JD 755 fuel injector pump

[Cocobean]

Greetings All,
My jd 755 suddenly refuses to start. I致e bled the fuel lines out to the injectors, pulled the injector lines off the top of the pump and hardly getting anything there. I知 thinking that should be a high pressure stream, is that correct? Would the pump suddenly go bad? I ran the tractor a week ago without problems. I致e done all repairs to the tractor for years, is the pump a project I can take on myself? I did a quick search and didn稚 see a replacement pump available online. Any help or info would be great appreciate. Thanks!

 

[Egon]

Does the engine turn over?

Is there a solenoid on the injection pump that goes click when the key is turned?

 

[Cocobean]

Thanks for the reply. Yes, it痴 turning over strong with a fresh battery. Fuel solenoid seems to be operating fine. I知 getting lots of fuel all the way to the injection pump, just not getting any out to the injection lines.

 

[unimog_jason]

Couple thing to check for:

- fuel filter state
- health of lift pump
- state of suction hose in fuel tank

If the fuel filter picked up a big chunk of garbage at the bottom of the tank, that could restrict fuel flow.

I had the electric pump on my 755 go bad resulting in low power and stalling at times.

The tank has a rubber hose section at the bottom that falls off over time, I know with my 755 the lower 1/4 of the tank can't be used since mine has fallen off. Make sure you're tank is full.

A couple quick checks I would do, turn the key, listen for the clicking of the lift pump. If you can hear the lift pump, crack the bleeder on the top of the filter housing, if everything is working correctly you should have a heavy flow clear of bubbles.

If that test passes, go to the injection pump and crack the bleeder screw on the inlet banjo bolt and look for the same kind of flow.

If you are getting weak flow at the filter housing, I'd suspect the lift pump. If you're getting low flow at the pump, I'd look at the filter.

If neither of those appear to be at fault, I'd start looking at the injection pump next.

Jason

 

[Cocobean]

Thanks Jason. Yes, I bled the lines and have plenty of fuel flow all the way to the injection pump. Pulled the lines off the top and not really getting anything there. What kind of job is it to replace that pump?

 

[Egon]

The solenoid on the injection pump activates the fuel pump. It does not shut off the fuel supply.

 

[thepumpguysc]

Remove the solenoid & stick your finger in the hole to see if u can move the control rack..
Have your throttle in the WIDE OPEN position.. & use your finger to mimic the sol. movement..
I'll write u a prvt msg..

 

[Cocobean]

Thanks for the message. Solenoid seems to have full movement when starting. I’ll check it again tomorrow.

 

[thepumpguysc]

I dont pay attention to tractor models so I did alittle research..
It looks like the solenoid is "external".??
I thought it was "internal".. hence the "stick your finger in the hole" line..

 

[Cocobean]

Yes, the solenoid is external and can be seen operating as the starter is engaged. The engine is a Yanmar 3tna72uk.