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
Probable causes of an engine running rich are as follows: 1. Excessive fuel pressure can be cause by restricted fuel return line
2. Defective Oxygen Sensors.
3. Leaking injectors and fuel pressure regulator.
4. Coolant temperature sensor out of calibration.
5. Restricted air intake system.