Bobcat 751 wont start

[newty]

Hi, I have a bobcat 751 that is dead. When i turn the ignition on the warning light all light up and go off, the LCD display shows INPUT. Nothing works at all. Ive checked the fuses in the cab floor, connectors under the cab. earths in the engine bay above the battery. Any ideas or does anyone have a wiring diagram? Thanks

 

[newty]

Also its fitted with the BOSS system and was manufactured around 2001

 

[Tazza]

Also its fitted with the BOSS system and was manufactured around 2001

That sort of sounds like a controller problem..... Not what you want to hear. I'd pull the connector out of the boss box and plug it back in, just in case you have a bad connection there. It could also be your wiring harness shorting out somewhere.
Sorry i can't be of more use.

 

[newty]

That sort of sounds like a controller problem..... Not what you want to hear. I'd pull the connector out of the boss box and plug it back in, just in case you have a bad connection there. It could also be your wiring harness shorting out somewhere.
Sorry i can't be of more use.

Im thinking controller problem, the connectors seen to be fine on the boss box. Think in going to have to find a workshop manual to look into this further before price up a controller. Thanks

 

[Tazza]

Im thinking controller problem, the connectors seen to be fine on the boss box. Think in going to have to find a workshop manual to look into this further before price up a controller. Thanks

I don't think the manual will tell you much, i would call your local dealer and talk to the service department. Ask them and see what they think, they are usually happy to help out where they can.
Don't just go swapping the box out, they are not cheap and it could be something simple. I'm sure you know that anyway.

 

[Tazza]

I don't think the manual will tell you much, i would call your local dealer and talk to the service department. Ask them and see what they think, they are usually happy to help out where they can.
Don't just go swapping the box out, they are not cheap and it could be something simple. I'm sure you know that anyway.

Input could also be a dash problem, check you connectors to the display panel.

 

[TriHonu]

Also its fitted with the BOSS system and was manufactured around 2001

According to the Bobcat Historical Specs the 751G series started in 1999. Does you machine have the newer rounded cab and triangular headlights and dash is LCD black letters on grey background?
The BOSS option has a dash panel on the right side of the cab with orange icons and vertical bars to display temp, oil pressure, etc and hours.
I looked at my manual for a 763 and the BOSS documentation does not indicate there is an 'INPUT' error message.

 

[newty]

According to the Bobcat Historical Specs the 751G series started in 1999. Does you machine have the newer rounded cab and triangular headlights and dash is LCD black letters on grey background?
The BOSS option has a dash panel on the right side of the cab with orange icons and vertical bars to display temp, oil pressure, etc and hours.
I looked at my manual for a 763 and the BOSS documentation does not indicate there is an 'INPUT' error message.

Hi, Your correct it is a 751G with the newer cab and triangular lights. A bit more information. Turn ignition on and beeps once and ignition lights come on for a second then shown INPUT. If i remove and replace the fuse for the computer a few times the hour clock will show the hrs then fault code 32-37 (lift actuator wiiring fault). The machine will not start off the ignition. If i cross the starter and hold stop lever on the fuel pump open I can drive the machine but not raise or tilt (due to wiring fault) but this must be the second fault?? Bobcat want to plug it in to diagnose. Thanks

 

[Tazza]

Hi, Your correct it is a 751G with the newer cab and triangular lights. A bit more information. Turn ignition on and beeps once and ignition lights come on for a second then shown INPUT. If i remove and replace the fuse for the computer a few times the hour clock will show the hrs then fault code 32-37 (lift actuator wiiring fault). The machine will not start off the ignition. If i cross the starter and hold stop lever on the fuel pump open I can drive the machine but not raise or tilt (due to wiring fault) but this must be the second fault?? Bobcat want to plug it in to diagnose. Thanks

There is a solenoid that locks out the lift and tilt for safety reasons. It will not un-lock if the controller believes you are not in the seat with the seat bar down. I wouldn't think this is your primary fault causing the machine to not even start.
It may actually be an idea to get bobcat to hook up a lappy to it, they will find the fault much faster. You will need to jump the lift and tilt lockout solenoid though and jump the starter to get it on a truck/trailer to get to the dealer. Not sure what they want to come and do an on-site visit.....

