help with my 240sx situation, please

[bransonfink]

Car: 93 240sx
I replaced the head and both cams ( bought off a member from nico forum)
all mating marks are lined up both on lower and upper timing chains. Everything is set at TDC
I am not sure of mating marks on crankshaft and lower timing chain since I didnt need to go that far to replace the head and cams. I did forget to hold back the tensioner when I first removed the Idler sprocket, but kept the chain from falling. Tied the chain off and placed a wood spacer against the tensioner and side wall(so it wouldnt expand) and continue working. I put head and cams in place, put in correct shims for both cams, check clearance, all OK, all mating marks were lined up , distributor is set on #1 firing position.
Fuel pump reactivated and injectors reconnected.
Car turns over good but wont fire, checked spark from plugs, all working
Ran compression test without sparkplugs in any cylinders, but only got a reading of 90 PSI on all cylinders. If valves weren't seating properly would I get the same reading on all 4 cylinders??????? I would think some readings might be low and others high. I think that either an intake or exhaust valve is slightly open on the upward compression stroke before it fires allowing some air to escape and giving me low reading. FSM says min. 150 to max. 180 at 300rpms
Anyone have any suggestions???? Any information would be helpful
Thanks

[nismoracingsx]

240sx-180sx-silvia-forum.html

Better off trying here in the "Technical" section ^_^ GL