Not getting any fire

[7TCuda]

Hey guys new to this forum. I have a 70/340 Cuda with an intermittent ignition fire..Car was running great, then it starting getting hard to start.  Start sometime and then not at all. Now its not starting. I checked the spark, and on initial first rotation of engine, I get a single spark and then nothing. After trying to crank the engine for say 5-10 seconds, when I turn the ignition off to try and crank again, it seems it gets fire for a spit second, because it ignites and trys to run in opposite direction.  I changed the electronic box, coil, ballast resister and ignition switch with no success. I even shot 12 volts to the coil with a power probe and that didn't work. Checked the dizzy cap and rotor and they seem ok. Never changed the pickup in the dizzy yet, thinking they hardly ever go bad.
Wire harness is new, car was restored not by me, but was turnkey when I bought it 3 years ago. I'm thinking they wired this car with a 71 wire harness, if that even matters.  Any thoughts would be great!  Thanks 

[RUNCHARGER]

The pickup can go bad. Is it set to .008 clearance using a brass feeler gauge?

[Cudakiller70]

Also be sure of a good connection on this wire plug and wiring to plug is solid.

[Cudakiller70]

Maybe bad ballast, try jumping a bypass wire across

[7TCuda]

Thats my next move, change the pickup and see if that works..Car is in the shop, Ill go by a do that tomorrow. However I did ot check the gap, I'll do that first..
Thanks Sheldon

[Brads70]

The pickup can go bad. Is it set to .008 clearance using a brass feeler gauge?

Just learning.... why a brass feeler gauge? 

[Katfish]

A brass blade should be used to set a reluctor air gap.
If a ferrous metal is used you may magnetize the reluctor and cause it to function incorrectly.

From the web

[jordan]

When I first bought my car, it was running fine.  Then it started running poorly.  Kinda hit and miss.  I got good advice here to check the gap.  I did and it was way off.  A quick adjustment and I was on my way.  I hope this is all your problem is. 5 minutes and free is a good thing. 

[RzeroB]

Seems like a lot of these old rides are susceptible to issues with old wiring and connectors ... particularly the main bulkhead connector(s) and those within the steering column for the ignition switch. 

[RzeroB]

When I first bought my car, it was running fine.  Then it started running poorly.  Kinda hit and miss.  I got good advice here to check the gap.  I did and it was way off.  A quick adjustment and I was on my way.  I hope this is all your problem is. 5 minutes and free is a good thing.

The distributor mag pickup to reluctor gap I assume?? If it keeps going out it may be that either your distributor bushings or the shaft itself are worn and there is excessive radial play which would make setting and keeping the correct gap all but impossible.

[Chryco Psycho]

Welcome to the site from Panama 
I have seen this many times where the cars is hard starting or runs poorly because the gap is out , definatley check that first 

[chargerdon]

Check the battery!    I'm assuming you have an electronic ignition.   Even if it is putting out good amps to crank the engine, if the voltage drops below 9 volt while cranking the ECU will not give the signal to fire.   I have had this problem...   Put in a new battery and now it starts a lot better.   Yes, i also couldn't believe that a battery can put out enough amps to crank fine, while dropping voltage.

Its kinda stupid design of stock electronic ignition.   While cranking the system bypasses the ballast so that coil gets full 12.5 volt, BUT, at the same time the voltage to the ecu drops because it then runs thru the ballast...  So, if battery is weak, then it might not have enough volts (9 v) to fire the ECU.   

I have had this problem !