This isn't an excavator-specific set of questions, but really more specific to the Mitsubishi engine - and this is a gray-market machine for which I've got a parts book (in Japanese) and no other documentation. The 4D32 seems to be a relatively common engine in Asia, but not stateside.
I've got some kind of fuel-circuit problem that's resulted in poor power and missing. I had the tank out due to a pinhole, & this was a long-duration repair. In the meantime, I ran it occasionally to reposition & do some light work, and during that time, fueled from a simple jury-rigged 5-gal bucket setup. Far as I can recall, it ran OK prior to the leak, though I wasn't using it much. I'm certain it took up some air during tank-swapping, but it never really seems to have bled.
Now the real tank is back in, I've bled it to death, and it's still missing like crazy and stumbles/dies very easily. I don't think it's a simple filter-clog, since fuel flows out the top of the filter-housing if I pull the 1/8" pipe plug, and all the injectors spit at me while I crack their nuts open at idle - though I should mention the impact on the idle of cracking each of them is far from consistent or uniform across the four.
Here's one of my big unknowns about the fuel circuit: there are three tank hoses. One's clearly the return. Another is obviously the feed to the normal-service mechanical fuel pump, which has a typical hand-primer pump built in. But the third hose...a short length off the bottom of the tank feeds an electric clicker pump, also mounted on the bottom of the tank, and that pump pushes fuel directly to a port that's on the 'front' (small end) of the IP. That IP port is physically quite near to the return port, but just 'around the corner,' so to speak.
There was no filter in this line, which bothers me a lot, since it's definitely set up to push fuel /towards/ the IP. The electric pump is, I think, only intended for some kind of bleeding assistance when it's run dry - I say this because there's a spring-return, momentary rocker switch that powers it from the cab, so it's not intended to be left on. (Who'd want to pump gritty, sludgy, near-bottom-of-tank fuel to the IP after running dry?)
Or did I get that wrong?
Anyway, I'd never had much luck with the electric pump helping or hurting, but it and the IP hose connections are concerning me as unknowns, now that I've got this lumpy, irregular running.
I'm thinking I might order & replace injectors and see what that does for me - but is there anything else to check first?
Thanks - Dave
I've got some kind of fuel-circuit problem that's resulted in poor power and missing. I had the tank out due to a pinhole, & this was a long-duration repair. In the meantime, I ran it occasionally to reposition & do some light work, and during that time, fueled from a simple jury-rigged 5-gal bucket setup. Far as I can recall, it ran OK prior to the leak, though I wasn't using it much. I'm certain it took up some air during tank-swapping, but it never really seems to have bled.
Now the real tank is back in, I've bled it to death, and it's still missing like crazy and stumbles/dies very easily. I don't think it's a simple filter-clog, since fuel flows out the top of the filter-housing if I pull the 1/8" pipe plug, and all the injectors spit at me while I crack their nuts open at idle - though I should mention the impact on the idle of cracking each of them is far from consistent or uniform across the four.
Here's one of my big unknowns about the fuel circuit: there are three tank hoses. One's clearly the return. Another is obviously the feed to the normal-service mechanical fuel pump, which has a typical hand-primer pump built in. But the third hose...a short length off the bottom of the tank feeds an electric clicker pump, also mounted on the bottom of the tank, and that pump pushes fuel directly to a port that's on the 'front' (small end) of the IP. That IP port is physically quite near to the return port, but just 'around the corner,' so to speak.
There was no filter in this line, which bothers me a lot, since it's definitely set up to push fuel /towards/ the IP. The electric pump is, I think, only intended for some kind of bleeding assistance when it's run dry - I say this because there's a spring-return, momentary rocker switch that powers it from the cab, so it's not intended to be left on. (Who'd want to pump gritty, sludgy, near-bottom-of-tank fuel to the IP after running dry?)
Or did I get that wrong?
Anyway, I'd never had much luck with the electric pump helping or hurting, but it and the IP hose connections are concerning me as unknowns, now that I've got this lumpy, irregular running.
I'm thinking I might order & replace injectors and see what that does for me - but is there anything else to check first?
Thanks - Dave