No spark 73 roadrunner

[adk-roadrunner]

Hey guys I'm having yet another problem with my 73 roadrunner. The car is a 318 with an msd coil and the orange mopar performance box. I replaced both of these last year when I was trying to diagnose a stalling problem which ended up being timing and carb. So when I took the car out the first Time this year I let it run for a while and after shutting it down it would not start again then about an hour later it fired up. A few days later I went for a drive and it just died while driving and I had to get towed home 30 minutes later it fired right up. Both times when it wouldn't run I checked for spark right off the coil wire that feeds the distributor and nothing only one spark when I turn the ignition off. I was told to replace the ballast resistor so today I fired It up and pulled it out and after shutting down same problem. I tried the new ballast resistor and still nothing so I put the original coil and ecm back in to see if it was either of those and it wasn't. I am totally stuck now I tested for voltage at coil in run and it's only 10.5. I'm so stuck please help lol.

 

[idrivemopar]

Double check the white connector that connects the steering column to main harness. If its not good you can lose the connection that keeps the car in run mode. I had a similar issue with mine one day and it was a loose connection there.

 

[old_skool]

only one spark when I turn the ignition off.

This points to the ecm, either it's defective, or not getting power,or being affected by heat, and changing more than one component at a time, makes it hard to diagnose, plus, using old parts to test, is useless unless you know for a fact they are good.

 

[adk-roadrunner]

I tried all parts one at a time included the original ecm then coil

 

[bm02tj]

Have you changed the pickup and reset air gap to reluctor as heat affects the pickup coil
and wire in some temporary indicator lights so you know if it is a loss of power

 

[adk-roadrunner]

Well I took a break from the car for a while but did some work on it today and got her going. I decided I should update this thread even though I posted a different one so it would have closer. I ended up testing the pickup coil in the distributor with my ohm meter on the 2000 ohm setting and got nothing. I then put the ignition in the on position and used a jumper wire to jump the 2 sides of the 2 wire connector on the car side and every time I did that I got spark on my tester off the coil. I then figured it must be the pickup coil so I stole the one from my mopar performance distributor for my 440 I'm building and bam she fired right up after getting it back together. Thank you everyone for all your help and sorry I didn't update sooner but I had to take a break from the car.