hello, im having trouble diagnosing 2 John deere 450d lc excavator issues. both with the izuzu engines. the problem i am having is fault code "1239-1 low fuel pressure/ stage one" both of these excavators have the identical code and symptoms. they have white smoke really bad sounds like they're running on a few cylinders with little to no throttle response. im in michigan and its cold right now about 25F. one has the code and symptoms constantly while the other machine has the code come and go. im stumped on this problem anyone that has encountered this before or know of this issue with any insight would be tremendously appreciated as im needing to use these machines. Thank you!!
I don't know the code definition but I know someone that will! LOL Have you replaced the fuel filters and checked for fuel line restrictions?
1239.01 code is a high pressure fuel pressure mismatch code (Actual vs Desired) and your filters are the most likely short term fix. The 450DLC fuel filtering system is a bit sensitive. I attached a bulletin on the subject.
thanks so much! ill pass this information along to my mechanics and get new filters on them and go from there. ill post how it turns out and if it cures it.
On top of what's stated above, you may want to check for any water in the fuel system (fuel tank, filters). In the temps you are seeing there any water will freeze, especially overnight, and cause a restriction on the suction side of the system. I'm sure there are areas in that system that are not easily accessible by the heat of the engine at operating temp which may not allow the ice to melt away. Replacing the fuel filters will take care of any water in them, but will do nothing for water between there and the suction side of the fuel tank. I have seen this several times this year as I do every year. JMO
Excellent advice. Make sure you check that also CS.
Your symptoms sound exactly the issue I had with my Hitachi, I can't remember the code but it ended being the suction control valve. I replaced the filters and drained the fuel tank to no avail, after I installed the new valve everything was back to normal.
Hello Having same issue. Where is this valve located or part number. Ron