1990 240 Runs very rich

I have had the car off the road for a year and have now licensed it again......it is running very rich, with black smoke coming from exhaust. Runs very rough until it warms up after a cold start. If anyone has any idea why this would happen after sitting for a year, I'd certainly like to hear them.....I am not familiar with all of the sensors on this car and need help. Thanks in advance for any help you can give me....it still runs reasonably well, but has very poor gas mileage and leaves the cars following me in a smoke screen when starting from a traffic light. All help appreciated.....