 

[skidsteer.ca]

There is a solenoid that locks out the lift and tilt for safety reasons. It will not un-lock if the controller believes you are not in the seat with the seat bar down. I wouldn't think this is your primary fault causing the machine to not even start.
It may actually be an idea to get bobcat to hook up a lappy to it, they will find the fault much faster. You will need to jump the lift and tilt lockout solenoid though and jump the starter to get it on a truck/trailer to get to the dealer. Not sure what they want to come and do an on-site visit.....

If its like my 773 G, In with your fuses are spdt relays (1” square cube with 5 blade terminals comining from it) try swapping the starter one with some other function.
Ken

 

[Lseven]

If its like my 773 G, In with your fuses are spdt relays (1” square cube with 5 blade terminals comining from it) try swapping the starter one with some other function.
Ken

Hi, first post and sorry to bump an old thread. I have much the same problem on a '06 S160. The thing only has 400 hours on it. The issue started occasionally last winter but now seems dysfunctional. A heater in the cab for a while seems to fix it but last night I left it in the heated shop and it's still going this morning. More details; Normal start beeps when I turn the key, all the panel lights come on briefly then the display goes to glow plug countdown. I used to be able to start with door open and the lap bar up. Lately I've been closing the door lowering the lap bar and engaging the park brake and that seemed to help. Current start is no beep or lights and then 'input' displayed and then power goes to heater fan and panel lights but no glow plug and will not engage starter. Turning the key multiple times sometimes the panel lights come on briefly, sometimes 'input' never shows up and eventually it may just kick in fine. The colder it is the less likely this is to happen. Once it starts and is warm then no problem restarting. One thing I notice is when it starts I hear a couple of relays 'click' that sound to be around the bottom of the door. (They may be in the panel under the seat). No start has no sound of relays clicking. I am going to try the suggestions here but just looking for a bit more guidance to figure out which one it might be. Eventually I will phone the dealer but they are a ways away, generally crooks and mostly not that helpful. I'm guessing a moisture problem as mentioned hence the cab heater helping, just not sure how to track down the exact spot. I'm sure the dealer would be happy to blow through $2k in parts/labour before admitting they don't have a clue and charging me any way.

 

[Lseven]

Hi, first post and sorry to bump an old thread. I have much the same problem on a '06 S160. The thing only has 400 hours on it. The issue started occasionally last winter but now seems dysfunctional. A heater in the cab for a while seems to fix it but last night I left it in the heated shop and it's still going this morning. More details; Normal start beeps when I turn the key, all the panel lights come on briefly then the display goes to glow plug countdown. I used to be able to start with door open and the lap bar up. Lately I've been closing the door lowering the lap bar and engaging the park brake and that seemed to help. Current start is no beep or lights and then 'input' displayed and then power goes to heater fan and panel lights but no glow plug and will not engage starter. Turning the key multiple times sometimes the panel lights come on briefly, sometimes 'input' never shows up and eventually it may just kick in fine. The colder it is the less likely this is to happen. Once it starts and is warm then no problem restarting. One thing I notice is when it starts I hear a couple of relays 'click' that sound to be around the bottom of the door. (They may be in the panel under the seat). No start has no sound of relays clicking. I am going to try the suggestions here but just looking for a bit more guidance to figure out which one it might be. Eventually I will phone the dealer but they are a ways away, generally crooks and mostly not that helpful. I'm guessing a moisture problem as mentioned hence the cab heater helping, just not sure how to track down the exact spot. I'm sure the dealer would be happy to blow through $2k in parts/labour before admitting they don't have a clue and charging me any way.

Sorry I used several paragraphs on my post but they didn't show up. No 'edit' function here either it looks like.

 

[Lseven]

If its like my 773 G, In with your fuses are spdt relays (1” square cube with 5 blade terminals comining from it) try swapping the starter one with some other function.
Ken

Just to update. I have had the relays pulled and switched some around. They look to all be identical (part number and schematic on case). This didn't seem to change much. I opened up the most likely problem relays and found no sign of corrosion or staining or moisture of any sort. I also took the panels off up top and found no bare wires or such. I did find 2 switches that had quite a bit of the connectors exposed which seemed odd and poorly planned. I wiggled those in as tight as I could. I had one headlight loose in it's housing and seated that properly again. That could well of been allowing some moisture into there although I saw none. It now seems to start a lot more often (every 2nd or 3rd turn of the key) but not perfect by any means. This could be because of working connections or being in the shop drying for a couple of days. Hard to say. That loose headlight and moisture may have been much of the issue I'm thinking/hoping.

