Intermittent hydraulic power loss - JD 450CLC

We're chasing an annoying problem on my 450CLC. It tends to work fine in the morning with full power to all hydraulic functions. However, it will sometimes without warning lose hydraulic power and all functions, including crawling, and will slow down as if somehow the hydraulic or pilot system is going into some sort of slow mode. We've cleaned the pickup strainer and changed all the filters and tighten the clamps on the oil intake pipe, etc.
The engine doesn't load up or slow down. It's just the hydraulic functions slowing down. Please note that this machine has a "2 in 1" pump and it appears that both pumps are affected, so I'm thinking it can't be a regulator problem, as it has one regulator for each pump?
We're now down to thinking it must be a pilot system malfunction or something to do with the ECM?
I would appreciate any ideas anyone may have on what this could be.

Sounds like it might be going into derate mode, do you have any codes? How are fuel and air filters? Coolant full?

overworked said:

Sounds like it might be going into derate mode, do you have any codes? How are fuel and air filters? Coolant full?

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Yes, it certainly seems like it's going into derate mode.
We don't have any diagnostic codes, but the water level sensor must be faulty, as the low water level light is lit, even though the water level is good. Could it really be that simple? That would be a hell of a relief for me.
I just got an update from the technician. He found that one of the pressure sensors on the pump is faulty and is showing ~ 6000psi at idle. We're trying to find one of those on island today to install. If not, I'll have to FedEx one in from Nortrax. I'll report back if we make any progress.
Thanks for your input.

Plz keep us up to date.

We changed the faulty pressure sensor on the pump yesterday and sure enough, that's what it was. Machine worked fine all day with no problems. So far, so good anyways...

Cant rmember if this affected the 450clc as well as the dlc...but the counterweight removal system would fool the machine into thinking you were trying to lower the counterweight (even in machines with out the system) and limit the pumps to minimum swash, to keep things safe.

The fix is to clip a wire at the PVC. if your problem persists,let me know and I'll look up the wire for you.

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cutting edge said:

Cant rmember if this affected the 450clc as well as the dlc...but the counterweight removal system would fool the machine into thinking you were trying to lower the counterweight (even in machines with out the system) and limit the pumps to minimum swash, to keep things safe.

The fix is to clip a wire at the PVC. if your problem persists,let me know and I'll look up the wire for you.

Click to expand...

Yep, we had that problem once with my 800, which has the hydraulic counterweight removal. The 450 doesn't have it though so thankfully that's one less thing to worry about. We're using the machine again today and so far it's running fine, so it must have been the pump pressure sensor. I'm keeping my fingers crossed...
Thanks for your input.

JHESL said:

Yep, we had that problem once with my 800, which has the hydraulic counterweight removal. The 450 doesn't have it though so thankfully that's one less thing to worry about.

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It will still have the wiring for the CW removal...Ive seen a number of them without CW removal do the same thing as yours.NOt sure that a bad pressure sensor on one pump will cause it to slow down as you say it does.

cutting edge said:

It will still have the wiring for the CW removal...Ive seen a number of them without CW removal do the same thing as yours.NOt sure that a bad pressure sensor on one pump will cause it to slow down as you say it does.

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Okay, thanks. You may be right on that, because the 2 in 1 pump has 2 sensors - one for each side - so I would've expected that one sensor would only affect some of the hydraulic functions. If you have a picture or a diagram of the wire on the CW removal harness that needs to be clipped, then I would greatly appreciate you sharing that. Thanks again.