I'm new to the whole TBI thing, and I need some help with this one. On a TBI motor, I've benn told that you're supposed to unplug the tan/black wire to take the computer out of the mix in order to check the base timing. Well, my truck has an MSD box wired into the harness, and when I unplug the tan/black wire, the motor dies instantly. According to my mechanic buddy, it should idle a little differently, but not die. So, how do I go about bypassing the computer to check the base timing?