Hello,

I have a Plymouth Valiant from 1965 with 225 slantsix.

To my problem, I have changed wire harness in the car from "Keep It Clean Wiring", becouse the old one was very bad.
Now when i start the car, it cranks and try to start, have had it sound like it started, but when i release the key, the engine stops.

I dont know much about the car, but iknow it has electronic ignition as i was told by previous owner.
I have changed ballast resistor without any change.
I have spark and fuel and changed vacuum hoses.

Now im out of ideas, do you got anything i could check or try out?

http://www.mymopar.com/downloads/Dual_Ballast_5pin.pdf Go there look at wire to ignition switch has both start and run circuit. Sounds like you have lost power on run circuit. The rest of that wiring not for your car.

http://www.mymopar.com/index.php?pid=18 more info

http://www.mymopar.com/index.php?pid=109 66 dart manual might be close but may not be exact match

About half way down this page wiring out lined in yellow look at ignition ballast. J2-16DBL is from run side of ignition switch,check for power there with key in run postition.https://www.slantsix.org/forum/viewtopi ... 28&t=64914