Switch my be sloppy, but it doesn't sound like it's the problem if you have cut wires. Sounds like you're getting power to the ignition if you're able to stop it with the key - just can't turnover the engine with it. You need to trace back where the purple wire was cut. I'm not familiar with the '66 so others can chime in, but you should be able to trace it back to the bulkhead connector, and then under the dash where I believe is should connect directly to your key switch.

 

purple wire ought be for the starter solenoid, not ignition. The yellow wire ( @ solenoid) gives the coil a full 12v while cranking.

 

My 66 has had the ignition wire cut at some point in the engine compartment. The wire I believe is the purple wire. When I turn the key I'm not getting power to it. I can jumper the wire to start the engine by going to my battery source. The ignition works to shut the car off.

The purple wire should only get power in the cranking position correct? I have a floor shifter but I don't think there is a functioning neutral safety to interfere. There will be in the future.

The ignition key is very sloppy and requires lots of jiggling to get it to the on and the start position.

Could this be a bad ignition switch?

Is anyone with a diagram willing to share?

This is my first attempt at getting it on the road after about ten years so I'm a bit rusty.

Thanks

Your key and tumbler are certainly worn out, a new set is in order or you can get a locksmith to repair the key and tumbler section, good luck!

 

The purple wire is for sending power (during key in cranking position) to the neutral safety switch to energize the starter solenoid.
The power wire feeding the ignition switch is red.

1966 Chevy Chevelle - Malibu & El Camino Color Wiring Diagram

Complete basic car included (engine bay, interior and exterior lights, under dash harness, starter and ignition circuits, instrumentation, etc) Original factory wire colors including tracers when applicable Large size, clear text, easy to read Laminated for ease of use

classiccarwiring.com