Bobcat 751 wont start

[Tazza]

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.

It really seems like it could be a wiring connector issue too. The newer machines have pretty good connectors between the harnesses, but they could always get corrosion. Its almost as if the main power to the computer isn't all there.
Thats the problem with these newer machines, so much more wiring to deal with and a computer!

 

[Lseven]

It really seems like it could be a wiring connector issue too. The newer machines have pretty good connectors between the harnesses, but they could always get corrosion. Its almost as if the main power to the computer isn't all there.
Thats the problem with these newer machines, so much more wiring to deal with and a computer!

Update for my problem which was very similar to the original poster. After a summer (wet one) staying outside I seem to have no more problems. I did repair the headlamp seal that is close to where I believe the controller is mounted. Now this winter it is outside and starts consistently even down to -25 or 30. Very occasionally I may get a single 'input' message but the starts are reliable overall. It really seems it was a moisture issue near the controller. Mounting sensitive electronics behind a rubber sealed headlamp seems a bad idea but I'm sure it's a money saver in manufacture.