Massey 231s Bleading Fuel Lines

[dhuhncke]

Hello I parked my 231 last fall in the shop now don't start, so far I think the fuel lift pump is shot so I have a new one ordered, since it appears the lift pump does not retain pressure to get the fuel to the injectors, pump works to pump up the fuel filter and to the full pump but when system is closed (no lines open) the lift pump has no resistance when pumping manually.

the book states to pull the plug off the fuel cutoff switch located on the fuel pump and crack the injectors to bleed air out of lines, while turning engine over.

My question is what the heck does this electric switch do? When its got power to it does it allow fuel to return back to the tank?

Thanks in advance for any insight!

 

[ddbackhoe]

Electric power opens the switch/valve to allow fuel flow. It should be allowing fuel to flow to the engine, not the tank.

 

[dhuhncke]

Thank you ddbackhoe! I presume the reason to remove power from the fuel/cutoff switch is to force the fuel to the injectors and not allow it to return to the tank when cranking the engine to purge air from the fuel pump to the injectors. I wonder how the fuel pump purges air it must not depend on the return to tank line. The book says the fuel pump is self purging.

 

[ddbackhoe]

Thank you ddbackhoe! I presume the reason to remove power from the fuel/cutoff switch is to force the fuel to the injectors and not allow it to return to the tank when cranking the engine to purge air from the fuel pump to the injectors. I wonder how the fuel pump purges air it must not depend on the return to tank line. The book says the fuel pump is self purging.

Umm, not quite. On a non-electronic diesel engine there are two ways to turn it off. Cut the fuel or cut the intake air. The key switch is usually tied to the fuel cutoff switch. Key on, fuel can flow..key off, no fuel. The fuel injector pump is what forces fuel into the injector and cylinder.

 

[dhuhncke]

Thanks ddbackhoe! its fixed! I have 3 agco books on this tractor two are wrong and one has the correct procedure bleading air out of the fuel lines! YOU are correct there should be 12volts at the fuel cutoff with the key on, I found 0 volts! looked at the fuse box very corroded wiggled some wires at the fuse box now I have 12 volts! cracked the injector unions, cranked engine till fuel spit out the unions, re-tightened unions, started right up! of all things if the **** maint. books were correct could of fixed it right away. the book says to disconnect the power to the fuel shutoff which is totally wrong!!! THANK YOU FOR YOUR HELP!