exhaust smokes when starting engine

2000 Camry - V6

friend swapped engine out with a ebay engine, lasted couple months

sat for almost 2 years after engine swap, it didn't survive

had a shop fix the alternator

now the cars exhaust smokes every time no matter time of day or every time it starts through out the day.

Once in a great while after putting oil, it'll stop a little, but smokes again.

Engine light stays on

Please help