Stanadyne injector problems

[markreaver]

My JD 500C has sat for 7 yrs and now the injector pump will not pump fuel out the top. It is getting 12 volt to it. I took the cover off and put 12 volts to the solinoid and it clicks in, but then nothing else. Is this correct or shoud it go in and out on its own? I then took off and broke 1 of the 4 top screws. Any idea where I can get one? Thanks

 

[Billy Shafer]

If it has had water in the fuel. The valves may be rusted shut. Did you remove the bleed screw on the side of the pump. May have an air lock. You could try a hardware store for the screw.Take one with you to match up.

 

[Bob]

It NOT so important that it pumps fuel out the top return fitting right away.

What's important is that it pumps fuel to the injectors.

Once the pump is purged of air and the engine is running the fuel will begin to come out the return line.

Incidentally, the shutdown solenoid you are fascinated with DOESN'T control the fuel being returned out the top fitting but rather controls the metering valve that meters fuel into the "hydraulic head" where it then is pumped by the plungers out to the injectors.

Since you have the top off, have you verified the metering valve is free to rotate?

If it is free and you have fuel TO the pump the vane-type primary pump may not be working.

The other likely culprit is that the pumping plungers sometimes become stuck in the retracted position by vanish/gunk/rust during a period of non-use. If stuck in the retracted position they will not be able to take on a charge of fuel for each upcoming injection event and no fuel will be pumped to the injectors.

Another thing... are you SURE the injection pump internals are rotating... if the hydraulic head has seized the pump driveshaft has a "necked down" area that will break to protect the timing gear train and pump from further damage.

 

[markreaver]

Thanks for the information. Yes, I ran the engine on ether for 2-3 mins with the bleeder open and the injector lines loose, but no luck.

No, I have not checked to see if there is top rotation, but I will do that and check as far down as I can without messing the parts up. This tactor was parked because fuel was going into the oil pan. I had a new butterfly(?) seal installed to stop that problem, but just can't get the fuel out of the bleeder or upwards.

I am afraid to send the pump out and then get a bill for $500 - $1,000. Thanks again guys.

 

[Billy Shafer]

The only way I know your pump can dump fuel into the oil. Is if the shaft seals fail. Not sure what a butterfly seal is. You could also have a bad lift pump. I would remove the fuel supply line and make sure you are getting fuel to the pump. I think that pump also has a filter in the supply intake side.

 

[markreaver]

OK Thanks for your help.