If your machine won't idle down it could be a couple of things. Is the green light coming on? The reason I ask is if your oil pressure switch is faulty you green light won't come on and your machine won't idle down and you will notice a drain on your battery. If this is the case you can best check this by putting a jumper wire across the screws of the pressure switch, if your machine idles down, change the switch.
If you can take the white wire from the board and scratch it to the case of the machine (to ground out) and it idles down THEN and only then is your board faulty.