kern303

i have a 91 civic dx with a jdm GSR swap, converted to obd1, mpfi. running on a chipped p28. i just swapped in a new trans and now it turns over but won't start.
things i've checked that are working right:
ECU
-all fuses circuit tested (under dash and under hood)
-checked all grounds (even voltage tested from the battery ground to thermostat -ground with key ON)
-all plugs are connected
-when i just the wires for ECU Codes the CEL stays steady on. (but ECU is good)
-I have spark
-i have fuel pressure
-the Main Relay clicks on and off
-the motor starts with starter fluid

What could be the issue?
thank you for the help!