1999 763 electrical problem..please help

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vcci

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Feb 6, 2007
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I just bought a 99 763 that has some sort of electrical problem. After starting and leaving it running for a couple of minutes the thing just turns off. The hydrolics are also not operating for some unknown electrical problem. I had the hydrolic system checked out and was told that it was fine and an electrical problem is to blame for the non-operation. I'm thinking the two problems are somehow related and was hoping someone can point me in the right direction in order to solve these problems. Thanks in advance for you help.
 

skidsteer.ca

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Is it a G series (triangle head lights) or a F series retangular head lights.
Can you drive it around? just the loader will not move or is the park brake/pin engaged also?
Are there any warning lights lit on the dash, If its a F it has a box beside the seat on th rh side with 5 green lights, all should be lit when the seat bar is down. If it has the green “push to operate” button on the dash these 5 lights will not come on until the bar is down AND the button is pushed.
How many hours?
Ken
 

Tazza

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Is it a G series (triangle head lights) or a F series retangular head lights.
Can you drive it around? just the loader will not move or is the park brake/pin engaged also?
Are there any warning lights lit on the dash, If its a F it has a box beside the seat on th rh side with 5 green lights, all should be lit when the seat bar is down. If it has the green “push to operate” button on the dash these 5 lights will not come on until the bar is down AND the button is pushed.
How many hours?
Ken
I too think it could be a seat or seat bar sensor. When these detect the seat bar is not down or there is no one in the seat it will not allow the hydraulics to operate. It should also lock the park brake too (if its still connected).
It makes sense why it shuts down, i suspect its just a safety device to prevent any chance of it running away with the operator out of the seat for a long time.
 

vcci

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I too think it could be a seat or seat bar sensor. When these detect the seat bar is not down or there is no one in the seat it will not allow the hydraulics to operate. It should also lock the park brake too (if its still connected).
It makes sense why it shuts down, i suspect its just a safety device to prevent any chance of it running away with the operator out of the seat for a long time.
I think now that you guys mention this seat sensor it makes sense. I can drive it backward and forward but only if I accelerate more on the throttle. Also it does seem to have a hard time to disengage the brake system. When I first bought it I had a hard time getting it to drive because of the brakes. I had to turn the switch on and off a few times before it disengaged it. The unit had about 1800 hours and I am not sure as to the model of it. I bought it sunday and sent it staight to the mechanic so I don't really remember if it's the G or F model. Another thing is that the lights on the right side of the dash blink showing no oil pressure but the pressure was checked and is okay. I will have the mechanic check that sensor you guys are talking about and hopefully thats all it is. Thanks for you help so far. If you can think of anything else I should have the mechanic look at please let me know.
 

vcci

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I think now that you guys mention this seat sensor it makes sense. I can drive it backward and forward but only if I accelerate more on the throttle. Also it does seem to have a hard time to disengage the brake system. When I first bought it I had a hard time getting it to drive because of the brakes. I had to turn the switch on and off a few times before it disengaged it. The unit had about 1800 hours and I am not sure as to the model of it. I bought it sunday and sent it staight to the mechanic so I don't really remember if it's the G or F model. Another thing is that the lights on the right side of the dash blink showing no oil pressure but the pressure was checked and is okay. I will have the mechanic check that sensor you guys are talking about and hopefully thats all it is. Thanks for you help so far. If you can think of anything else I should have the mechanic look at please let me know.
okay it's definately s G series as the lights are triangle lights. Where can I find the sensor? I thought it was an F series but I was wrong. I'm sure if I can find the sensor and replace it will take care of the problem. Thanks again.
 

Tazza

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okay it's definately s G series as the lights are triangle lights. Where can I find the sensor? I thought it was an F series but I was wrong. I'm sure if I can find the sensor and replace it will take care of the problem. Thanks again.
I'm not too sure where they are on your machine, but one should be where the seat bar pivots, you should see 3 wires going into a small round gizmo, this is the sensor. There should be one for the seat too, i hae seen them under the ROPS where the seat bolts down, it too should have 3 wires going into it.
Its quite common for the problem to be the seat sensor because the seats can rot away under here causing all sorts of problems with the sensor.
 

vcci

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I'm not too sure where they are on your machine, but one should be where the seat bar pivots, you should see 3 wires going into a small round gizmo, this is the sensor. There should be one for the seat too, i hae seen them under the ROPS where the seat bolts down, it too should have 3 wires going into it.
Its quite common for the problem to be the seat sensor because the seats can rot away under here causing all sorts of problems with the sensor.
I replaced the safety sensor for the bar where it pivots and that didnt take care of the problem. I also cheked all the fuses and sensors and they all seem fine. I checked the codes in the unit and was given codes 4-14, 5-14 and 5-15. They all refer to some sort of either engine pressure or hydrolic pressure which the machanic checked and all were fine. I am thinking maybe it's the whole electrical unit on the top tight of the dash, maybe that part is not good. The mechanic will replace with another 763 and maybe that will do it. I'm sure the problem is not a major one buy one of those annoying things that are hard to figure out. Is there anything else I should look for? Thanks for everything.
 

