95 achieva cold start

I have a 95 Achieva 3.1 thats hard to start and has a rough idle when running also has a very odor from the exhust. Has the service engine light on now. It has the 12 pin connecter i tryed a paper clip to jump it no flashes from the service light. I borrowed an obd1 scanner hooked it up no reading at all. Tryed it on my 95 olds scanner worked. Any ideas. Car some times blows black smoke when first started. Larry