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Nissan Xterra - Bad smell on startup

I just bought a used 2006 Xterra. I didn’t notice this during the test drive, but when I first start it up, I’m blasted with a strong bad smell. What could be causing this?

We need more info. Where is the smell coming from?? Is it the vents?? Does it go away?? What does it smell like?? Info!!!

+1 to gsragtop’s comment.

The way that the OP has his/her question phrased is the automotive equivalent of phoning a doctor and telling him that you have a pain in an unspecified part of your body, and wanting to know what is wrong with you. Without more specific info, nobody can provide any advice that will be really helpful.

If it is a “rotten egg” smell, and temporary only, it is likely the catalytic converter, and I would not worry about that. Many cars do that.

If it is soome other smell plese tell us what is smells like.

I sincerely apologize for being unintentionally vague.

The smell is from the exhaust. its only noticeable if the windows are down. It does appear to go away once the car has been driven/idling for some time. But intially, it is there…it kinda smells like some chemical…amonia maybe? I’ve googled this and it does appear to have happened to quite a few owners of Xterras, but no one seems to know why it does.

If the smell is from the exhaust, the first thing I would do is to change brands of gasoline.
Some brands of gas have a higher sulfur content than others, and this can lead to unpleasant exhaust odors.

Also–if the smell goes away once the engine warms up, it is possible that you are just smelling the effects of the “richer” gas/air mixture that is present during the initial warm-up phase of the engine.

If the smell is coming from the exhaust at startup, you are probably smelling hydrogen sulfide, not ammonia. This is normal in many cars, implying that the fuel/air mixture is initially too rich. If the smell clears after warmup there is no problem. It is harmless. You can either live with it or replace an expensive catalytic converter with no guarantee of improvement.

Thanks VDCdriver & SteveF. If I remember my chemistry correctly, I believe it does indeed smell like hydrogen sulfide. I’ll leave the catalytic converter as is. Good to know its not something I have to fix :slight_smile: