With the parts numbers being different, I would start with the correct knock sensor.
Did you use a shielded wire, and ground one end? This is how the rewire for the '86-'92 Supra's is done, using a 50 Ohm 18 to 22AWG multi-strand wire.
I used a normal coax, audio cable. Its probably closer to 12 gauge wire. Doesnt the wire from the ecm run straight from the ecm to the sensor? Is the sensor not grounding it? I'm confused about that.
