Hydraulics
Why do the hydraulics bog down the engine?
If engine speed drops sharply, the engine labours or stalls when hydraulics are enabled, establish when loading starts. Is it immediately on unlocking hydraulics or only with a particular function? This separates a system-wide problem from a single circuit fault.
What happens when hydraulics are unlocked?
Start the engine without moving the joysticks and move the hydraulic lock lever to the working position. Observe the engine response.
The engine loads immediately
If no function is active yet, investigate the common system: the main pump does not unload or immediately goes to high displacement, the common unloading valve fails, LS/PC/EPC or power shift/torque control is wrong, the control valve receives a continuous command or a common valve is stuck. This is not merely a single-cylinder fault.
The engine runs normally after unlocking
Then check the functions one at a time.
Check each function separately
Compare boom lift and lower, arm, bucket open and close, swing, travel and auxiliary hydraulics. Briefly reach the end of stroke and observe which function drops engine speed most. Do not hold a function against its stop for long: this heats the oil and loads the system.
One function loads the engine more than the others
Check the control valve section, local relief, spool, cylinder or hydraulic motor, pilot control, hoses and mechanical seizure.
Every function heavily loads the engine
Check pressure, main relief, pump output and displacement control, power shift, LS, pilot pressure and solenoids. At the same time, verify that the engine can produce normal power.
The engine can be the cause
A weak engine makes normal hydraulic loading seem excessive. Check fuel, Common Rail, injectors, turbocharger, air, DPF and exhaust, derate and engine speed under load.
A useful comparison
Normal hydraulic pressure with excessive engine speed drop calls for checking engine power and pump power matching. Excessive pressure or a pump that does not unload points towards hydraulics.
What you can observe
Does it load immediately on unlocking or only with one function? Which one? Only at the end stop or throughout movement? Is there black smoke, does the engine run normally without hydraulics, and are there engine or hydraulic faults?
Related problems
Further service support
Have a fault code?
Problem still there?
If these checks have not identified the cause or the fault returns, contact TSV Servis. The more initial information you provide, the sooner we can identify the next diagnostic direction.
What to send us
Send the machine model, S/N, response to the lock lever, specific function, hydraulic pressure, engine speed and pump control parameters.
Include the make and model, S/N or a nameplate photo, engine model if known, operating hours, exact code or display photo and when the fault occurs.
Also tell us what you have already checked or replaced and the results. Include a photo or short video of the symptom where useful.
+420 722 307 850 · tsvcz@seznam.cz