Maybe a question for Dieseltech

Tractorcedric · Dec 17, 2017

So I have a 3020 that has been in a barn for a dozen years with out being started. I can get fuel to the bleed screw in the cover of the injection pump. I have cranked it a lot but still have no fuel at the injectors. I suspect that the plungers are stuck. Is there some way to free them up without taking the pump apart?

JDEM · Dec 17, 2017

Yes. You can hook compressed air to one of the discharge ports and rotate the pump until that port is in inject position for that cylinder. Air will back feed and pressurize the two pump-plungers. I would be more apt to think the fuel metering valve is stuck - assuming you are sure the pump is actually turning and the driveshaft is not broken.

cushman · Dec 17, 2017

If you try to start it with a stuck metering valve,you need to find a way to choke the engines air intake. If the metering valve is stuck open,you could have a runaway engine.

Dieseltech · Dec 17, 2017

First, try what JDEM said, if you are lucky it MIGHT free up mildly stuck rotor plungers. Most I see in that set awhile plungers are stuck so tight they have to be driven out with a brass punch. When they are that bad metering and delivery valve will be stuck too. Any traces of water in the fuel, they will be stuck tight. I had a couple pumps in last summer there was so much slimey rust buildup inside the weights were even stuck in the cage. Did work fine after a complete tear down and cleaning though. Just hope the drive shaft and hydraulic head are OK. If head is seized and shaft broken, best try to find another pump. I might have a good used head on the shelf though.

Al Baker(pumpman) · Dec 17, 2017

how does this air get past the delivery valve?

Dieseltech · Dec 18, 2017

Very Slowly, same as when air timing any Stanadyne pump. The valve is more like a controlled restriction, not like a one way type valve like inline pumps use.

Al Baker(pumpman) · Dec 18, 2017

If the air back feeds through the delivery valve slowly then it is now acting like an orfice. Wouldnt this cause a pressure drop in the air? Shop air starting out at 150 psi then dropping even a little isnt much force on them pistons. I have resealed at least a hundred froozen pumps in the last few years. Very common problem. Maybe 30-40% of all the pumps I see. Most are stuck where a small hammer and punch after soaking are needed to bust them plungers loose. I dont think I would bet much money on the air idea. Sure isnt going to hurt to try. If it did do something it isnt going to help the metering valve at all. Loose plungers with a stuck metering valve is a receipe for a run away engine. I think I will stick to my old school bench repair. Al

JDEM · Dec 18, 2017

The original poster DID ask about something he could try without taking the pump apart. Using air certainly works in some situations. Sounds obvious to me that you have never air-timed and engine. You can hear the two rollers jump out pretty good with 120 PSI of air.

Al Baker(pumpman) · Dec 18, 2017

Well its safe to say I have done one maybe,Was on my first day though. Never tried it on a tailgate though. I only can speek from experiance. Experiance I got from MY OWN shop where a mistake made cost ME money. Not the company. When things go right thats great, but if they dont someone has to pay the price. I NEVER post anything unless I am sure it will work. Never a guess. Do you ever post your real name and phone contact so if things go wrong someone can hunt you up? Al

Maybe a question for Dieseltech

Tractorcedric

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JDEM

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cushman

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Dieseltech

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Al Baker(pumpman)

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Dieseltech

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Al Baker(pumpman)

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JDEM

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Al Baker(pumpman)

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