RepMontreal
New User
Hello everyone and thank you for reading my post. I am having a great deal of trouble with a 1980's 450B dozer. It was started and used to pull a semi out of a ditch. It ran for about an hour and a half, pulled the semi out, mowed down a few trees, and then on the way back to the barn it died in the middle of the field and would start back up but not stay running. The fuel system has been bled multiple times at the filter, injection pump inlet, and the four lines at the pump leading out to the injectors. The tank was removed because it was filled with sediment and rust. Currently I have an auxiliary tank on it. I found a leaking on/off valve for the tank and had it replaced along with the transfer pump. However, even after bleeding it with the aux tank, it still starts and dies after awhile. If I let it sit for a day, the first time I start it up it runs for a whole minute just fine. Then it progressively runs for less and less time. I've pulled the inspection cover off the side of the injector pump and saw no debris. I found out yesterday that if I crack the screw on the side of the injection pump and allow fuel to leak out of that hole, it will stay running with no issues. (Other than polluting the dirt). It's almost like it's over pressurizing, and cracking the screw on the pump relieves the excess pressure. I've blown out all the lines with compressed air and re-bled them. I do see a bit of 'aerated' fuel coming out of the 4 lines leaving the pump if I crack them (could just be high pressure), but cant seem to bleed it out. If air in the pump was the issue, it doesn't make sense to me why cracking that screw on the side would resolve it. Has anyone ever had this issue before?? It's driving me nuts. I want to pull the pump but my boss doesn't want me to get into that yet. Pics below. Thank you for all advice!!