Black Smoke - Help & Advice needed

[sanj2000]

Hi All

Really hope one of you are able to help


This is the situation, black smoke coming out of the exhaust upon accelerating and moving off from a stationary position. The engine management light will appear after few day of it being reset by a family friend look at the car who is also a mechaninc.


Work undertken so far:


*MAF changed follwing the respective code being reportd on the computer the mechaninc has: P0101/000257 - Mass Air Flow Sensor (G70): Implausible Signal
*EGR valve cleaned (not removed)
*Turbo cleaned (not removed)
*Diesel addative run through car in an attempt to clean up
*Pressure test carried out - no leaks


I am not sure the diagnostic computer he has but it cost him approx £2k it cover all modern car. He did a full diagnostic scan and picked up all the historic error codes.


Once the engine managment light is cleared a few day later it reappears with the MAF error code. The MAF has been changed twice as the dealer agreed to swap out due to the same error code but to no avail.
Initially I had a severe loss of power but following a MAF change and some additional software updated the power is back and turbo is behaving as expected.




Fuel consumption is dropped drastically to approx 36mpg so really need to get this sorted as it has been going on for a few weeks now.


Any help appreciated as to next steps, please let me know if you require any further information.


Thanks in advance

 

[@udi A3]

Any boost leaks? does it run better with AFM unplugged?

 

[sanj2000]

How can you check for boost leaks?
Not tried it without the MAF....will do this tomorrow

 

[hades-]

is the maf oem or aftermarket ?

 

[sanj2000]

Bez i'll need to check but I think it was OEM

 

[darysas]

How can you check for boost leaks

check oul connection from turbo to intake manifold, (oul pipes tubes intercoler) often where is leak there is lot of dirt oil.
black smoke is reason that engine is not enough air.

 

[sanj2000]

apologies for the delay, but wanted to run without the MAF for a few days. There is less smoke with the MAF taken off, and the overall running of the car appears to be smoother. MPG is still the same around 35-36 but guess this is due to the lack of MAF. One other thing I have noticed is that the car take longer to get to temperature and not blowing in hot air with the heating on appreciate that this may be due to the colder weather of late....but thought I would mention.

 

[Andy27168]

I have had similar issues with my TDI engine slow to get to temp, I would check the EGR is clean by removing it, and clean out the pipe work from the EGR back into the intake, as this was totally blocked solid on mine, once this pipework was clean the engine warmed up noticeably quicker. Though there is an underlying problem with mine as I have three knackered injectors which I believe is what is coking up the pipework. Your problem could be faulty/dirty injectors.