Hmmm, that's strange that you have that kind of voltage when the key is turned to the "on" position. Next step I would try is to have someone try to start the car while you shoot some starting fluid into the intake (carefully). Once it kicks keep shooting a little more in there to see if you can keep it running for a little while longer. If it keeps going longer than the second or so it has been running that will tell you your problem is fuel related.

I would also have someone crank the engine while you hold that voltmeter onto the positive post of the coil to see if juice is constantly there while cranking and once you release the key into the "on" position.

Don