MSD woes

[factman]

i tried to time my type4 2.5L the other day that has MSD ignition on it and i cant get the timing light to work, and no its not broken, i tried it on another car and it worked. the light will blip speratically every few seconds and thats it. doesn't matter what wire i hook it up too, even the center coil wire. i know the timing is off but with such a big motor i dont want to screw up and give it too much advance while guessing. has anyone had any problems with MSD like this before or do i need a special kind of timing light? the one i used was a digital one much like a Snap On light. thanks guys.