don't have a manual... need help with ECU codes

im not exactly sure how to read the ECU codes off of this old thing...

i had two different kinds flash at me... one was all of the lights burning 8-4-2-1

and the other one was only 2 lights burning
8-4

is there a list somewhere of ECU codes that i can reference back to
and can someone tell me how to read these codes off? PROPERLY?

Both codes indicate a faulty ECU.