I recently bought a 2007 Octavia Mk2 1.9TDI PD 105hp with a DSG box. The car has done 103k kms. It emits black smoke at any sort of acceleration - at aggresive throttle inputs it smokes real bad. It also feels underpowered nad now there is a slight whistle from the turbo. Its not a 'police siren' but the whistle is easily noticeable. The car needed servicing at the time I was buying it and I assumed that servicing will help resolve the issue of black smoke et al. Bad assumption. I serviced the car with full synth and all new filters. Problem remains. At that point of time my assumption was kind of justified as I had the car scanned at a dealer and there were no fault codes.

I recently cleaned out the MAF, EGR, manifold, intercooler and the turbo. No change. The exhaust was pressure washed as well. I then took it to the dealer and they first said that the EGR is shot. I got it replaced. No change. I refused to pay for their EGR, and got mine back. The dealer now says the turbo needs to be replaced.

I am assuming it is either the turbo or the injectors or the engine itself. If I can rule out the other 2 - injectors and the engine - then also I will put my money on the turbo straight away. Are there any fool proof tests to dtermine the health of any of these 3 components?

I am based out of India and a new turbo at the dealer is 1200 pound sterling. I am getting new ones outside for 400 pound sterling but they are all Chinese copies. I am willing to import one from Germany - a genuine Garrett one is costing me 500 pound sterling with shipping - IF I know for sure that this is going to solve my problem. Which brings me to the reason why I started this thread - how do I REALLY know that my turbo is shot? Honestly I would much rather sell the car and take a loss rather than continue to replace one part after another.

Sounds normal to me particularly on the 1.9PD. I have one and it plumes out smoke if you haven't accelerated for a while or sat in a lot of traffic.

Premium diesel fuel helps, not sure if you can get it in India or not. If not then try a bottle of diesel additive to clean things out. It needs a good thrash now and again to clean things out. Turbo whistle is normal on these and as long as there isn't a siren you should be ok.

Another possibility is that you have blown a seal somewhere or a boost pipe.

If it was just the smoke I would still try to live with it. However the car does feel underpowered as well. Premium fuel is available in India nad so are plenty of fuel additives. I will dump a bottle in the fueltank and then see. Re. boost pipe - I have observed the N75 pipe going to the turbo and that seems fine. What other seals and pipes i should be checking?

Edited 27 June, 201213 yr by Pravs

sounds like you have a turbo pipe leak somewhere to me

sounds like you have a turbo pipe leak somewhere to me

The same question then - where should I be looking for a leak?

anywhere from turbo to intercooler to engine, there is a mix of hard and silicone pipes and joints, check joints first and look for cracks etc

mine has a lovely whistle

Edited 27 June, 201213 yr by Lofty79

i had a symptoms like this with my pd fabia,it turned out to be a faulty maf

a yes you only cleaned the MAF this is first thing to change usually

Not absoulty sure, but if your turbo was that shot, to the point that it needed replacing, the first sure sign would be a serious loss of power, not sure if there would be smoke like you describe but a loss of power would be very noticeable indeed, I'm sure there will somebody on here will know....

Edited 27 June, 201213 yr by studmuffin

New MAF would be my guess too. Cleaning them often doesn't do any good in my experience.

Black smoke doesn't sound like a problem with the turbo itself.

Not absoulty sure, but if your turbo was that shot, to the point that it needed replacing, the first sure sign would be a serious loss of power, not sure if there would be smoke like you describe but a loss of power would be very noticeable indeed, I'm sure there will somebody on here will know....

If the turbo is shot then the engine would be getting less oxygen than it needs (compressed air = more O2). This would show itself as over fuelling and lots of unburnt diesel, black smoke in other words.

A duff MAF would also manifest itself in this way as the ECU would think its getting more air than it actually is and put more fuel in causing incomplete combustion and black smoke. An air leak is also a possibility.

If you want to go down the route of swapping parts until you find a cure then start with the MAF as its a lot cheaper. I would suggest you get the MAF tested and see what they say first though.

If the turbo is shot then the engine would be getting less oxygen than it needs (compressed air = more O2). This would show itself as over fuelling and lots of unburnt diesel, black smoke in other words.

In theory perhaps, but ECUs are pretty good at adjusting for this. Lack of boost from the turbo will be picked up by the MAP sensor, the ECU will turn the fuelling right down, the car will feel gutless, but there will be little or no smoke from the exhaust. I've had intercooler pipes fall off and wastegates stick open on a few turbo diesels and very rarely does it result in any exhaust smoke at all, just extreme lack of power.

I think the black smoke suggests the turbo is actually fine and the fault lies elsewhere.

Thanks for your replies.

Before I cleaned out everything the car would feel underpowered in lower gears but would easily climb gradients and go above 100kmph without issues (except the black smoke that is). After I cleaned out everything it is finding it tough to go past 100. Moreover if I accelerate hard at standstill the car tends to choke after emitting a lot of black smoke and the engine shuts down.

I will check the hoses and see if I can swap my MAF. When you really need the ECU to tell you whats going on the stupid thing will not even show a fault code.

When I had the turbo out I found very little play in the turbine assembly. If the bearing of the turbo hardens can that result in these kind of issues?

The turbo should have very little play in the shaft, but should spin freely.

If you could borrow a known good MAF to swap temporarily that would at least prove/disprove the MAF as being the cause.

Nick - Like I said there is very little play. The spinning freely part is something I am not to sure of. There is a small metal ring on one side of the CHRA and that is sometimes preventing the turbo from spinning freely. I really can't open the CHRA and swap that ring.

The pipes were all checked yesterday for a leak. None found.

Like you said, I am now looking for somebody with whom I can swap my MAF.