First here is the link to the Greddy site that has the manual and other documentation.
http://www.greddy.com/tech-support/e-manage/
240sx ECU e-manage Pinout
e-manage Main harness pinout
Main Harness Wiring in Parallel: Red to 12V power from ECU, Black to ECU ground, Brown to RPM signal,
Main Harness Wiring in Series: White to Airflow Input 1, Green to Airflow Output
Main Harness Injector Wiring all in Parallel: Black/Red Injector Ground, Purple/Red Injector Channel 4, Yellow/Red Injector Channel 3, Orange/Red Injector Channel 2, Blue/Red Injector Channel 1
Ignition Harness Wire in series: Ign Out is going to ECU and Ign In goes to engine bay
Instead of buying the ignition harness just disassemble the main harness and harvest two wires that are not going to be used. If you can't do this find a harness connector that you don't need and break it up or disassemble and take two from it. You can plug these directly into the e-Manage. Take some pliers and crush the metal a little flatter then it is so that it will hold onto the pin better and electrical tape or heat shrink it.
If you don't have the support tool cable and know how to solder go here:
http://wilbo666.pbworks.com/w/page/4648 ... 9SEPCBFile
This link is less intense support tool cable making write up costs a couple dollars more and some wait time to get parts from china.
http://www.migee.com/2010/05/06/diy-gre ... m-scratch/