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Hello,
I have got a problem with my G4 1.9 tdi 81kw. When the motor is switched off for longer than 10 hours, it started to smoke white after the startup. The motor is also shaking. The problem is gone when i move the car. I changed the injectors, glow plugs and the turbo is also new. Vacuum hoses are new too. So these things should be ok. The fuel line is clear without any air bubbles.And the display in the car after cold startup showing strange values (about 51 l/100km). There is the video of the cold startup :
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Thanks for any advices! And sorry for my english, im trying my best :D
 

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Hi Kubayz3, white smoke is excess unburned fuel. Were the injectors change before or after the problem? Did it start happening shortly after your last fuel fill up?
 

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The smoke you are seeing may be from leaking valve stem seals. While the engine sits, the stem seals cool down and shrink. Dirty oil and wear makes the clearance between the seal and the valve stem just large enough to leak oil into the engine combustion chamber. Engine oil doesn’t burn as well as diesel, which is why you have rough starts and everything works out, once the oil is burned out of the combustion chamber.
 

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Discussion Starter #6
The smoke you are seeing may be from leaking valve stem seals. While the engine sits, the stem seals cool down and shrink. Dirty oil and wear makes the clearance between the seal and the valve stem just large enough to leak oil into the engine combustion chamber. Engine oil doesn’t burn as well as diesel, which is why you have rough starts and everything works out, once the oil is burned out of the combustion chamber.
I understand what you mean. But the smoke can come out even for few minutes but never comes out all. I have to always drive the car and heat it just a little bit to get rid of the smoke. And the smoke is fully white not blue or black and sometimes smokes more than what is showed in the video.
 

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I see. White smoke like your describing is condensation or water. Could be condensation in the exhaust that is being heated and burned off (normal), which is more noticeable in colder months...
Or it might be more serious, like water entering the combustion chamber by a leaking head gasket or a crack in the head.
Your headline says ‘white diesel smoke’... did you smell this smoke and it has an order of diesel?
 

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Just watched your video... looks like it’s burning engine oil. If you tell me that it smells like diesel, then I agree with Moonshot. Your next step is to check for a dead cylinder by a compression test. If that fails to meet specification, a leak down test would tell you where the leak is, without tear down.
 

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Discussion Starter #9
I see. White smoke like your describing is condensation or water. Could be condensation in the exhaust that is being heated and burned off (normal), which is more noticeable in colder months...
Or it might be more serious, like water entering the combustion chamber by a leaking head gasket or a crack in the head.
Your headline says ‘white diesel smoke’... did you smell this smoke and it has an order of diesel?
Yeah, it smells like old diesel truck :D and there is one thing what I didn’t wrote , the car smokes also in summer times. As I wrote the water level is stable and the G12 compound is clear withou any oil.
 

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Well my TDI friend... from what you described and the roughness of the engine I now see (in the video) looks like you need a compression test to check for a dead cylinder.
 

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Are you sure abou that? :( the car is starting absolutely awesome also in the coldest weather (about -10). And driving is also allright without any loose of power.
 

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You car has a mechanical injector pump that could be over fueling.

What I am sure of is that raw diesel fuel is coming out your exhaust because of incomplete or no combustion and the engine idle is rough. The rest is trouble shooting and testing. If the cylinder is over fueled or it doesn’t have compression, it won’t combust.
 

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One thing I haven't seen mentioned is when this problem began. Has it been Summers ago?.. one fill-up ago?... or yesterday etc. The onset can sometimes be a clue. If you say from last fill-up... I would say bad tank of fuel (water and diesel smoke mix is in the vid). If it's been a long while ago and has increased slowly over time I would say maybe bad valve guides. If you have access to a Vag-Com the injector information should show if an injector is over fueling.
 

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Discussion Starter #15
You car has a mechanical injector pump that could be over fueling.

What I am sure of is that raw diesel fuel is coming out your exhaust because of incomplete or no combustion and the engine idle is rough. The rest is trouble shooting and testing. If the cylinder is over fueled or it doesn’t have compression, it won’t combust.
Yeah, i have some ideas about the injection pump. I found something about n108 valve which can cause the problem but I will test it. I checked the injectors values in vcds in the channel 13(injectors deviation) and the injector 3 was giving strange values(about 2 mg), other injectors was about 0 value. About the pressures in valves... I will test it soon, so after it I will post results here. Thank you!
 

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One thing I haven't seen mentioned is when this problem began. Has it been Summers ago?.. one fill-up ago?... or yesterday etc. The onset can sometimes be a clue. If you say from last fill-up... I would say bad tank of fuel (water and diesel smoke mix is in the vid). If it's been a long while ago and has increased slowly over time I would say maybe bad valve guides. If you have access to a Vag-Com the injector information should show if an injector is over fueling.
I can’t really say, because I already bought the car with this problem :D and as I replied to the post upper. The injector deviation value is strange at injector 3 (about 2mg) Any tips how to solve this? Thanks!
 

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I can’t really say, because I already bought the car with this problem :D and as I replied to the post upper. The injector deviation value is strange at injector 3 (about 2mg) Any tips how to solve this? Thanks!
I think you are on the right path looking at the injector and injector pump to solve the issue. Maybe someone can help you with the specifics who has owned AHL. I have not... just Bew which is completely different injection. good luck!
 

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Discussion Starter #18
You car has a mechanical injector pump that could be over fueling.

What I am sure of is that raw diesel fuel is coming out your exhaust because of incomplete or no combustion and the engine idle is rough. The rest is trouble shooting and testing. If the cylinder is over fueled or it doesn’t have compression, it won’t combust.
So today I measured the pressures in cylinders. Here are the results : cyl. 1: 33.5bar(486psi) cyl. 2: 26bar(377psi), cyl. 3: 34bar (493psi), cyl. 4: 34bar (493psi).
So I think the pressures should be allright. I still have my theory about the injection pump. Isn’t here someone who knows something about bosch VP 37 pump? Thanks
 
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