Have a 73 challenger with 440 just hooked up the wirining harness to it yesterday it wil turn over but no spark from the coil. What are some of the quick checks I can do on it today such as checking the coil or distrubutor or ballast resistor or other stuff any help would be appreciated.

Take the yellow "ign" wire off of it's terminal on the starter relay on the fender to (termporarily) disable the starter. Take the coil wire out of the dist & hold it 1/4" from ground. Take any/all wires off of the coil negative primary terminal. W a jumper wire w alligator clips on each end ground this neg pri terminal (the terminal not the wire you removed from the terminal) to ground repeatedly like Morse Code as your helper holds the ign key to "start" and see if the coil secondary wire held 1/4" from ground makes a nice blue spark as you make/break the coil pri circuit. This tells you that all these: ign2(the start circuit)/ballast/coil and their attending wiring are OK and that only leaves the ECU (or its ground) and the dist pickup (and or both of these 2 items' wiring) but w it not firing since the rewiring prob the wiring is not right. I'd go to the archives & find what needs to be changed in your wiring

Went out and did some checks. I think I found a problem but am not sure. With both negative and posative wires removed from the coil and the ignition switch in the run position they are both hot with 12 volts. Dosent seem correct to me. Any ideas on this ?
thanks !
Dave

The wire from the coil negative pri terminal to the ECU should not be hot.

What could be causing it to be hot any ideas on how I can fix this ?
Thanks!
Dave

can you open my attachment? It has diagrams.

Attachment would not open. I still dont know what would cause the wire to be hot when it shouldnt be.
Thanks!
Dave

David I cannot get my (own) attachment to open either . I saved it as it had 2 excellent pics from "Healthservices" on here of the 5 pin ECU/dual ballast and the 4 pin/single ballast setups. I will send it from my computer to your email address & see if it goes thru. EDIT I just sent it & checked and it said "attachment stripped". I think it was too big to go thru (it was 4 pages) and I couldn't figure out how just to send the 1 page w the pics. but yes that wire should not be hot as it grounds the coil pri neg terminal to ground inside the ECU when the ECU is triggered by the dist pickup. Access those diagrams and find what wires need to be changed.