2001 6 speed 24v truck. Would always start up and run perfect. Went to install fuel pressure gauge and had drained fuel from fuel filter/system. I can bump starter and see 15+ psi being built. Fuel is going to inlet of Vp44 but barey any at fuel rail. Few drips on injector line 1 and 4. None on 3 after crankin and draining the battery. Im getting codes p1689 p0237, p1694 p1693. Wondering if i bumped a connectionor my vp44 is bad? need help

 

How did you install the fuel pressure gauge and where are you reading pressure? There is a large rectangular plug going to the VP but unless you disconnected it, it should still be connected because it almost snaps into place.