Or measure the primary dc resistance (may be easier) which should be adequate to privide the 4-5 amperes that you want for your transistor switch to conduct. Taking a nominal 12v and 4 amps you need at least 3 ohms of dc resistance between the power applied from the ignition switch and the coil terminal that goes to the electronic ignition module. If you don't have it, get a ballast resistor in the circuit that will get you there.
Did you get instructions for installation, like a note that says that an xyz ohm ballast resistor is required with this coil?
Some ign. modules warn you that if you over current the circuit, which you seem to be doing, you can kill the module due to overheating the switching transistor.