96 civic w/98 engine wont start

i have a 96 civic hb. the engine crapped out so i replaced it with a 96 lx engine. both non vtec. compression and airfuel is good spark is inconsistent. i replaced the distributor and computer still nothing. it cranks on then immediately cut off. all ground wires are connected and i dont know what else to check

is there a difference in the timing of these engines

are the ECU's for both engines the same? i dont know much about a civic. are there any difference between the engine you had and the one you put in? you say the spark in inconsistant, do you mean no spark at all or is it off time or what? If you havent seen the new engine run before or unless you got it from a good friend or family member you should make sure the timing belt is good and on its marks up to the tooth. also try swapping your last engines distributor onto it if you still have it.

what exactly happend to your last engine?