S4000-01 low power

S4000-01 low power

Had a complaint of low power and slow RPM responce from a Unit Ring MT4400 with a 16V4000-01 engine.No DDDL fault codes.Snapshot showed that the VSG govenor wasturning on and off during acceleration to full RPM causinga delay from idle RPM tomax RPM of approx 35 seconds..Cause: faulty HP fuel pressure sensor.It is beleived that the faulty fuel pressure sensor was sending faulty fuel pressure information to DDEC faster than the DDDL could capture (min is dataread everyone second).Because DDDL thought requested fuel prssure was acheived it turned OFF the VSG govenor.See attached data: DT005 Engine during loadbox.csvshows shows the active govenor at #0 (active govenor none) when it should be #2 (active govenor VSG)DT005 HP fuel pressure swap shows the active govenor staying at #2 (active govenor VSG)