Nissan Repair: ac problem, compression check, sparkplugs

Question
1 smoke came true ac windows

2 after long time start the engine & put in the d gear car is not     running  

Answer
Asanga,

The engine will have to be inspected to see if there is engine damage.  When smoke comes out of the vents that leads one to think either you have a headgasket blown or an issue with compression.  I would have the compression checked first to see if the engine is in good order before spending money on things like sparkplugs and the like.  If the engine has not thrown a timing belt and the compression is good then a tuneup is in order.

The long start time would lead me to think the fuel injectors are leaking and flooding the engine, making the engine difficult to start.  Pulling the plugs, in concert with the compression check, will give an indication as to how the injectors are performing.  If the plugs are black and wet with fuel would mean the injectors are leaking.  If this were the case the injectors would need to be replaced as well as the sparkplugs.

Email me back and let me know what the findings are and we will continue the process to isolate the problems with your engine.