2012 Isx 2350 475 with codes 4726 and 0559

[Rawze]

(02-17-2022 )ahrenbenjudah Wrote:  It only cranks so I can’t do a rail leakdown test unfortunately. If I key on, the rail is fluctuating between -50 and -10 psi. That’s with a new pressure sensor installed and a new relief valve installed.

with the key on and the electric fuel pump running, does it have plenty of fuel flow and pressure at the compu-check test port when its pressed in?