Golf BKD smoky

[pjgt-tdi]

Looking for a bit of help with this one please. My 2005 gt tdi with 63000 miles has recently become quite smoky, literally overnight. It doesnt seem to be down on power and its also doing a lot better mpg, it has gone from doing 50 mpg to 60 mpg on a mixture of short/long journeys and from 60mpg to 70 mpg on long journeys. The black smoke is only there when i accelerate but its quite excessive and it hadnt been producing any smoke before on acceleration.

[Crasher]

Probably a boost leak, check the hose into the anti shudder flap at the front of the engine, they often blow off at one side due to wear of the barbs on the hose.

[phil miller]

Looking for a bit of help with this one please. My 2005 gt tdi with 63000 miles has recently become quite smoky, literally overnight. It doesnt seem to be down on power and its also doing a lot better mpg, it has gone from doing 50 mpg to 60 mpg on a mixture of short/long journeys and from 60mpg to 70 mpg on long journeys. The black smoke is only there when i accelerate but its quite excessive and it hadnt been producing any smoke before on acceleration.

when you find out whats wrong post it up so i can do it to mine, id love to get 50-60 mpg mix, i struggle to get 53 if i drive like an old woman

[pjgt-tdi]

thanks crasher, i'll have a look at that. do the egr valves give much trouble on those golf's??

[Crasher]

The EGR valves often leak oil that has come through the system as vapour from the breather system and slight loss from the turbo (which is quite normal) and this looks unsightly but is not a valid cause for replacement. Sometimes the EGR valves fail and often they become extremely blocked with soot from the exhaust fumes which mixes with the oil vapour, forming a disgusting thick tar like goo which is evil to clean out. If you have to pay someone to clean out the valve, it is more sensible to just fit a new one, if you can clean it yourself, get out the thick gloves, goggles, paint striper, oven cleaner, thinners, plastic scraper and get scrubbing, ohh and take a good shower after…

[pjgt-tdi]

hi crasher, thanks for all your help so far. when you say the anti shudder flap , i presume you mean the inlet manifold flap under the egr valve?? couldnt find any hoses disconnected, cut or collapsed. took the car to a friend who plugged into it. there was no emissions light on the dash by the way. anyway it brought up a fault saying fan movement restricted, he erased it but still the same problem. i saw on other threads how the rad fan and manifold flap are sort of related by a fuse but this fuse isnt blown on mine. will take off egr and the flap underneath it tomorrow and give them both a good clean and see is there any difference.

[nevo]

Wow 60 mpg out of a bkd,thats a rare one! is the black smoke visible out of the rearview when you floor it? I would of thought your mpg would drop if its a boost leak,anyway check all the boost pipes including the intercooler,wont do any harm cleaning the egr thats one eliminated.

[pjgt-tdi]

i uploaded a picture of the current mpg with egr not sorted, still a bit smoke , not too bad , great mpg and no loss in power.