773 G - Wont move

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SBLGFD

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Nov 20, 2012
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Hello to all and thanks in advance! I have been reading and learning – but my first po st. First of all the machine is 200 miles away and trying to gain information from family members via the phone. Here is what I know so far. Machine is a 773 G with about 2000 hours on it, it has the digital display with the keyless start etc . Symptoms started several months ago with the machine not wanting to move (Release the brake) unless the RPMS were up , if the RPMs were dropped the brake would engage. This would continue until the machine warmed up then it would operate normally. This continued for a while but sounds like it slowly degraded to the point the machine would not move at all. Dealer said it was the RPM sensor on the flywheel; this was replaced with the machine not moving at all now. Other known items Loader portion works fine Three of four green lights are on with the one not lit – they think brake release light is not on. Digital tac was all over the place, now no reading at all – blank I asked if they could hear the brake solenoid activating – answer was unknown – may have answers tonight Also asked if the machine would move at all – 1-2 inches – again answer unknown Wondering your thoughts Thanks – Chris
 

OldMachinist

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Sounds like the RPM sensor is still the problem. Test the resistance on the sensor it should be 3000-3500 ohms. If that checks out okay then it may need to be adjusted properly. The gap between the end of the sensor and the flywheel needs to be .050". To adjust engine needs to be off, loosen the jam nut, turn the sensor in until it contacts the flywheel, turn the jam nut down until it contacts the flywheel housing, turn the sensor and jam nut together until you can get a .050" feeler gage between the nut and housing. Tighten the jam nut without turning the sensor and reconnect the wiring.
 
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SBLGFD

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Sounds like the RPM sensor is still the problem. Test the resistance on the sensor it should be 3000-3500 ohms. If that checks out okay then it may need to be adjusted properly. The gap between the end of the sensor and the flywheel needs to be .050". To adjust engine needs to be off, loosen the jam nut, turn the sensor in until it contacts the flywheel, turn the jam nut down until it contacts the flywheel housing, turn the sensor and jam nut together until you can get a .050" feeler gage between the nut and housing. Tighten the jam nut without turning the sensor and reconnect the wiring.
Thanks for the reply, I questioned them on how they installed it. They were aware of the .050 separation. They said that the new RPM sensor comes with a auto setting feature?? They were instructed to run the sensor down on the fly wheel and start the engine. Apparently there is some sort of sacrificial end cap /spacer that comes off when the machine is started? Sounds to me like they should reset that gap. Chris
 

OldMachinist

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Thanks for the reply, I questioned them on how they installed it. They were aware of the .050 separation. They said that the new RPM sensor comes with a auto setting feature?? They were instructed to run the sensor down on the fly wheel and start the engine. Apparently there is some sort of sacrificial end cap /spacer that comes off when the machine is started? Sounds to me like they should reset that gap. Chris
Yes, the new sensor comes with a plastic cap that's supposed to come off when you start the engine the first time if its in contact with the flywheel. It can't hurt to check it.
 
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SBLGFD

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Nov 20, 2012
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Yes, the new sensor comes with a plastic cap that's supposed to come off when you start the engine the first time if its in contact with the flywheel. It can't hurt to check it.
11/20/12 Update So I called and got the following additional information Serial # 517611753 Kubota V2203 He started the machine - still no tach reading and only three green lights - but he was able to move it about 2 feet before it locked up and now back to the same issue - won't move. He was not able to hear what I call the clunk of the release of the brake, but it must have released at least for a time. I confirmed with him that while moving the fourth green light stayed off and the Tach had no reading. Thanks Chris
 
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SBLGFD

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11/20/12 Update So I called and got the following additional information Serial # 517611753 Kubota V2203 He started the machine - still no tach reading and only three green lights - but he was able to move it about 2 feet before it locked up and now back to the same issue - won't move. He was not able to hear what I call the clunk of the release of the brake, but it must have released at least for a time. I confirmed with him that while moving the fourth green light stayed off and the Tach had no reading. Thanks Chris
11/20/12 16:40 - update - pulled the RPM sensor - plastic cap was split but still on it - Oh joy we have found the problem - or not- reinstalled reset to 0.050 and no change in condition. Chris
 

Bobcatdan

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11/20/12 16:40 - update - pulled the RPM sensor - plastic cap was split but still on it - Oh joy we have found the problem - or not- reinstalled reset to 0.050 and no change in condition. Chris
You have a broken wire in the harness that is making contact sometimes. To move the machine, flip tha cab, right behind the steer councel is the brake solenoid. Remove it and pull out the the wedge. Put the solenoid back on. This will at least let you move the machine somewhere nice to work.
 
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SBLGFD

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You have a broken wire in the harness that is making contact sometimes. To move the machine, flip tha cab, right behind the steer councel is the brake solenoid. Remove it and pull out the the wedge. Put the solenoid back on. This will at least let you move the machine somewhere nice to work.
OK will start down that road tomarrow, any known common failure points?
 

