Black smoke on acceleration

[rburnham11]

Hi all.

My viano has had problems for a while now. It smokes heavily under acceleration.
It's fumey on idle but under acceleration of over half way pressed pedal it chucks out lots and lots of black smoke.
it's been to a few garages but no Merc specialists yet.
I know it has a slight leak in a intercooler pipe but garage thinks this isn't enough to cause the amount of smoke.
I have changed various bits, injectors, air filter, ect.

so question is, is there any chance the fuel pressure is too high somehow? I'm thinking it's an electrical problem of some sort.
should mention it has no codes.

I do plan for it to go to a specialist but it's in constant use at the moment and it drives fine, just smokey.

any advice would be appreciated.
cheers
Rich

 

[Bellow]

I know it has a slight leak in a intercooler pipe

That needs fixing anyway so why not now and see if the problem still exists once it's sorted?

 

[design guru]

A leak in the pipe can cause black smoke on acceleration, more likely is the actual intercooler could have a leak

 

[amgv12power]

Good shout

 

[rburnham11]

so this is still not sorted, it did go to a merc specialist who said i had a fuel leak and tightened it up and sent me on my way (after an excessive bill for doing so) and still smoking just as bad.
so here's where its at.

I believe it has a fair few electrical problems. The main issue is when accelerating over half pedal press in chucks out a lot of black smoke, many things have been done to try to eliminate this such as air filter, sensors, injectors, new intercooler and pipework yet it still persists. I have numerous other little electrical issues so am starting to think they all may be connected. the re-circulation button doesn't work, the AC has just had new condenser and gassed up and sometimes it works and sometimes it doesn't. I regularly get warning messages displayed about various bulbs not working but they always are on the left side of the van. the blowers on the left side of the van are also noticeably less effective than the right side. The electric doors used to work fine now both are not working at all.
It has an engine light on now which never used to be on, it says o2 sensor related, this has been changed and still on.
the van drives well albeit smokey and probably less fuel efficient than it should be.

 

[m80]

1st port for the electrical issues is battery voltage.
Pull the 2 electric door fuses, that often resets them after a low voltage drop out.
If the SAM has seen moisture it will cause problems. The under bonnet fuse enclosure can fall victim to poor sealing and / or drainage issues. There's a lot of electronics in there.
But if issues are common to the left look for common grounding points, loose or corroded.

You've, I assume, eliminated the intercooler route for your excess smoke.
Were they 'new' injectors? Were the new codes entered into the ECU?
Were the injector adaptations carried out?
If enough miles are covered I believe matching of the injectors is done by the ECU, maybe others with greater knowledge can confirm.

Otherwise for the smoke look at oil passing the turbo, or a duff PCV valve.
Beyond those you need to see if there is oil passing at the bores, the engine being worn. Or simply the valve seals passing.

You don't say which engine.
Many Viano's have been a taxi in previous life, with associated corrupted mileage, I was caught by that one.

 

[rburnham11]

Thanks for the reply
the doors have stopped working in the past, usually one at a time so i have disconnected the battery previously and that usually sorts the doors for a while. This time they have stopped all together, haven't tried disconnecting yet.
my previous van had issues with the sam unit so I know it's a point of potential faults and is what I am suspecting it to be.
Would a duff sam unit cause excessive fuelling?
I would say the intercooler and pipe work can't be the issue anymore so I would like to think I have ruled that out.
The injectors were changed because of this excessive smoking and it's exactly the same before the injectors were changed and after. They were reconditioned injectors and I believe they were the ones I took out that were reconditioned then reinstalled. they were recoded after installation too. I have done thousands of miles since and have just learned not to accelerate over half way or the death cloud comes out.
What injector adaptations do you mean?
I don't think it's oil related as it's clearly too much fuel rather than oil being burnt.
it is an 11 plate 2.2 viano. it does have high mileage but it does drive nice

 

[m80]

Most likely you have the om651. Unless you have a late 646, but that's less likely.

The SAM wouldn't affect fueling, although the ECU and TCU are in the same enclosure.
Personally I wouldn't expect rail pressure to be an issue. But with the Torque app on an Android you could monitor that live as you drive.

My comment regarding many miles 'may' negate the need for coding / adaptations, as the ECU could well self learn. But as said, others may have better input on that.
Anyway, I also believe, that post refurb the injector coding is lost.

Personally I wouldn't go down the refurb route again. My only experience was a bad one. When I bought new they weren't so much extra ££'s anyway.

Tickover and running adaptations are caried out on Star / DAB.

Diesels can run to destruction on engine oil, so for me eliminating that makes sense.
I imagine you are experiencing regens often. That would effect consumption some.

Try pulling 27 & 28 on F34 for the doors to reset.

SAMs are plug and play, a good 2nd hand unit will do the job if needed.

