It's back again. Grrrr

[danb986]

About 6 months ago I had a problem where my car would put out a cloud of light grey/blue smoke every time I pulled away from idling.
At the time I cleaned the egr, all the intercooler pipes, checked the turbo and took out some oil as Audi had filled it to just over the max mark.
About a week after doing all this it just stopped by itself and has been fine since then.
Then, about a month ago I was getting a cloud of grey diesel smoke on cold start up and it was a little lumpy for about 2 seconds, but I put this down to the very cold weather. Just to be sure, I put a double dose of Millers Diesel treatment in with a full tank of Shell V-power. Shortly after this the weather changed and my start-up smoke totally vanished, only to be replaced with my old problem of smoking when I pull away.

I'm lost now. It can't be anything like turbo, valve stem seals or tandem pump otherwise it wouldn't have sorted itself out last time and been perfect for 6 months.
I've ran a VCDS scan and found no faults. I then checked the injector readings with VCDS and got the results below, which I believe are acceptable:

Inj 1 - 0.00
Inj 2 - 0.35
Inj 3 - 0.30
Inj 4 - 0.00

Has anyone got any ideas why the smoking has returned? At the service when they overfilled the oil I'd also had a new sump fitted, so I'm wondering if something is wrong and the dipstick might be reading wrong. I'd just topped up the oil before the smoke started again, but only 2/3 of the way between min and max because I'm nervous of overfilling it.
It doesn't seem to be using oil any more than normal and the coolant level never moves.

Help me please!
I want to sell the car and get an A3 black edition, but nobody will buy it with it smoking like this.

 

[danb986]

After a lot of searching and thinking, I've seen mentioned about changing the temperature sensor.
Does anyone know what sensor they mean and where it's mounted?
The temperature gauge reads normal, but is there another sensor that would have an effect on fuelling or something?

 

[max69vk]

Is the car remapped or standard?

 

[danb986]

Is the car remapped or standard?

It's just bog standard.

 

[TDI140]

Overfilling oil will damaged your cat causing oil to sit in the exhaust and cat so your car will smoke until the exhaust is clear and sorry to say your cat could be knackered now if its got oil in it and smoke will be normal

 

[danb986]

Overfilling oil will damaged your cat causing oil to sit in the exhaust and cat so your car will smoke until the exhaust is clear and sorry to say your cat could be knackered now if its got oil in it and smoke will be normal

It was only about 3mm above max when Audi gave it back to me and I removed most of it quite quickly. Surely if my cat was full of oil and knackered then I would've thought it'd smoke all the time, rather than stop for 6 months and then come back again. Wouldn't it smoke all the time or would it just happen when I pull away from idling?

 

[TDI140]

Yes it would smoke all the time if oil was sitting in the cat

 

[danb986]

Well at least I can rule that out. Being smoke free for 6 months and then only getting it after idling for a while doesn't sound like the cat's oily.

 

[danb986]

Just been thinking, the smoke started about 75 miles after filling up with Shell V-Power and a double dose of Millers Diesel Power Ecomax (to try to get rid of the start-up smoke, which it did).
The Millers stuff says use within 12 months of opening. I can't remember when I bought this bottle, but if it was out of date then would this cause smoke?
I've emailed Millers, but not had a reply yet.
I'm trying to use up the rest of the tank of fuel so I can fill it up with a fresh tank from BP, but for once this tank seems to be lasting forever!
I can't for the life of me remember if I'd used this stuff last time I had the smoke problem.