I found somthing written by: TravellingTec that i think is the same problem i have. But i dont understand which parts i needed and i dont know if he is on this site anymore. Is it anybody ho have gotten this email?
I work on these things quite a bit. There is a new style pump regulator spool for the hydraulic pump (Kawasaki). You didn't say how many hours are on the machine but generally what happens is the hydraulic pump will not destroke quick enough and the engine will stall out. Will it run properly in "L" or "S" mode? Another possible problem is the turbo boost sensor. If it gives an erronious high reading to the engine computer, the engine computer will derate the engine and it will stall. An easy fix for that problem is to pull the 3 wire connector off the turbo sensor (counter weight side of engine on intake manifold). This will send an electrical problem on the dash but if this is the problem the engine will carry the load. You can also use the dash to get into some diagnosing screens. Let me know how you make out. I'll check back later.
If the engine is pulling down in "L" mode, it seems unlikely that the problem is with the regulators on the hydraulic pumps. In L mode, there is no milliamps being sent to the hydraulic pumps to keep them up stroked. When the problem is with the regulators on the pump, it is generally most noticeable in H mode when the computer is sending milliamps (450?) to the hydraulic pumps to keep them upstroked. I think my next step would be to put a 20 lb. pressure gauge on the outlet side (bleed port) of the fuel filter. This is an M4 thread but a 1/8 pipe fitting will work but will leak. When you start the machine, taget pressure should be around 12 psi. If anything else was wrong with the injection pump etc. it would be putting up "electrical problem" on monitor and there would be a corresponding code shown on the diagnostic monitor. This will be the only way to tell if you are getting a good supply of fuel.
Was giving your problelm further thought. I know its pretty hard to explain over the internet but what does the unit sound like when it's bogging down? The reason I ask, there has been an ongoing problem with VP24 relay (relay that controls the electronic fuel system. It's located on frame rail counterweight side of engine below injection pump.) When this acts up, it sounds like the engine is bogging down but is different than a fuel related problem. The best way to describe it sounds like you are turning the key on and off very rapidly. When it is a fuel related problem, the engine slowly dies and may come back but this is almost like an intermittent misfire. I think the relay has to be bought from Case as it is slightly different than a normal relay and 24 volts. Let me know how you make out.
Glad that you took a fuel pressure reading. At least that should eliminate questions about supply of fuel. If you have changed the turbo boost sensor, we can assume that the engine is getting proper boost and proper supply of fuel. That only leaves the VP44 relay that could cause this problem and not put up an electrical problem on the dash. As I have stated that VP44 relay can do strange things. It has fooled man;y people into thinking that the engine was bogging but it sounds more like a steady miss under load. If you're satisfied that the problem is not in the relay, then we will have to go back to the pump regulators. Those switches and solenoids in the pump compartment, the 6 bank solenoid package has nothing to do with pump control (power lift, free swing, etc). On the hydraulic pump inself, there are 2 pressure solenoids on the tank side plus the pump proportional solenoid and the back of the pump, counter weight side. You could take that 2 wire connector apart and try the machine alt;hough as I have already stated when you run in L mode there is no current to the solenoid to upstroke the pump.After eliminating all these possibilities, we should now turn our attention to the update for the pump regulators which keep it from over stroking. I will email you the procedure and if you feel comfortable with the description, the parts are worth about $150
