cel codes. need help.

[92teg]

i have a 92 integra with a b16a. i used to have a p72 obd-I but it blew a fuel injector driver or something. they said i had an sir1 motor with sir2 wireing. so it was in safe mode and some other stuff. well i put in a jdm p30 and it runs well except the cel codes. and vtec does not enguage. it is pulling three different codes. 20, 21, and 41. 20 is electrical load detector, 21 is VTEC spool solenoid valve, and 41 is primary oxygen sensor heater. first of all what do these mean? and then secondly where should i start looking to fix these. ALSO WE PUT THE ECU IN A FRIENDS B16A2 CONVERTED TO OBD1 AND IT RAN IN HIS CAR FINE. MY CAR WITH HIS ECU DID NOT CHANGE. My mods are just intake, 2 1/4 pipe on the stock manifold with no cat and just an aftermarket muffler. any help would be very much appriciated. thanks Vern