Black smoke when accelerating gently from low revs, no power loss. computer showing good mpg. really quick for a 115 bhp. any ideas

SOURCE: 2006 VW tdi black smoke while accelerating

Hi
The only sensible way forward is to get a list of fault codes from the onboard diagnostic system and take it from there. You could either go to a VW dealer, or if you are technically minded you could buy a £15 interface cable, download some free "VAG diagnostic software" and run it on a portable computer.
There are lots of possible reasons for the problem and guessing will not really help. If these suggestions turn out to be sound, please give my reply a "Fixya!"rating, If they do not, please hold off rating and add a comment with more details so I can try to help you further. Cheers, D

SOURCE: 2001 Mercedes E220 CDI exhaust black smoke on acceleration

hello,according to service information;smoke formation or si 07.16-p-0004a (service inform) from mb ,your engine have normal function,if you want ,ask your dealer about the service inform with number 07.16-p-0004a,you can read the explanation regarding your problem,ty

SOURCE: Diesel smoking and lack of power

on my sorento same problem and its solved vacuum pump on turbo, now ok, sorry for bad english, vacuum membrane is broken

SOURCE: Citroen 2.0 Hdi surging and black smoke

which is standard or the best motor oil for HDI?

SOURCE: Fiat Stilo 1.9JTD power loss after 30k miles

Its the EGR valve. Had exactly the same problems on my old 1.9 JTD.

You can take it off and remove all the carbon crud thats built up inside but the problem WILL return unfortunately. Its a mechanical failure so no error codes will be shown for this fault. You can also block them off which will return all of your power but also possibly make it an MOT failure due to excess soot coming from the exhaust.