1976 series 2 xj6l refuses to run
 

Hello, i am caught with a predicament, my series 2 XJ6 refuses to run, when i turn the key to ignition it starts and continues to run as long as i hold the key in ignition, the moment i let go of the key from ignition it dies. I guessing i could be the ignition coil, i'm mechanically inclined but i don't want to start poking into somewhere not related to the issue. Any form of help to point me in the right direction would be sincerely appreciated. thanks.

As I recall, there is a ballast resistor by the coil that is by-passed when the engine is turned over, and when the switch reverts to "run" it is re-connected. Maybe this is the problem. The ballast resistor is there to allow a 6-volt coil to be used on the 12 volt system. Why ? Because on engine start the starter motor draws so much current the voltage to the coil drops a lot, so a 12 volt coil is trying to make a good spark with 7 or 8 volts, but 6 volt coil just works fine.

Thank you, to bypass this for a test, i'm thinking to run a wire from the + 12V battery directly to the + on the coil. I'll look into that this weekend, hopefully that's all it is.

There are aftermarket coils designed to run at 12V all the time. I'd get one of those if I was in your situation. The Accell 8140 is designed to run a 12v but its a bit smaller so you will need some rubber sheet to mount it in the stock bracket. A piece of weather stripping works fine too. While at it you can replace the horrible blade connectors with some proper ring terminals.

I had this problem some years ago. The ballast resistor had a burnt out wire. I got it running by twisting the ends together. Then I replaced it with a new ballast resistor!