixed geometry turbo to be kept awake and ready.

The smoke is a result of the fuel not being completely burnt, partially due to the direct injection system being less able to mix the air and fuel than an indirect system.

It is true that there is an additional quantity of fuel injected to create exhaust gas expansion but this doesn't continue to burn after the exhaust valve is opened on a diesel.
I would be very surprised if the amount of fuel injected ever went past the stoichiometric ratio.

 

[Dieselman]

Sorry guys havent been on the forum lately been busy.
but anyways my C270 CDI is blowing puff of black smoke when you step on it (full theottle). Is this normal?
The engine was serviced about 5000km ago. New air, fuel and Oil filters were installed. Using Mobil synthetics and Shell Diesel . Let me know.

Regards,

Yudy

Re reading your post I would say the smoke is a result of the high sulpher content in your fuel.

 

[eurico]

The smoke is a result of the fuel not being completely burnt, partially due to the direct injection system being less able to mix the air and fuel than an indirect system.

It is true that there is an additional quantity of fuel injected to create exhaust gas expansion but this doesn't continue to burn after the exhaust valve is opened on a diesel.
I would be very surprised if the amount of fuel injected ever went past the stoichiometric ratio.

Yes it does if it's deliberatly injected late as to burn in the exhaust manifold. This is done in DPF equiped cars where a little droplet of fuel injected when the exhaust valve is fully open to increase temperature in filter's honeycomb in order to burn the soot when low load/temperature is present. Modern common rail Diesel have very low enthalpy in the exhaust gas and turbo's are run by enthalpy. The only way to get them to run quickly is to rapidly increase said enthalpy - burn fuel later for the exhaust gas not to loose temperature and pressure = enthalpy. In Diesel engine stoichiometry does'nt make much sense as they are always running with different ratios of excess air and a stoicheometric ratio means all the oxigen is consumed by all the fuel. Also, Deiselman, there's no air mixing with fuel in any Diesel injection system. You have a cylinder filled with air that almost in the end of the compression stroke is injected with fuel by a high pressure system. The difference between direct and indirect systems is that the latter uses a pre-cumbustion chamber. Technically they are both direct injection systems but one uses a pre-chamber. Both only inject pure fuel - no air mixing anywhere.

 

[stasis]

well like i said in the first post. air,oil and fuel filters are barely used for about 5k km now. e car in to repl
Dieselman i dont use the high sulphur fuel which is sold by the state owned fuel company (pertamina). I used Shell Diesel imported from the reifinery in Singapore.
After the car got serviced it didnt blow much smoke until now. Power seemd to be allright. Wait i remember something now. I had to replace the gasket at the turbo inlet manifold the other day and replace the outlet gasket too. Replace the clips that clips the turbo assy and the manifoldas well. After changing the turbo inlet gasket the car seems to be more responsive though. I gues the turbo doesnt lose the pressure through the leakage

Could this be realted some how?!

 

[Dieselman]

Yes it does if it's deliberatly injected late as to burn in the exhaust manifold. This is done in DPF equiped cars where a little droplet of fuel injected when the exhaust valve is fully open to increase temperature in filter's honeycomb in order to burn the soot when low load/temperature is present.

I know that, but that wasn't the issue you were talking about. You said it was to spool the turbo up.
The particulate trap regeneration only takes place very infrequently, once the filter is full.

Modern common rail Diesel have very low enthalpy in the exhaust gas and turbo's are run by enthalpy. The only way to get them to run quickly is to rapidly increase said enthalpy - burn fuel later for the exhaust gas not to loose temperature and pressure = enthalpy.

The load on the engine does this as more fuel is burned to create torque so the more the gas expands. there is no requirement for additional expansion.

In Diesel engine stoichiometry does'nt make much sense as they are always running with different ratios of excess air and a stoicheometric ratio means all the oxigen is consumed by all the fuel.

Still, when the mixture reaches 14.5:1 it is stoichiometric. This is peak torque output.

Also, Deiselman, there's no air mixing with fuel in any Diesel injection system. You have a cylinder filled with air that almost in the end of the compression stroke is injected with fuel by a high pressure system. The difference between direct and indirect systems is that the latter uses a pre-cumbustion chamber. Technically they are both direct injection systems but one uses a pre-chamber. Both only inject pure fuel - no air mixing anywhere.

The air and fuel certainly DO MIX otherwise they wouldn't burn. The mixing takes place inside the cylinder courtesy of high velocity swirling of the air.

In the indirect system this takes place in the SWIRL chamber and in a direct system it happens in the main cylinder chamber as a result of the bowl in the crown of the piston causing a rapid vortex as the piston rises.