KUBOTA L4150 FUEL INJECTION

[JER2525]

My L4150 suddenly went dead. While it will crank over, there is apparently no fuel getting to the injectors. My first thought was a new fuel pump. That did not work. It seems as if the fuel cam shaft is not turning since no fuel comes out of the fuel pump when the discharge hose is disconnected, therefore no fuel to the injectors. Any thoughts? Thanks.

 

[brain55]

Are you sure that there is sufficient fuel flow to the injection pump via the filter and transfer pump. I have seen the petcock in the tank plug up many times, have never seen an injection pump failure where all cylinders would not get fuel. I usually pull the line off the tank and check flow there and work my way forward.

 

[rbargeron]

Yeah, if there's no fuel at the discharge of the transfer pump, it's likely the filter or the lines from the tank.

 

[JER2525]

Thanks for the reply, but I have now checked and the fuel camshaft is not turning, therefore no fuel pump pumping and no injectors pumping. Maybe a shaft key fell out of the fuel camshaft or the gear is just spinning on the fuel camshaft. I will have to take the front of the engine off to find out.

 

[brain55]

I have seen idler gears lose their teeth on smaller engines, but not the 5 cylinder. That would be my guess, have never seen a crank gear shear its key, but stranger things have happened.

 

[nightowl490]

Very interested in the turnout for this post. Any update?

 

[JER2525]

It is amazing how much has to be removed from the engine to get to the fuel cam shaft. As it was noted, the fuel cam shaft was not turning despite cranking the engine.
After I got the front engine cover off, it was noted that the fuel cam shaft gear was not engaging with the mating gear. Quick inspection revealed the failure of the front fuel cam shaft ball bearing, allowing the shaft to move and disengage the gear. replacement of both bearings on the fuel cam shaft is relatively easy, but removing all of the accessories to remove the shaft from the engine is a royal pain. Yes, I am replacing both the front and rear shaft bearings, simply because of the age on the rear bearing, and the fact that I do not want to tear the engine down this far again if I can help it.

I am also replacing the oil pump and water pump. The oil pump replacement is a preemptive move, and the water pump was definitely in need of replacement. All of this with the replacement of o rings and the main oil seal in the cover should get me running well for a long time again.

 

[brain55]

I have seen rear camshaft bearing failures but not fronts, usually the rear is discovered when the drive gear for the hydraulic pump wears through the case and creates an oil leak.