Originally Posted by Diseasel300

I ask about the pressure issue because it can be hard to tell. The 1/2-1PSI of positive pressure that can build in the tank can be alarming, but it's normal. Negative pressure is not normal.

The lift pump is the sole fuel circulator in the fuel supply system. It draws fuel from the tank, fills the fuel filter, fills the fuel rack, and maintains pressure in the system against the overflow valve on the back of the IP. Fuel delivery to the injectors is drawn from the fuel rack and pumped by the high pressure elements in the IP. The only electronic gizmos involved in fuel delivery are the overboost switch (which cuts off boost pressure to the ALDA if boost goes too high) and the EDS solenoid which maintains idle speed. The car can and will run with both of those systems bypassed.