I want to upgrade my factory external ignition coil to an MSD ignition coil but I just noticed that there is a harness plugged into it. What does it do? Could I just unplug it, take out the factory ignition coil and put the MSD ignitioncoil in? If I did that, would the check engine light come on?

 

you need to connect the appropriate wires, im not sure which two wires the msd coil wants, im gonna guess igition signal and i dont know the other one.....

look in the manual

 

The coil simply has a positive and negative (charge and ground). Honda has packaged this into a neat connector which mates to their coil, but MSD's universal coils are.... universal. You will need to replace your factory connector with some eye or spade terminals which will work with the MSD coil.

Check out http://www.msdignition.com for their reccomendations for what works well with OEM inductive ignitions. The Blaster SS seems to be popular and isn't too expensive. If you have the extra money I would go for a 6A box so you have a complete ignition. With the 6A box you will be able to use a nicer CD coil as well.... The temptations a cost just keep going up, don't they.