87 Lesabre Wont Start

I got a lesabre that has been driving me nuts here. Came home from work one night, shut off the car, the next morning, would not start. I tried it later that day and after much cranking it started, ran fine, then after shutting it off, would not start again and thats where I am now. The computer gave me no codes when I checked. Here is what I have replaced: ICM, crank sensor, MAF, O2 sensor, and swapped the ecm with a known good one. One note: I installed the crank sensor without removing the harmonic balancer and using the old bracket. The balancer was replaced about 4 years ago when the engine was overhauled. I checked and there is no spark on any of the plugs. I am out of ideas here, what else can cause this?

Did you check the gap on the crank sensor when you installed it?