If you don't have a tach adapter, the fuel pump, tach, and idle control will not work. The ignition coil has to be directly connected to the MSD unit and the stock negative lead must be removed. A bunch of things rely on the high-voltage kickback pulse from the coil and a tach adapter is the only solution. Well, almost the only solution... I found this out the day before a car show. MSD all wired up but no start due to no fuel. Jumpered the pump and it fired to life at about 2500 RPM. My temporary solution - a Williams pinball coil connected to the Bosch ignition module and connected to the factory coil leads. This worked because I was running the MSD in "points" mode, and it was triggered from the factory ignition amplifier. Later on, I switched to inductive pickup and disconnected the factory ignition, decreasing spark timing latency.