Hello dier friends!

First big problem after 15 years trouble free!

My Sup(2.5 tdi) today start to show black smoke when Im acceleratiing hard(above 4000 rpm).

It doesnt have any other simptoms like higher fuel useage or losing power.

I must admit I drive it slowly last 3-4 monts because road in my route is under construction, and this could be problem from past months, I dont know but today I drove slighty faster then usual, and got black smoke.

Could someone help me what can be cause, and what to look for and where to start?

Did someone had this kind of issue ?

Black is usually unburnt or poorly burnt fuel. When was it last serviced and was the air filter replaced. That or too much fuel being injected into the cylinders. If it was the rings or valve quides that would probably be a more blue ish colour.

Others will hopefully be along with a more defined answer.

Good luck.

Thanks for reply. I didnt expect just one member to reply to this problem, but obviously it is uncommon problem.

Tommorow I will try to read errors with vcds light, if I could.

I did notice today, black smoke happen just when engine is hot, there isnt black smoke, when engine is cold...

Any boost leaks will cause black smoke also, so worth a look round the engine bay to look for anything obvious

When the engine is cold it use's more fuel, naturally. Maybe when it is up to temp it is not reducing that fuel delivery volume. A poor guess perhaps as I don't know.

 

SuperbTWM, kindly perhaps be more specific. Do you mean as in exhaust leaks, air leaks  or both. I don't know just trying to help MilanM to gain some idea.

Replace the air filter, clean the MAF sensor and see if that improves it. As Suoerb said above a split in one of the boost pipes or a lose clamp can cause loss of boost , which creates over fuelling. Splits tend to happen after the intercooler and don’t normally show  until under pressure. 

46 minutes ago, Danny 57 said:

SuperbTWM, kindly perhaps be more specific. Do you mean as in exhaust leaks, air leaks  or both. I don't know just trying to help MilanM to gain some idea.

 

Boost leaks are leaks between the turbo discharge and the throttle body. The air is metered so the the required amount of fuel can be added. If metered air gets out the car will run rich hence the black smoke. You can usually hear them as well if they are bad but if its only smoking a bit then it could just be a small rip in a hose.

 

Of course it could be many other things but it costs nothing to look in the engine bay and examine.

Edited 7 November, 20187 yr by SuperbTWM

I will try and investigate more thoroughly ...however I did notice some shhhhhh noise when I drove 130 in fifth gear yesterday on motor way.

I have ordered new air filter. Old one was very dusty and filthy.

But Im affraid that it wont be that easy....oh men I just love this car, and it is very hard for me to go through this...i hope so, it will be good as it was, once I find out problem...:(

Thank you guys for helping <3

Edited 8 November, 20187 yr by MilanM

Today she didnt smoke at all...and I was drove pretty fast.

Will try find out whats happening, and I will follow her closly in next few days.

Hopefully just the air filter then.