1990 Jeep Cherokee LTD no start/no spark

Hey guys,

I've got a very frustrating problem here. Customer brought in a 1990
Jeep cherokee limited, 4whldrv, automatic. We replaced the engine with
one from a 1996. All the appropriate electronics were switched from
the old engine to the new including, distributor, cap, rotor, coil,
CPS, flywheel, intake and exhaust, all injectors (already on old
intake). The problem is we now have a no start/no spark condition.
This swamp is common at our shop, (newer 4.0L into older jeep) and
always goes off without a hitch. This is the first time I've run into
this. We've replaced the CPS, coil and ignition module check out O.K.,
Distributor checks out. We even put all the suspect parts into another
jeep and they worked fine. The computer has also been replaced but to
no avail. Any input would be appreciated. Thanks.
Jesse