Fuel pump trouble shooting

[old sparky]

I have a B7100 that I cant get running after running out of fuel. I cant get a solid fuel, air bubles are always there. So to prove my fuel pump is good or bad. Can I bypass my pump with a electric pump? To see if my pump is bad?

thanks,

 

[Peter 315]

Yes you can but are you sure all the fuel filter gaskets are on correct?

 

[old sparky]

no, My fuel assembly was leaking and I couldnt get the filter out. So I bought a new assembly and just bolted it on. bleeding of corse. I have tried getting it running and think I just about got it then it slows rpms. Then I try bleeding while running and usually make it worse, then it dies. I think I have a electric fuel pump in the garrage and thought I may put it on to try?

 

[rScotty]

I have a B7100 that I cant get running after running out of fuel. I cant get a solid fuel, air bubles are always there. So to prove my fuel pump is good or bad. Can I bypass my pump with a electric pump? To see if my pump is bad?

thanks,

No you can't use an outside pump. Diesel fuel pumps are special. They take in a constant flow of fuel from the fuel filter assembly and as the motor turns the diesel fuel pump sends fuel to the injectors in a timed pulse at several thousand PSI. That pulse of fuel opens the injector and sprays a little fuel into the combustion chamber at just the right time to meet the piston coming up on the compression stroke.

So a diesel fuel pump - called an "injector pump" has almost nothing in common with a low pressure constant flow electric pump.

What you are seeing is very probably a poor connection in the fuel line between the fuel filter assembly and the diesel fuel pump that is allowing air to be sucked into the fuel line. Maybe so/maybe no...but that is a common problem and gives the exact symptoms you are seeing. Running a diesel out of fuel can be a hassle that has you believing all sorts of crazy stuff, but it is almost always a bad connection in either the fuel lines or the fuel filter bowl that is putting an air bubble into the fuel line.
good luck,
rScotty

 

[Agvg]

If it starts you have an issue with fuel delivery, remove and inspect al pipes and fittings from the tank to the pump, and check if there are a strain in the tank it self.

 

[old sparky]

FYI. The problem is the fuel pump. The low pressure pump that supplies the injector pump is bad. After getting to it. I saw it was leaking, so it was sucking air also. I bypassed it with the electric pump, bleed the lines and it runs and accelerates as it should. I will get a pump ordered. Would there be a problem running an electric pump permanently? I ordered a replacement but wonder?

thanks

 

[PILOON]

Permeant electric, no I don't think so. Often a cure for many similar situations.
BTW, that is a 'lift pump'.

 

[Peter 315]

FYI. The problem is the fuel pump. The low pressure pump that supplies the injector pump is bad. After getting to it. I saw it was leaking, so it was sucking air also. I bypassed it with the electric pump, bleed the lines and it runs and accelerates as it should. I will get a pump ordered. Would there be a problem running an electric pump permanently? I ordered a replacement but wonder?

thanks

The newer tractor have a electric transfer pump ,lift pump , what ever you want to call it......