Car won't start

[BLUE CUDA]

I have a 1970 Plymouth Cuda 340 4-Speed. My Problems began with the car while it was running it completely died out. I left it for 2 hours, went back, and it started up once again. It kept doing this for a period of time. I replaced the Electronic Control Module, and it still wouldn't start. I replaced the Electrical Ignition Switch, and like the Module, it wouldn't start. I replaced the starter, still no start. I disconnected the new Ignition Switch and connected the old Ignition Switch. I turned the old Ignition Switch to the start position and let back a little bit, and the car started and ran. When I let go placing it in the run position, the car stopped running. I am totally confused! Can anyone please shed some light on my dilemma? HELLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLPPPPPPPPPPPPPPPPPPPPPPPPPPPPP.

[dodj]

What kind of ignition system? Stock? Aftermarket? Single or dual ballast resistor?

[BLUE CUDA]

My points system was converted to an Electronic Ignition system with the orange box two prong Ballast resister.

[Bullitt-]

If the starter always cranks the start side of the switch & wiring seems to be good so the issue must be on the run side.
If you leave the switch in the run position & test for voltage at the ballast resistor you would know if the switch & wiring are good. If no or low voltage there check at every connection along the way till it's lost.
If appropriate voltage is present at the ballast resistor then follow it to the coil. 

[HP_Cuda]

Ok I might be losing it but doesn't the ECU setup have a 4 prong ballast resistor?

[Bullitt-]

Ok I might be losing it but doesn't the ECU setup have a 4 prong ballast resistor?

1st generation did, later models and retrofit kits only use a 2-prong

[HP_Cuda]

Wow good to know...

Check the ballast resistor, probably the easiest to fix off the bat.

[BLUE CUDA]

Replaced Ballast resister still no go. How would I test for Voltage at the ballast? With test light?

[Bullitt-]

Replaced Ballast resister still no go. How would I test for Voltage at the ballast? With test light?

Best thing to use is a multimeter, then you can see what the actual voltage is, a test light only shows that there is some not how much...a poor connection could let for example 9V through which would not start the car. 

[BLUE CUDA]

Put voltmeter on VDC then put one prong on each side of Ballast, no reading on Voltmeter.

[Bullitt-]

You ground the black (-) lead to the body of the car.. red (+) goes to the wire on the ballast.

[BLUE CUDA]

Thanks, I am new to voltmeters use. I will try this tomorrow, must sleep now to work tomorrow. Thanks again. Hopefully with you great bunch of Mopar friends I can solve this.

[Sleepychallenger]

what about the starter relay?

[Racer57]

I had a tach short out and prevent the engine from starting. Might check that out.

[BLUE CUDA]

Their is no voltage at the ballast resister. So do I check on the wiring back to the ignition switch? How do I check to see if the starter relay is good?