Texasmark1
Well-known Member
1988 3910, all OEM, 900 hrs when purchased last year, have 75 hrs on it since working it pretty good. Starts in a flash, runs and holds after turned off (gauge on engine) 50# oil pressure, runs up to 2200 rpm about as fast as you can pull the throttle, gooses fast with the foot pedal (advance mechanism in pump working just fine).....not that I do this as a habit but for troubleshooting purposes here....new fuel filters, input lines burped, and I use clean, fresh fuel with PS (gray bottle) additives.
At idle and up to 1200 rpm runs real smooth. Going above that rpm I get enough of a miss to make the exhaust loud and you can tell that something changed. Cracking the injectors, the center has a good pattern at idle and up around 1800....2 data points. #1 and 3 not so much....obviously not as much fuel being delivered, or what is delivered not enough pressure to squirt like #2.
Best I can tell nothing on the engine has had a wrench on it. Timing mark is aligned at 0 and looking at the OEM paint, never been moved since built.
Seems to me something is not providing consistent fuel supplies to all cylinders evenly, especially at the higher flow rates and what could it be but the pump.......butttt the pump supplies enough fuel to the injectors to easily achieve the service manual listed red line rpms.
As usual, thanks in advance.
Mark
At idle and up to 1200 rpm runs real smooth. Going above that rpm I get enough of a miss to make the exhaust loud and you can tell that something changed. Cracking the injectors, the center has a good pattern at idle and up around 1800....2 data points. #1 and 3 not so much....obviously not as much fuel being delivered, or what is delivered not enough pressure to squirt like #2.
Best I can tell nothing on the engine has had a wrench on it. Timing mark is aligned at 0 and looking at the OEM paint, never been moved since built.
Seems to me something is not providing consistent fuel supplies to all cylinders evenly, especially at the higher flow rates and what could it be but the pump.......butttt the pump supplies enough fuel to the injectors to easily achieve the service manual listed red line rpms.
As usual, thanks in advance.
Mark