Hydraulic oil leak

funwithfuel · May 10, 2019

Bigger fuse, look for smoke. Lol just kidding. Start at the protected components. Unplug them, replace the fuse and see if it fails. If so move further down to harness connections. Look around for where cabling goes through bulkheads and around corners. Look for pinches, chafes and burns. For some reason guys love to put grease guns and shovels in the battery box or the pump room.look for damage there as well. If you have serviceable diodes in the fuse panel, check those as well for shorts

Mikeyp756 · May 10, 2019

funwithfuel said:
Bigger fuse, look for smoke. Lol just kidding. Start at the protected components. Unplug them, replace the fuse and see if it fails. If so move further down to harness connections. Look around for where cabling goes through bulkheads and around corners. Look for pinches, chafes and burns. For some reason guys love to put grease guns and shovels in the battery box or the pump room.look for damage there as well. If you have serviceable diodes in the fuse panel, check those as well for shorts

Lol you literally mad me stop and reread that first sentence. Sounds like trying to find a needle in a hay stack. I’ll try thanks.

excavator · May 11, 2019

Disconnect your EC motor and see what happens, then start working your way towards the EC. Never disconnect any component with the key on, while I have occasionally done this by accident and haven't had a problem, you can blow your EC or PVC by doing it.

Mikeyp756 · May 12, 2019

mg2361 said:
First follow FWF and Delmers suggestions and make sure your engine is operating properly. Maybe post a video of the machine stalling? I think the -2 machines have the electronic hydraulic pump on it (maybe post a picture of the pump top). If it stalls fairly quickly and has the pump I think it has then check your pump and valve controller fuses (the ones highlighted in the attachment). I would check all fuses just in case. If fuses are all good then one of the solenoids on top of the hydraulic pump could be bad (there is a lot of other variables with the electronic controlled pump that could cause stalling).

Thanks for your reply mg2361. Is that definitely the fuse box for my hitachi ex120-2? Because I don’t have the lid for it. And can’t find it in the manual. It is a gray market machine. Here’s what’s happening. As soon as I turn the key on the fuse blows. Third one from bottom on left. According to your diagram it’s for the ec motor fuse. So I disconnected the ec motor and the fuse still blew. After checking some wires I decided to plug ec back in and unplug the pvc. Now Fuse does not blow. Is it definitely the pvc?

mg2361 · May 12, 2019

My information is from a 490E Deere which is similar to 120-2 Hitachi so I am not 100% sure it is the same. If you are blowing the F3 EC motor fuse with the EC motor disconnected then the problem could be the wiring to the EC motor or the engine controller itself (see attached). It could be the wiring from the relay to the ECU as well (the load side, not the control side). Which controller did you unplug, the top one (Engine controller) or the bottom one (the Pump and Valve controller)?

Mikeyp756 · May 12, 2019

mg2361 said:
My information is from a 490E Deere which is similar to 120-2 Hitachi so I am not 100% sure it is the same. If you are blowing the F3 EC motor fuse with the EC motor disconnected then the problem could be the wiring to the EC motor or the engine controller itself (see attached). It could be the wiring from the relay to the ECU as well (the load side, not the control side). Which controller did you unplug, the top one (Engine controller) or the bottom one (the Pump and Valve controller)?

I unplugged the bottom one the pvc and with top one plugged in the fuse doesn’t blow.

excavator · May 13, 2019

mg2361 said:
My information is from a 490E Deere which is similar to 120-2 Hitachi so I am not 100% sure it is the same. If you are blowing the F3 EC motor fuse with the EC motor disconnected then the problem could be the wiring to the EC motor or the engine controller itself (see attached). It could be the wiring from the relay to the ECU as well (the load side, not the control side). Which controller did you unplug, the top one (Engine controller) or the bottom one (the Pump and Valve controller)?

A 490E is the same as a 120-2&3. The main difference is Deere uses a Deere engine and Hitachi the Isuzu but the EC motor wiring ect. should be the same. Is this a 1 amp fuse that is blowing?

mg2361 · May 13, 2019

excavator said:
Is this a 1 amp fuse that is blowing?

Like Excavator, I need to know what amperage was the fuse that is blowing (if in fact the correct amperage is in there to begin with)?

Mikeyp756 · May 13, 2019

It calls for a 1 amp fuse but has a 5 amp. Most of the fuses are 5 amp

Nige · May 13, 2019

Mikeyp756 said:
It calls for a 1 amp fuse but has a 5 amp. Most of the fuses are 5 amp

In the words of Charlie Harper - There it is......!!
In what world does a 5A fuse replace a 1A because the 1A keeps blowing..?

Mikeyp756 · May 13, 2019

Nige said:
In the words of Charlie Harper - There it is......!!
In what world does a 5A fuse replace a 1A because the 1A keeps blowing..?

Lol. I get your point Nige and those fuses were in there from the day I bought it. I’ll change them all but I believe the 1 amp fuse will blow also don’t you?

Nige · May 13, 2019

It will definitely blow. Your problem appears to be more major than was at first thought if it needs a fuse of 5x the original designed rating to stop it blowing under normal circumstances. The fact that someone put 5A fuses in everything doesn't make it right.

Mikeyp756 · May 13, 2019

So it appears my short is somewhere between the ec and pvc

Mikeyp756 · May 13, 2019

Is there a way to test the pvc? Red Led flashes on both ec and pvc

excavator · May 13, 2019

Yes there is a way to test them but it's a bit complicated. If your red lights are flashing there's a pretty good chance that they are not the problem. The F3 fuse is the EC motor relay circuit. Down below the EC & PVC and forward towards the seat is a row of relays. I will have to check which one is for the EC motor. Do you have a service manual? If not, it's looking like you will probably need to get one.

Mikeyp756 · May 13, 2019

Thanks excavator, I do have a service manual. I found the relay on the right side for ec motor. Had corroded wires. Repaired them but didn’t help.

Mikeyp756 · May 13, 2019

Today I swapped Ec relay and engine stop relay. Ec fuse did not blow. Didn’t have time to run it yet. Question: if relay was blowing the Ec fuse would that make the engine bog down under load? I know I can just run it to find out but it might be a couple days before I can get back to it. And should I take the horn relay or other instead of using the possibly burnt relay for the engine stop relay.

joelx777 · Aug 21, 2022

Mikeyp756 said:
Today I swapped Ec relay and engine stop relay. Ec fuse did not blow. Didn’t have time to run it yet. Question: if relay was blowing the Ec fuse would that make the engine bog down under load? I know I can just run it to find out but it might be a couple days before I can get back to it. And should I take the horn relay or other instead of using the possibly burnt relay for the engine stop relay.

What happened?

Hydraulic oil leak

funwithfuel

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