how do i tell if there is spark coming from the spark plug wire?

 

Pull the sparkplug wire, put a sparkplug in it, hold it to ground (ie the engine block) and crank over the motor.
Make sure to always have it grounded when cranking....that is very high voltage!!!

 

A couple ways. If you have a timing light you can hook the inductive pickup to each wire and watch for flashing. A more effective way is to pull each plug one at a time and ground the casing to the head (just touch it to the outside of the head with an insulated pair of pliers and gloves). Then have a buddy turn over the engine and watch for spark. Don't do this for long, just a few seconds. With practice, you can determine strength of spark as well, something that the timing light method won't tell you.