I just purched a deere 120c excavator with 4200 hr most of the time it has a miss at high rpm but not all the time. Has anyone experienced such a problem?
I guess it still has a mechanical Stanadyne injector pump? If so, check the return line to see if it's stopped up. Crack it and see if it idles smoothly. It will get stopped up from the rubber coupler inside that disintegrates with about that many hours on it. If so, then it's time for a injector pump rebuild. If it's a newer style pump, then it could be in the computer. I see it has the 4045H engine. Also check your fuel filters, water separators, transfer pump banjo screens, and supply hose to pump. Is it smoking? Could possibly be a bad injector, can you crack them one at a time to see if one of them has no effect on idle? It's better to do this when the oil is cold so compression is better.
Thanks for the info It idles smooth and does not smoke, however, just recently it acted as if running out of fuel and as a quick fix I installed an electric fuel pump and seem to have helped but not fixed. I will check the return line and let you know.
You need to check your fuel supply line at the transfer pump, it'll have a screen inside of a banjo fitting somewhere. It's usually close to the pump, but on our Hitachi EX300 it's at the tank. I bet it's clogged up. It'll look like this with a screen inside of a hollow bolt: http://images.search.yahoo.com/imag...sigi=124kuh99b&sigb=1271mji33&fr=ytff1-ydwnld
Deere engines dont have the screens like isuzus do. Are you getting any codes on the engine diagnostic display? The DE 10 pumps really dont like ulsd fuel, so run some howes or stanadyne lubricity iimprover in your fuel and that should help , as lond as your pump isnt on its way out
Wasn't aware of that. What about water in the fuel stopping up separator?
Wasn't aware of that. What about water in the fuel stopping up separator? I didn't see where he was burning ulsd.
Wasn't aware of that. What about water in the fuel stopping up separator? I didn't see where he was burning ulsd. How about another post?, I guess i'm getting my count up.
thanks for all the help; I have installed fresh filters, no water in the fuel, there is visual evident that fuel is returning to the tank so that line is open. I did give it a good dose of the recommended fuel treatment and it seem to help a great deal. The miss seem to subside under a load but very prominent with no load and high RPM
did you ever solve this issue?