 

[Tonye]

Diesels can run to destruction on engine oil, so for me eliminating that makes sense.

I would be getting a compression test done ASAP. Is it over full with oil, have you checked it at least once a week to monitor it dropping. As m80 said it will destroy itself if it runs away and you can't stall it.

 

[Bellow]

it chucks out lots and lots of black smoke.

Fuel burns black, engine oil burns blue.

Rich

It's emulating your name.... either over-fuelling or starved of air.

 

[rburnham11]

its definitely heavy thick black smoke and smells overly fuelly too. i dont think its oil, if it was oil id be putting oil in at alarming rates but its not the case. however i have noticed my mpg drop considerably since the black smoke started.
i have changed all intercooler pipes and air filter, how else could air be restricted? unless its turbo related.
over fuelling, what would cause this?

it is going in to mercedes on friday so hopefully they will find out the issue, hopefully. I will update when I know.

 

[Bellow]

its definitely heavy thick black smoke and smells overly fuelly too. i dont think its oil, if it was oil id be putting oil in at alarming rates but its not the case. however i have noticed my mpg drop considerably since the black smoke started.

As close to 100% certainty that the smoke is from fuel not engine oil as is possible.

i have changed all intercooler pipes and air filter, how else could air be restricted? unless its turbo related.
over fuelling, what would cause this?

If overfuelling is the problem, your garage visit tomorrow should provide an answer. If air starved then probably turbo related (which I doubt) or some blockage. It wouldn't be the first time a stray plastic carrier bag (or the like) entered the air inlet and partially blocked it upstream of the filter.

it is going in to mercedes on friday so hopefully they will find out the issue, hopefully. I will update when I know.

You will know more by close of play tomorrow.

 

[markjay]

Leaking injectors is another cause for overfuelling. As is blocked air filter. Or (less likely) clogged inlet valves. That been said, with modern Diesel angines, there are many other electric (sensors) and electro-mechanical (actuators) elements that can malfunction, MB STAR diagnostics is a must.

 

[ALFAitalia]

On most modern cars a blockage wont affect fuelling......the ECU will soon pick that up on its sensors and reduce fuelling and therefore power to compensate. A missed air leak is the usual cause in my experience. I had my rear bumper getting black with soot for apparently no reason. I looked many times for the leak...in the end I get under the car whilst my son revved it to reveal a 1 inch split in the intercooler outlet pipe...which was invisible and near enough sealed at idle. £90 later (FOR A 12 INCH RUBBER PIPE!)....sorted.

 

[rburnham11]

So latest update.
It went to mercedes. they changed the injectors because apparently they were not oem standard, they were reconditioned injectors though and ran fine. after new injectors installed it was exactly the same. had some work done on the AC too and at a bill of £3.5k I got the van back, still black smoke and AC not running still. not best pleased. basically they are saying the van is not giving any codes so there is nothing they can do. they believe the black smoke is dirty exhaust.
the AC all mechanically works however but i believe it has electrical issue as when you press the ac button sometimes it works sometimes it doesnt, most the time it doesnt! has anybody got a electrical diagram that runs the ac please? it could be as simple as a dodgy relay. but i dont want to spend more with them as they have enough of my money for not fixing the problems as it is! the whole control panel clicks when plugged into a code reader. what supplies this panel?
cheers
Rich

 

[pcthrillrider2]

i had lots of black smoke under full throttle on my C200cdi w203 but a bottle of wynns extreme diesel cleaner sorted it in 11 miles!

 

[m80]

So latest update.
It went to mercedes. they changed the injectors because apparently they were not oem standard, they were reconditioned injectors though and ran fine. after new injectors installed it was exactly the same. had some work done on the AC too and at a bill of £3.5k I got the van back, still black smoke and AC not running still. not best pleased. basically they are saying the van is not giving any codes so there is nothing they can do. they believe the black smoke is dirty exhaust.
the AC all mechanically works however but i believe it has electrical issue as when you press the ac button sometimes it works sometimes it doesnt, most the time it doesnt! has anybody got a electrical diagram that runs the ac please? it could be as simple as a dodgy relay. but i dont want to spend more with them as they have enough of my money for not fixing the problems as it is! the whole control panel clicks when plugged into a code reader. what supplies this panel?
cheers
Rich

I don't see that an MB agent would fail to identify the AC.
Initiated they would see the increase in pressure on DAB / Star.
If no increase they could initiate via Star. That would, imo, then point to dash control or SAM.

I'm pretty sure iCarsoft could do this. Maybe someone else could confirm. If so it may well be worth your investment.

The dash control is on the canbus, that communicates with the SAM.

A thought, has your ECU been mapped, badly.

 

[marko1]

Have you checked to see if the dpf has been removed because if it has then the soot would not be collected, and after all that is what it is for.