87 Nissan D21 Ignition problem

[Patr2020]

Hey guys,
so I just bought this 87 D21 4 banger and the damn thing just doesn't want to run... so I checked for the basics, Air (compression was 175-160 on each cylinder), fuel hot wired the fuel pump it works, also replaced the relay for the fuel pump, and spark.

The spark is being the issue here I have 12V from the coil which drops to 10V when I'm cranking, this is normal as far as I can tell. but the charge doesn't seem to go to the spark plugs, not seeing anything when I crank it over with a plug attached and grounded.

I have replaced wires, plugs, rotor, cap and the coil/ module. The only thing left for me to change is the ECM, so I take the passenger seat out and try to run the diagnostics which is the switch type on this truck. I do not see the green or red light, light up at all under any circumstance key on/off with the switch in either position (diagnostic / normal).

does this mean my computer is fried? I unplugged the cables and noticed some white corrosion type substance on a few of the pins, then opened the cover of the computer and noticed a couple electronic components had this white stuff on them too.

Please let me know what you think!

cheers

[Patr2020]

Am I on the right track or totally out to lunch?