75 chrysler only starts when cold

[chad201]

The model # is 756h4l. This motor starts and runs great on the first crank early in the morning when it is cool but in the heat of the day it won't spark at all. I have 12 volts at the blue wire on the distributor but no fire from any of the plugs. Any suggestions or info on this motor would be great.

 

[MickLovin]

It may possibly be your optical sensor which replace the old points, I was lucky in the fact I had a spare dizzy to try out for this problem.