2005 passat tdi sw backfired after timing belt change

When you say that it lost power, was it restored or did it completely stall and not restart? Who did the timing belt change? There are instruction on this site for how to change it. If there is a parts defect, the tensioner was incorrectly installed, any of the bolts broke, or something dropped into the timing belt, it could cause the timing belt to slip and cause damage to the engine.

More descriptions please. Any other maintenance done at the same time other than what was listed above? Any warning lights or error codes?

timing belt: backfire

Firstly, I incorrectly listed the car as 2005, its a 2004.
The power was not restored, nor did the car stall. A large cloud of grey smoke discharged from the driver's side. The local VW dealership performed the install. I don't have any knowledge of error codes that may or may not have been tripped.

So the car still runs but it's smoky and has very low power? Either the timing belt slipped or a boost hose popped out because they didn't put it back all the way. If the backfire noise was 1 pop it could have been the boost hose popping out. Once that happens, you don't have any turbo boost.

ting belt

THank you- As it turns out the "boost hose" did pop. The dealership re-attached and appears to be running well. THanks again.