Does my 91 olds have a timing belt or chain? AND how do you fix It? specifics Please

There are two different procedures based on Vin # for the timing CHAIN. Reply with your email address and I can send you the pdf with instructions if that is in fact the cause of your problem. You need to discover if you are missing air (compression), fuel or spark. Have you tested for spark? Just because you hear the pump, doesn't mean you're building pressure. If you have spark and when you crank it you hear "normal" compression, add propane or carb cleaner to the intake to see if you're missing fuel.

Failing balancer has most likely damaged the crank sensor wiring or the sensor that's mounted directly behind it... Common issue with the 3.8L.. They do make a noise when failing that's for sure! .. The result of this would be > no spark! .. Which is easily tested.