I do not know what i'm doing but i am learning as i go.

I have a 1974 challenger and i recently put in a new wiring harness and ignition switch. When i put the Electronic ignition module on the fire wall it for the lack of a better term shorts out or grounds out. If the electronic ignition module is off the firewall (i just set in between the carb and the valve cover, the car starts and runs(i can drive it but i can tell there is some electrical issue) But if i mount it on the firewall it will not start (no spark) If the car is running and i take the electronic control module in my hand and touch it to the fire wall mounting bracket while the car is running ....the engine will die. Any suggestions would be appreciated.
I have several things to still work on on the car and have some electrical components not hooked up yet but nothing that i would think would have any effect on this situation. The engine has 2 grounds that i feel are good ground but my next step to the clean them up really good and see what happens.

 

Sounds as if the ECU box is defective.... Or.... The system is wire incorrectly...

 

I may have a bad ECU i have another one i can try. I believe it to match the diagram you posted but I will double check as it was the first time i have wired one before. I have wiring diagram for the vehicle which i tried to follow. I will double check my wire to the diagram you posted. Thanks again and I'll let you know I a couple days.

 

Sounds good... We are here to help...