Fuel injectors not working, Low voltage.

[Bleach67]

I found the problem with my 1990 Nissan 240SX KE24E SOHC. All four injectors are getting only 8-9 volts only when cranking, there is a pulse from the ECU however it's very weak. the Multimeter shows 8-9V across the plug, but shows a full 12v when you use the battery NEG.

The battery is new fully tested and works flawlessly. Always charged at night.

What the heck? I have probed everywhere I can, in the injector harness and relays. 12v.

Any ideas, I am stumped.