High pressure fuel pump always running at 700-720 psi even under load

[Losgalos]

Has anyone experienced this my car has been running lean with slight stutters and misfires when warm.
Data log shows rail pressure always at 700-720 even under load.
Goes from 720 psi to 1300 when misfires.
When not misfiring it maintains 700 /720 psi even under load.
Fuel pressure never drops below 700,
Since the HPFP never drops below idle target(.even under load)
I'm wondering if something else is bad and not the HPFP

By my understanding fuel pressure should spike up to 2500 psi under load ,but this is not happening.
Getting some misfire codes too.

[PerformanceEngSolutions]

Originally Posted by Losgalos

Has anyone experienced this my car has been running lean with slight stutters and misfires when warm.
Data log shows rail pressure always at 700-720 even under load.
Goes from 720 psi to 1300 when misfires.
When not misfiring it maintains 700 /720 psi even under load.
Fuel pressure never drops below 700,
Since the HPFP never drops below idle target(.even under load)
I'm wondering if something else is bad and not the HPFP

By my understanding fuel pressure should spike up to 2500 psi under load ,but this is not happening.
Getting some misfire codes too.

Seems like your HPFP is done. You’re right fuel pressure should be above 2,000 psi under low rpm load and above 1,500 psi minimum at high rpm load.

Check out swellengear hpfp rebuild thread that was sometime in September or October. You can measure the depth of the thermal compensation diaphragm with a pair of calipers. If the diaphragm is deeper than 16 to 18mm then the hydraulic oil filling has leaked out preventing the pump from creating pressure