Hi Brad,
I had the very similar symptoms with a 97 GTX I picked up last year.
No beep was caused by a dead buzzer, tapped the little metal diaphragm inside the beeper with a small screw driver and it would work for a couple seconds then dead again, just ended up replacing it. Works great now.
You will need to get a spark plug tester to doubly confirm you are NOT getting spark, even when everything is working, the spark is difficult to see using a spark plug if you are in full daylight. Be sure the plugs are grounded well to the engine, just leaving them lying on top of the cylinder head might provide a solid ground.
My issue was that the magneto bolts had sheered off and the magneto had stuck to the stator, so the mag would not turn with the crankshaft, so no pulse to pickup coil, no spark. In my case though, the white wire that runs to the back electrical box was not showing any voltage when cranking. In your case you are seeing voltage on the white wire, which drives the primary coil in the ignition coil.
You stated that you checked the coil, primary and secondary for resistance. If you left the boots on the plug wires you will need to add about 5K for each boot, or unscrew/remove them first to check the secondary. Wiggle the secondary wires while you measure the resistance and see if the meter jumps around. While you have the boots off, snip a few mm of wire from the ends of the boots before you screw them back on.
If you want to check the stator and pickup coil, I found it easiest to trace the wires back to the MPEM box in the front, open the box carefully, disconnect them from the MPEM and measure the resistance there. Again, since you are getting a pulse on the white wire, that would seem to indicate that the pickup coil is sending a signal to the MPEM, which in turn drives the white wire to the coil.
I recall reading that the secondary of the coil could check out OK but in use may not function correctly, it is a pretty inexpensive part (coil, wires, boots) to replace, you could try that, and always have a spare if that is not the issue.
As mentioned in prior posts, there are a few other things to check if it is not starting, you may be getting spark but no fuel, and or insufficient compression in the cylinders. You can take the plugs out, put 50ml of fuel/oil in each cylinder, replace the plugs and crank it to see if may be a fuel delivery issue.
Good luck!
Good Luck!