Fishfiles

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OK will start down that road tomarrow, any known common failure points?
I agree with Bobcatdan that it most probally a wiring issue , would think it would give a rpm sensor code but they don't always give a code when something is wrong , seen times where you need to check for the code as soon as it happens and before turning off the igniton as the code will disappear ------------follow the wires from the plug of the rpm sensor to where in goes into the wiring harness loom ,the wires going to the starter come out in the same spot , the wiresare a little tight and bend hard right there and get damaged , pull the wire with your finger and thumb and sometimes you can see the plastic covering stretch ----another couple of spots is if you have a head liner in your machine is the screws which hold the plastic panel where the a/c controlls would go , the wiring harness gets damaged by the screws , also check the big plug connector under the cab for corrision ---------could also be the stem coil of the brake valve
 

Bobcatdan

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I agree with Bobcatdan that it most probally a wiring issue , would think it would give a rpm sensor code but they don't always give a code when something is wrong , seen times where you need to check for the code as soon as it happens and before turning off the igniton as the code will disappear ------------follow the wires from the plug of the rpm sensor to where in goes into the wiring harness loom ,the wires going to the starter come out in the same spot , the wiresare a little tight and bend hard right there and get damaged , pull the wire with your finger and thumb and sometimes you can see the plastic covering stretch ----another couple of spots is if you have a head liner in your machine is the screws which hold the plastic panel where the a/c controlls would go , the wiring harness gets damaged by the screws , also check the big plug connector under the cab for corrision ---------could also be the stem coil of the brake valve
There are no RPM code. If there is no rpm signal, the controller will assume the engine is off. It doesn't take into account the other sensor reading. The dead give away there is rpm problems is the glow plugs will cycle when the engine is running.
 

Fishfiles

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There are no RPM code. If there is no rpm signal, the controller will assume the engine is off. It doesn't take into account the other sensor reading. The dead give away there is rpm problems is the glow plugs will cycle when the engine is running.
Yesterday I was working on a T190 , was changing a starter and was looking right at the RPM sensor and thought of this post as I know I had seen codes related to the RPM sensor before , so I under plug the sensor and it came up on the screen as engine speed - no signal , granted the code doesn't say RPM sensor but it means the same thing ------so does the wheeled 773 not do engine speed codes
 

Bobcatdan

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Yesterday I was working on a T190 , was changing a starter and was looking right at the RPM sensor and thought of this post as I know I had seen codes related to the RPM sensor before , so I under plug the sensor and it came up on the screen as engine speed - no signal , granted the code doesn't say RPM sensor but it means the same thing ------so does the wheeled 773 not do engine speed codes
Maybe depends on software version. Every machine I ever had rpm sensor problem never had any codes. I don't know everything.
 
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SBLGFD

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Maybe depends on software version. Every machine I ever had rpm sensor problem never had any codes. I don't know everything.
11-23-12 update Hope everyone had a good Thanksgiving! Spent a fair amount of time yesterday trying to find an issue, unfortunately no luck. Checked the wires as best we could, dropped the head liner out , tilted the cab etc all with no luck. Pulled the solenoid and did the hose clamp trick loaded it on the trailer and off to Madison Bobcat we go. The good news is they cant find it either so we did not miss anything, the bad news is they are stumped as well. They are calling tec support on Monday to see if they can get some direction. When we had it running the glow plugs would continue to count down, and the display continued to show push the start button to start all while running. all for now Chris
 

Bobcatdan

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11-23-12 update Hope everyone had a good Thanksgiving! Spent a fair amount of time yesterday trying to find an issue, unfortunately no luck. Checked the wires as best we could, dropped the head liner out , tilted the cab etc all with no luck. Pulled the solenoid and did the hose clamp trick loaded it on the trailer and off to Madison Bobcat we go. The good news is they cant find it either so we did not miss anything, the bad news is they are stumped as well. They are calling tec support on Monday to see if they can get some direction. When we had it running the glow plugs would continue to count down, and the display continued to show push the start button to start all while running. all for now Chris
It is not seeing rpm, if the sensor is good, wiring is good, put a controller in it.
 
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SBLGFD

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Nov 20, 2012
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It is not seeing rpm, if the sensor is good, wiring is good, put a controller in it.
11/28/12 update Bobcat called last night they believe its the computer that needs to be replaced. They had a used one on the shelf a installed it as a trial run and all seemed to work, so they are installing a new style and we should have the machine back in the near future. Thanks for all the help Chris
 

Tazza

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11/28/12 update Bobcat called last night they believe its the computer that needs to be replaced. They had a used one on the shelf a installed it as a trial run and all seemed to work, so they are installing a new style and we should have the machine back in the near future. Thanks for all the help Chris
Sure hope it fixes the problem. Do keep us posted.
 

7LBSSMALLIE

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Feb 2, 2012
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Sure hope it fixes the problem. Do keep us posted.
i agree that should solve , couple of points, laptop can monitor rpm voltage signal(dead give away) also lets look at cause, was it old style snap together lid controoler. if yes it was due. also bad batts will fail a controller faster than any thining. you been jumpining it?
 

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