Black / Grey smoke 2.0 tdi A4

[Blue Smoke]

Hi guys,

Hope you can help me with a problem that has been bugging me for a while on the audi A4 2.0 tdi 55 plate blb engine code.

Ive been getting a small amount of white smoke on cold startup and large amounts of black/grey smoke on aceleration, The car also has a bit of vibration in the seats...like a small judder at idle, idle's fine btw and does not miss and is not rough.

It doesnt smoke when cruising it smokes after slowing down and pulling away again.

Noticed its all or nothing on the turbo on pulling away, it will accelerate slowly until about 2000 rpm then whacks you back in the seat as turbo kicks in or is that normal?

Check emission light came on and vag reader said it was faulty MAF, code P0101 and cylinder 4 glow plug circuit p0674

We replaced the maf but still smoked exactly the samee and after 80 miles check emission light is back on with fault P0101 and im not sure where to turn next, Clean EGR valve maybe?

Want to add that there is a rattle from the engine but it is the aircon clutch so have ruled out DMF for the engine vibration/shudder.

Just worried it could be something serious and want to get it fixed before it got worse/ruined something.

Many thanks for looking and any help is greatly appreciated.

EDIT: Forgot to add it has just had a full service so all filters are new.

[Crasher]

Why did you buy the Air Mass Meter from?

[Blue Smoke]

Maf is a genuine Bosch one from a bosch service dept.

Also two new updates we found today:

1, Maf fault was different this time, it was p0101 range/performance...now its p0101 implausible signal

2, Noticed oily black sludge at the bottom of the big hose that connects to the Maf

3, Oil cap is letting by oil and welling up ( only small amounts) and it puffs smoke with cap off, also big hiss when cap removed....still has suction on a hankerchief placed over it though

Could a blocked crankcase breather hose or filter cause this maf fault and smoke?

Thanks again guys for looking, Its a great help.

[Crasher]

Fit a genuine Audi dealer supplied AMM and see what happens. If it cures the fault, give it back to Bosch and insist that they give you your old one back or they pay the Audi surcharge. This is a problem we experience all the time with Bosch exchange AMM’s.

[Blue Smoke]

Hmmm the one we took off was a bosch so presumed it was the original and replaced like for like

[Crasher]

Yes and so is the VAG dealer supplied one but they come from different plants.

[Blue Smoke]

Ok im confused now

Audi are saying i have the correct one on there, Part No: 074906461 BX

[Crasher]

But you didn't buy it from Audi did you?

[Blue Smoke]

I dont think so Crasher, my mechanic got it for me but he made me aware it had to be an original one.

Out of curiosity what is the differance between them, i know you said they come from different plants but is there some key differance why they wouldnt work even though they have the same Part No.

Cheers for the help so far mate.

[Crasher]

All I know is that Bosch boxed AMM’s have caused myself and others huge problems whereas genuine VAG dealer supplied ones don’t.