4.0 i6 won't start after rebuild

I have a 2000 XJ with a 4.0 inline 6. We did a rebuild, and it cranks but won't start.
Battery, starter, alternator, all good.
getting fuel and spark.

Any ideas?? Appreciate any help!

Thanks

CPS on the bellhousing - is it plugged in/re-installed? Is it trying to start or just turning over?

I'm not positive, will have to check. But I think it is. My son did the work underneath it. It cranks, like it wants to start, but won't turn over.

OP said it's getting spark and fuel, so CPS is probably functioning. What about compression? A little oil in the cylinders might help with compression for initial start.

In many cases like this, during working through all the things and getting them working, the spark plugs get wet fouled. If it is really getting fuel and spark, and there is compression, this is most likely the problem. The other thing could be that the distributor is indexed 180 degrees off and the spark is happening on the wrong stroke.....been there and done that.

thought it was coil on plug?

timing chain go on correctly?