New alternator

Replaced my alternator. Everything turns on and works. Took it for a test drive and it was kind of like vibrating. 3 hrs later I was warming up the car due to it being winter when I noticed white smoke and a smell. I waited till this morning to start it up again and it wasnt smoking. Anyone know what the problem might be?

Depending on the quality of the replacement, I think you got a bum one. Maybe a bent pulley or something causing the belt to smoke. Don’t know but doesn’t sound normal. Most times when you have a problem after fixing something, you go right back to the thing you fixed for the answer.

Check the alternator install first. Make sure the bolts that hold it are all tight and it’s not sitting cockeyed or something. Check the belt and all the other pulleys. You could have a bad tensioner, bad water pump, or something else on that belt causing the vibration.

Idle quality should improve with time after reconnecting the battery. The amount of steam observed from the tailpipe will vary depending on the weather when the engine is cold. Generally during cool damp weather you will see more steam.

Tailpipe steam

OIC. I was thinking smoke from the belt, not “smoke” from the tailpipe. Good catch, assuming that’s what OP meant.

If you disconnected the battery to replace the alternator, that could be the cause of the stumbling you noticed at first. As you drive the computer figures out the best parameters for a smooth idle and remember them in its computer memory. But when the battery is disconnected that memory gets erased. So it has to stumble awhile to learn all the parameters again.

White smoke out the tailpipe is normal for a cold start this time of year. If the white smoke was coming from the engine compartment, that needs to be checked by a pro mechanic. Could be an install problem or the replacement alternator is faulty.