1999 Max UD Pulley came apart, replaced it, now won't start
 

Is the REF sensor damaged or any other ideas why a no-start condition would exist after replacing with a new UD pulley?

When you installed the new crank pulley, did you see any signs of damage to anything?

What brand underdrive pulley did you install? Has the proper timing ring?

this one And I haven't really checked the ref sensor will do it next.
http://www.ebay.com/itm/310727566242?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

That is a regular crankshaft pulley. Although it came from a different seller, it really looks like the one I installed a few weeks ago. No problems.

Could the crankshaft position sensor been damaged when the old pulley came apart?

The one on the left is the one I installed a few weeks ago.

https://cimg5.ibsrv.net/gimg/maxima....bb4536c8b6.jpg

IDK I took the old crankshaft sensor off and cleaned it and reinstalled it, still won't fire up.

I'm sure it's related, but i've had freak coincidences happen before... Have you checked spark, fuel pressure, followed the wiring harnesses? For the money, it's worth it to try another crank pulley from a different seller.

Yes I am contemplating this theory. I will try a different pulley first. Might help if I pull some codes as well..