 

[Tazza]

Just to update. I have had the relays pulled and switched some around. They look to all be identical (part number and schematic on case). This didn't seem to change much. I opened up the most likely problem relays and found no sign of corrosion or staining or moisture of any sort. I also took the panels off up top and found no bare wires or such. I did find 2 switches that had quite a bit of the connectors exposed which seemed odd and poorly planned. I wiggled those in as tight as I could. I had one headlight loose in it's housing and seated that properly again. That could well of been allowing some moisture into there although I saw none. It now seems to start a lot more often (every 2nd or 3rd turn of the key) but not perfect by any means. This could be because of working connections or being in the shop drying for a couple of days. Hard to say. That loose headlight and moisture may have been much of the issue I'm thinking/hoping.

'input' i remember as being a possible panel problem.... Its been a while since i heard about it, but it rings a bell from an older post, older as in a year or two now.

 

[bobcats-for-sale.com]

Just to update. I have had the relays pulled and switched some around. They look to all be identical (part number and schematic on case). This didn't seem to change much. I opened up the most likely problem relays and found no sign of corrosion or staining or moisture of any sort. I also took the panels off up top and found no bare wires or such. I did find 2 switches that had quite a bit of the connectors exposed which seemed odd and poorly planned. I wiggled those in as tight as I could. I had one headlight loose in it's housing and seated that properly again. That could well of been allowing some moisture into there although I saw none. It now seems to start a lot more often (every 2nd or 3rd turn of the key) but not perfect by any means. This could be because of working connections or being in the shop drying for a couple of days. Hard to say. That loose headlight and moisture may have been much of the issue I'm thinking/hoping.

Any more updates on the situation?

 

[Lseven]

Any more updates on the situation?

I have been parking the bobcat in the shop every night and cannot judge cold starts now. I will say that it has slowly and steadily improved while in the shop. Whereas even in the shop at first it might have taken 4 or 5 turns of the key for everything to kick in, it now seems to go first try every time. Occasionally I would not get the hand or foot control switch to engage and would have to restart that also hasn't been a problem for several starts now. I really think the moisture is/was the issue and it is slowly drying out fully and functioning properly again. Of course I'm still afraid to leave it out and rely on cold starts as I don't know if or how long condensation will build enough to cause a problem again.

 

[Lseven]

I have been parking the bobcat in the shop every night and cannot judge cold starts now. I will say that it has slowly and steadily improved while in the shop. Whereas even in the shop at first it might have taken 4 or 5 turns of the key for everything to kick in, it now seems to go first try every time. Occasionally I would not get the hand or foot control switch to engage and would have to restart that also hasn't been a problem for several starts now. I really think the moisture is/was the issue and it is slowly drying out fully and functioning properly again. Of course I'm still afraid to leave it out and rely on cold starts as I don't know if or how long condensation will build enough to cause a problem again.

And on it goes. Yesterday must have had to turn the ignition at least 20 times to get it to kick into the glow plug countdown. It has been parked indoors, had little use of late and it has been bone dry around here. The thing has less then 400 hours on it. It is very frustrating to have to treat it so gingerly and hope it runs.

 

[Tazza]

And on it goes. Yesterday must have had to turn the ignition at least 20 times to get it to kick into the glow plug countdown. It has been parked indoors, had little use of late and it has been bone dry around here. The thing has less then 400 hours on it. It is very frustrating to have to treat it so gingerly and hope it runs.

I'm wondering if the temperature sender to tell the glow timer to count down is not working correctly.

 

[Lseven]

I'm wondering if the temperature sender to tell the glow timer to count down is not working correctly.

It's not really just the glow plug although I sort of implied that. What happens is I don't get the usual beep on start up and then the display and regular lighting. What I get is brief illumination of sensor lights and then nothing but after a moment the cabin fan will kick is so that circuit is getting power. Sometimes all the lights flash which I think is the norm and other times just a couple of them light. Eventually I get the beep and countdown display which will show 9 seconds if it's warm out and 30 for cold. I think the beep and display lighting indicates that circuit is energized as opposed to no power probably to the glow plug sensor or display or anything when there is no beep. So I'm not sure which circuit or relay is causing the problem. I have done some switching of relays but my guess is the bad relay in numerous positions could cause the same problem. Then of course is the possibility of the main brain failing to energize the startup circuit. I really don't want to have to drag this thing in to the crap dealer I have here.