Hi, I just bought a 2005 Cat 311CU with roughly 8000hrs. It starts and runs great when cold, for an hour or two or three. But then out of no where it'll start bogging down under load, and eventually choke itself out and stall. Then for the rest of the day it'll make it 2-4 scoops under bogging/low power before stalling out again. It'll idle a good while if not put under load. There's no smoke out the exhaust when it bogs and I'm almost certain it's a fueling problem, but maybe some computer/sensor thing I'm not aware of? It'll usually fire right back over after stalling but on rare occasion it'll crank no start until it sits for a little while and/or after I prime the system. I put a new water separator and fuel filter in it, no change. There was some water in the old fuel filter that got past the separator somehow though. Ive been draining the separator several times a day and there's usually a little water in it. I tried draining water from the fuel tank from the drain port on the bottom as I thought any water would sink, but only fuel came out. I have pulled and checked the new filter right after bogging down, but it didnt have any water in it like the old one did, HOWEVER, it wasnt full to the brim with fuel, it was probably 1/2" down -- so I might be losing prime/getting air in the system? I have continuously reprimed the system with the hand plunger, but that doesn't seem to make a big difference in keeping it from stalling right back out. Should I start by flushing the whole tank and lines because of the water, or follow the loss of prime theory? Could that be a bad injection pump for it to fail only when warmed up? Could I try adding an in-line electric lift pump?
You have a mechanical engine with a conventional fuel injection pump. However, the engine management is electronic. A Governor actuator is used to control the fuel rail. Several sensor parameters are monitored to properly control engine speed. Also, the Governor actuator control cables stretch over time. I assume it's possible to calibrate the Governor actuator using CAT ET. Please provide the serial number; it's required)
You're correct that the cables stretch but ET cannot be used to calibrate them. It's done using the Monitor Panel and cab controls. Need a S/N to confirm.
CAT0311CVCKE01621
Maybe check and/or adjust the cables as a first step, then try calibrating the governor actuator. There are three steps in the attachment and you may have to do them in a different order to which they appear.
Got it, will do, thanks. You believe this might be related to it stalling only when warm rather than a fueling issue?
Not necessarily, but you have to start somewhere. The next step might be to look at the hydraulic system performance.