firing problem

hello-everyone i have a 1991 buick regal 3800 gs i just replaced the harmonic balancer-the problem is the car isnt firing-the car being sitting up for 4 years-what seems to be the problem??

i have 1991 regal gs-i just replaced the harmonic balancer 3-2007 becaused the rubber was bad!! the car being sitting up for 4 years-the problem is the car is not firing--what do i need to look for!!!! i used a h/b puller to take it off-i did not mess with the crank sensor!!!

Was it firing before the harmonic balancer replacement?

Was it firing before the harmonic balancer replacement?
the car did start it been 4 years since its been running or tried to started

Do you think the gas in the tank is ok? Are there any trouble-codes? If the vehicle cranks good, but won't start, have a helper crank the vehicle, while you check for spark at the plugs and injector pulse. If you have spark and injector pulse, check fuel pressure.