Tazza

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I replaced the safety sensor for the bar where it pivots and that didnt take care of the problem. I also cheked all the fuses and sensors and they all seem fine. I checked the codes in the unit and was given codes 4-14, 5-14 and 5-15. They all refer to some sort of either engine pressure or hydrolic pressure which the machanic checked and all were fine. I am thinking maybe it's the whole electrical unit on the top tight of the dash, maybe that part is not good. The mechanic will replace with another 763 and maybe that will do it. I'm sure the problem is not a major one buy one of those annoying things that are hard to figure out. Is there anything else I should look for? Thanks for everything.
If its giving an error code for hydraulic or engine oil pressure it may be as simple as a pressure sender. I'd start by checking that they are both operational and open up when the machine is started. They should only close when there is a fault or the machine isn't running.
 

skidsteer.ca

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If its giving an error code for hydraulic or engine oil pressure it may be as simple as a pressure sender. I'd start by checking that they are both operational and open up when the machine is started. They should only close when there is a fault or the machine isn't running.
Being this is a G it has no seat sensor, and the brakes are a park pin. They are either on or off. There is no making them slip.
You should here a loud click after you pull down the seat bar, you push a Green button and then you will here the click (park pin disengageing) this green button also puts power to a valve that unlocks the lift and bucket tilt of the loader.
As far as shutdowns go, the park pin and lock valve have nothing to do with this.
From what I understand the only things that shuts the machine down is low oil pressure, high water temp, low charge pump pressure, and possibly rpm to high.
The fuel is held in the on position by a soliniod on the injection pump, if a loose connection, bad relay interupts this power the engine shuts off.
Does it always shut down after the same amount of run time? If oil pressure shuts it off, it can be restarted and run for something like 30 seconds at a time, for emergengy reasons.
If the shutdown is completely eradic, I'd be betting on a loose wire, if its always the same, then think sensor. If the Bobcat tech plugs his laptop into the machine it stores every sensor out of range reading for the life of the machine. If it a faulty sensor it should show the same fault over and over.
Ken
Ken
 

vcci

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Being this is a G it has no seat sensor, and the brakes are a park pin. They are either on or off. There is no making them slip.
You should here a loud click after you pull down the seat bar, you push a Green button and then you will here the click (park pin disengageing) this green button also puts power to a valve that unlocks the lift and bucket tilt of the loader.
As far as shutdowns go, the park pin and lock valve have nothing to do with this.
From what I understand the only things that shuts the machine down is low oil pressure, high water temp, low charge pump pressure, and possibly rpm to high.
The fuel is held in the on position by a soliniod on the injection pump, if a loose connection, bad relay interupts this power the engine shuts off.
Does it always shut down after the same amount of run time? If oil pressure shuts it off, it can be restarted and run for something like 30 seconds at a time, for emergengy reasons.
If the shutdown is completely eradic, I'd be betting on a loose wire, if its always the same, then think sensor. If the Bobcat tech plugs his laptop into the machine it stores every sensor out of range reading for the life of the machine. If it a faulty sensor it should show the same fault over and over.
Ken
Ken
I think the reason for it shutting down is the oil pressure sending unit is bad. As I said before the mechanic checked the pil pressure and said it's fine which leads me to believe that the sending unit is not sending the right information. It always stays running for pretty much the same amount of time. I will replace that tomorrow and hope it works. Can you tell me where I can find the pressure sensors? You say there are two and I only heard of the oil sensor for the motor which I will change tomorrow but where is the other sensor? Is it for the hydrolic system? Thanks a lot for everything.
 

skidsteer.ca

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I think the reason for it shutting down is the oil pressure sending unit is bad. As I said before the mechanic checked the pil pressure and said it's fine which leads me to believe that the sending unit is not sending the right information. It always stays running for pretty much the same amount of time. I will replace that tomorrow and hope it works. Can you tell me where I can find the pressure sensors? You say there are two and I only heard of the oil sensor for the motor which I will change tomorrow but where is the other sensor? Is it for the hydrolic system? Thanks a lot for everything.
One for the engine oil is just above the starter, center of the engine on the tailgate side.
The charge pressure ones are on the lines on the hydraulic oil filter, top Rh corner of tailgate area
Ken
 

