2.5 TDIlong-startup + exhaust cloud

[propeller]

Hi. 

I have 2.5TDI  120kw 2006 superb. Now when the winter is coming and it starts to get around 0 degrees outside my superb has a long startup time + exhaust cloud when its finally fires up. I have noticed that those symptoms appear only when its  0 degrees or less outside. Last winter i changed glow plugs and diesel filter hoping it helps for this problem. Actually it felt that that maybe it did help for some time , or maybe i was imagining it.... anyways its back .

I had my car unused for a week outside (about -3 degrees) and i had to run the starter for about 4-6 seconds before it started up. i thought that maybe its because it were unused for a week, but even now when iv been driving with it regulary to work/ shop etc. the startup in the morning is not that bad but still around 3-4 seconds. 

Where to start ? what to check? anyone has same problem? is it even a problem? 

 

Thank you for any helpful replys.

[iob]

Best place to start would be a scan for errors with the VCDS. If done already or no errors stored, I would have a look in this thread: http://www.briskoda.net/forums/topic/340266-25-tdi-cold-starting/page-3?hl=%2Bcold+%2Bstart#entry4136817 , as myself and other members had similar issues, maybe one of the solutions mentioned there might be an answer to your problem...

 

I have tried the cheap ones (changing Glow Plugs, "T" from the fuel filter, checking the G62 sensor), but I stopped before the more expensive ones like changing the injector nozzles, as I could live with a rough start as long as our winters are not as long/harsh as yours... It's up to you how far you are prepared to go for such an issue, as with the age of the car some issues are bound to appear.

[dieselV6]

Check/replace glow plugs and on warm engine, easiest way to check first is with a clamp DC Ampmeter over entire glow plug feed, on a cold day when you first turn ignition on, that will tell you how much current they take and also will show if the glow plug relay is playing up.

 

If GPs definitely work, check engine injection timing with VCDS, a good value for the 2.5TDIs is 0degATDC -1.0 deg ATDC, though for some reason Skoda insists on quoting 0.8ATDC to 2.7ATDC.  I had 1.7ATDC from factory  and had poor cold starts for a year before I adjusted it, nowadays I run about 0.5-0.7ATDC.

Injection timing can be adjusted on engine, only timing belt cover needs to be removed, 3 bolts loosened, belt slightly moved and the 3 bolts retightened. HTH

Edited 28 November, 2015 by dieselV6