I installed this kit on my car it has worked, but keeping the car stopped and idling this no longer works which may be the cause
I’m sure you’ll understand that we cannot answer this question.
It can be anything: mechanical cause, assembly problem, defective component, unit incompatible with the existing ignition system.
Start by checking the kit, make sure it works fine. Remove it from the car and test it with a lightbulb instead of ignition coil.