Fishfiles

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I am kinda reading between the lines on your problem , and one thing I'd say you are doing wrong is you keep referring to "the mechanic checked it out and it's ok ", if it's still not fixed I would take anything for granted ----- the thing that gets me is you say you have to rev up the engine to get it to move and it shuts down on the same amount of running time , sounds like the pressure is low at and idle , it may be as simple as a loose drive belt , if the belt breaks or is so loose that it doesn't turn the pump properly , the unit will shut down after about 30 seconds to a minute from a no or low hydraulic oil pressure reading , the sensor that sends that signal is the one on the right side of the hyd filter head , there is a little fitting in between the sensor and the fitting off the side of the head it is called a snubber , it was that porious rock material in it like on the old style fuel filters on carbs of chevy trucks , it will sometimes get some trash in it and block the oil from getting to the sensor , some 7 series units when you change that hydraulic oil pressure sensor they will give you one that is a little different and you have to get a wiring pig tail to make the connection to the new sensor ,-----there is a silver connector under the cab right close to where it hinges that has a screw ring on it , have seen corrosion in the plug terminals cause the same problem you are having with the hydraulic pressure sensor shut down ------- I'd also bet you may be fighting more than one problem at the same time ---- good luck ---- fishfiles
 

vcci

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I am kinda reading between the lines on your problem , and one thing I'd say you are doing wrong is you keep referring to "the mechanic checked it out and it's ok ", if it's still not fixed I would take anything for granted ----- the thing that gets me is you say you have to rev up the engine to get it to move and it shuts down on the same amount of running time , sounds like the pressure is low at and idle , it may be as simple as a loose drive belt , if the belt breaks or is so loose that it doesn't turn the pump properly , the unit will shut down after about 30 seconds to a minute from a no or low hydraulic oil pressure reading , the sensor that sends that signal is the one on the right side of the hyd filter head , there is a little fitting in between the sensor and the fitting off the side of the head it is called a snubber , it was that porious rock material in it like on the old style fuel filters on carbs of chevy trucks , it will sometimes get some trash in it and block the oil from getting to the sensor , some 7 series units when you change that hydraulic oil pressure sensor they will give you one that is a little different and you have to get a wiring pig tail to make the connection to the new sensor ,-----there is a silver connector under the cab right close to where it hinges that has a screw ring on it , have seen corrosion in the plug terminals cause the same problem you are having with the hydraulic pressure sensor shut down ------- I'd also bet you may be fighting more than one problem at the same time ---- good luck ---- fishfiles
Okay finally I had a Bobcat dealer look at it and was told that the computer is bad. Does this make sense? If so where can I find the computer? The dealer wants $550. Is that reasonable or should it cost less? Thanks
 

cchardwick

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Okay finally I had a Bobcat dealer look at it and was told that the computer is bad. Does this make sense? If so where can I find the computer? The dealer wants $550. Is that reasonable or should it cost less? Thanks
OH MAN I hate computers, and sensors, and electronics. That's why I have an old skid steer from 1974, real ez to work on and lots of elbow room too! I would say that price sounds about right for a new computer. If you have enough down time, maybe you can check around and look for a used one. Try a tractor salvage place, it would be at least half of that I'm sure.
 

skidboy

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OH MAN I hate computers, and sensors, and electronics. That's why I have an old skid steer from 1974, real ez to work on and lots of elbow room too! I would say that price sounds about right for a new computer. If you have enough down time, maybe you can check around and look for a used one. Try a tractor salvage place, it would be at least half of that I'm sure.
Have a 1974 bobcat,but a computer and modem to be on this forum !!!!!! funny
 

Fishfiles

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Okay finally I had a Bobcat dealer look at it and was told that the computer is bad. Does this make sense? If so where can I find the computer? The dealer wants $550. Is that reasonable or should it cost less? Thanks
Some early machines I have stuck the controller from another machine and it will work , some will not and you will have to have it reprogrammed by the dealer as the software to do it is not available to the customer , if it does plug in and work the s/n and hours will be from the machine you took it out of will then be on the machine you put it on , the newer machines don't seem to swop too well , you stand a better chance of a swop working if the machine you took it out of and are putting it into are both plain jane early models , no high flow , no hand controlls , etc , as some functions have to be turned on from the lap top by the dealer , even though on the same model number machine some controllers are 2 plug set ups and some are 4 plug set ups depending on s/n breaks , which makes a replacement find even harder ----- I think you will have to bite the bullet and buy from the dealer as finding one used that will work will be like finding a 1/2 of a needle in a hay stack , you can order the controller preprogrammed for your machine and you just have to stick it in , it is located behind the left panel on side of your left foot sitting in the machine , be sure to disconnect the batterry before making the swop , the new one will probally not line up with the two mounting holes and the tire will have to be removed and one hole will have to be redrilled , $550 isn't too bad , I just changed the controller on a 334 this pass Monday and with the programming fee of $30 and tax it came to $1200, fishfiles
 
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