Can a High Pressure HPDI Pump just be bad

[Br3ttc@hotmail.com]

I have had the HP Pump on my HPDI rebuilt twice by Flagship in the last 20 hours of operating and after 10 hours of solid performance the surging and engine problems re-emerged. Changed the Fuel/Water Filter with a new 10 micron filter and let the motor rest overnight. Ran great for an hour.

Put the gauge on the VST and ran hard for 20 minutes and low pressure was pretty constant (48-50) PSI.

Do I just need to try a different or new High Pressure Pump. I know Flagship is good but are some pumps un-rebuildable?

Thanks,

Brett

[Sequoiha]

I think so, I have had to replace a coulple over the years,, but i just replace the pumps, not the body of the pump

[rodbolt17]

its a mechanical pump, however regulators can go bad and filters can clog.
have you monitored HP pump pressures?

[seahorse5]

Have you replaced that super expensive filter between the VST and the high pressure pump lately?