engine overload

Joe Sau · Aug 22, 2010

Bula Guys, having a problem with hitachi ex100-3. When i try to lift or move, it overloads the engine and sometimes stops the engine. Had the controls serviced but same problem occurs. Any ideas??

AKKAMAAN · Aug 22, 2010

Joe Sau said:
Bula Guys, having a problem with hitachi ex100-3. When i try to lift or move, it overloads the engine and sometimes stops the engine. Had the controls serviced but same problem occurs. Any ideas??

Its hard to say in detail without a schematic symbolic drawing, but your excavator have a load sensing, LS, closed center system with a variable piston pump....seems like pump is receiving max load signal when you activate the control..... there should be a QC for a pressure gauge on the signal line....also check the pump supply pressure (pump out let line), which should be somewhere between 300-600psi when control are in neutral....and 600psi-5000 psi, depending on load, when control is activated...
You will need a 0-6000psi gauge...(some pressure reliefs are set over 5000psi)

Question: does it overload even if you just try to "feather" the control?

Dead Horse · Aug 22, 2010

Also, check ALL of the QC's to make sure they are fully engaged.

I have seen situations where a hose was left prressurized whan an implement was removed, serviced and the QC would not mate up properly without relieving the pressure in the hose.

It has happened to me once with the loader on my big tractor.

I had to take a large drift punch and a hammer and "pop" the nipple in the fitting. When doing this I strongly recommend gloves and safety glasses.

Duff · Aug 23, 2010

Replace the fuel filters.

I have had similar situations on other machines.
Simply put the swash plate in the pump cannot flatten out quickly enough to stop the machine from stalling.
The machine is stalling as it does not have the horsepower, to lift the load due to blocked fuel filters.
If it doesnt stall you will find the hydrualics are very slow

Duff