Hydraulics work good with engine speed on “I”. Bump up engine speed to “L” and hydraulics are slow. Short time after cycling hydraulics they started to work on “L” then bump up to “E” or “P” and hydraulics are slow. Engine speed control motor is erratic. Controller could be on P but engine RPM is at idle. Cable to the governor was replaced recently. Pump output matches voltage being supplied to the solenoids on top of the pump. No flash codes on the controllers. Pump output seems to be matching command from the controller. Could the issues with the engine speed control cause the controller to request low hydraulic pump output?
Fitst I would Verify actual engine RPM vs. controller display using tachometer. then check for stored codes in engine controller (even if not flashing). then check throttle position sensor calibration. based on post, your engine speed control is causing your hydraulic issues. Here's the connection: 1. The engine controller communicates with hydraulic controller via CAN bus or discrete signals 2. Hydraulic pump displacement is adjusted based on engine RPM feedback and load demand 3. If engine controller sends incorrect RPM data (thinks engine is at idle when it's actually high RPM), the hydraulic controller limits pump output to protect against over-speed or overload Your symptoms confirm this: - hydraulics work at low RPM setting = system functioning, just being limited - Bump RPM up = controller thinks there's a mismatch, restricts pump - Eventually works after cycling = controller "relearns" actual conditions temporarily - Erratic engine speed motor behavior = faulty engine speed controller or sensor feedback Root cause options: - Engine speed controller failure: Sending bad signals to hydraulic controller - RPM sensor/feedback issue: Engine controller doesn't know actual RPM, sends wrong data downstream - CAN bus communication error: Controllers not talking properly - Governor linkage/cable issue: New cable installation may have calibration problem - controller commanded position doesn't match actual throttle Fix the engine speed control system first - your hydraulics are fine but being limited by bad engine data.
Was all this a problem before the speed control cable was replaced? I'm not sure on your machine but I was thinking those had to be calibrated after replacement.
You’re right V, engine learning procedure screenshot below
Thanks for the info! I’ll try the calibration procedure. Is there an adjustment procedure for the cable that should be performed before calibration as well?
With the key off , if the injection pump lever is against the low idle stop the cable from the throttle stepping motor is adjusted correctly. The long story below is from the manual. .
Thankfully Dave beat me to this question. I knew there had to be an adjustment parameter but I didn't have the specs.
I completed the calibration and it fixed the erratic engine speed control issue but it didn’t change the slow hydraulic issue. If I make small engine speed adjustments with the up arrow it will consistently cut off hydraulic flow at around the same 1400 RPM range. Works normal from around 900-1400 RPM. I unplugged the engine speed sensor and it seemed to go into a hydraulic limp mode at about 1/2 hydraulic speed but worked the same at any engine RPM. Do you have test specs and a wiring diagram for the engine speed sensor?
Key off. Disconnect harness from engine speed sensor. Connect an ohmmeter to N sensor terminals. Measure resistance. Does ohmmeter read 810 ± 240 ohms? Engine running, Measure AC voltage at N sensor terminals. Increase engine speed. Does AC voltage increase as engine speed increases ?
Speed sensor wire harness check. . EC harness terminals identified a bit better in screenshot below.
Just returned to this machine since the snow melted. Sensor resistance is 943 ohms. Its output was 292 mV at idle and increases with engine speed. Readings at the ECM connector & the sensor match. Does not seem to be connected to the speed sensor or the pump displacement sensor. Is there a service connector on these machines to connect with a laptop?
Resistance of the speed sensor was in spec. Voltage out of it went up & down with engine speed. Tapped on the top of it a few times with a hammer and everything started working normal again. Going to replace the sensor.