Tractor won't cut off.

[louiedog]

I have a 1983 JD 302 industrial tractor with a 50 hp 3 cylinder diesel. The engine would not
run at a constant RPM and would fluctuate between 12 - 17 RPMs. I usually do not run the engine at a high RPM (over 20-25)so I was thinking it was getting clogged somewhere. I let the engine run for about 5 minutes at 20 RPMs and that seemed to smooth out the engine. The next day the engine seemed to be running normally until I went to shut the engine off. The engine kept running with the key in the off position. I turned the throttle level all the way down and after a few minutes the engine slowed to a stop. Does anyone know what is wrong? Thanks

Louiedog

 

[Recoveryhill]

I don't understand your RPM numbers so I'll assume you mean 1,200 to 1,700 and 2,000 RPM's.

On a diesel with a key switch, the key functions to stop fuel to the engine by operating a solenoid valve. Key on, solenoid open, fuel flows, starter motor turns it over, compression and ignition. Turn the key off, solenoid closes and engine stops. Diesels can scarf fuel such as crankcase oil under certain circumstances and do what's called "running away". RPM's build with unlimited source of combustable liquid until the engine blows but it's unlikely what you describe is anything related to that.

You say you turned the throttle all the way down and it kept running. Did the RPM's reduce to idle, when you throttled back or did it maintain higher RPM's? If you turned the key off and it was getting diesel fuel and not engine lube or hydraulic oil, the solenoid valve is not closing which could be electrical or mechanical. If you reduce throttle and RPM's don't follow, you have another problem possibly the throttle linkage. To have linkage issues and solenoid issues is possible, it's called bad luck!

I'd check the fuel line from tank to injector pump and change the filter if you haven't already done so. I'd energize the solenoid and see if it is opening and closing properly, you could use a jumper to provide power so you could observe. I'd trace the throttle linkage, lubricate and check for movement from throttle to pump.

Someone lese here may have another take but that's what I'd look for.

 

[Tx Jim]

Sounds as if the governor drive ring in the inj pump is bad. Inj pump needs to be renewed with some good parts before you find a piston connecting rod protruding from the engine block..

 

[louiedog]

Thanks! I will check the solenoid and linkage. I have experienced the RPMs not reducing when the throttle is reduced. This happens sporadically.

 

[louiedog]

Would the governor drive ring prevent the engine from shutting off or would a bad governor drive ring not allow a constant RPM?

 

[SPYDERLK]

Would the governor drive ring prevent the engine from shutting off or would a >> bad governor drive ring not allow a constant RPM? <<

This.

 

[Tx Jim]

Would the governor drive ring prevent the engine from shutting off or would a bad governor drive ring not allow a constant RPM?

YES bad governor ring can do as you stated

 

[Recoveryhill]

Sounds as if the governor drive ring in the inj pump is bad. Inj pump needs to be renewed with some good parts before you find a piston connecting rod protruding from the engine block..

Good Call.

From Oliver Diesel: "In addition to the housing pressure cold advance (HPCA) solenoid, there is a fuel shut-off solenoid (front terminal connected with a pink wire) located inside the pump housing cover that stops the engine by cutting off the fuel flow.

The fuel shut-off solenoid moves the governor linkage, which in turn rotates the metering valve.Shutoff solenoid in housing (top) engaging the shutoff rack on top the hydraulic head. To the left of the hydraulic head is the governor assembly

When the ignition is off, the solenoid is no longer energized and the return spring pulls the shut-off rack to the "OFF" position, which through the governor linkage rotates the metering valve to cut off fuel.

The minimum/maximum engine speed governor, located under the governor cover maintains idle speeds under varying engine loads and limits the maximum speed of the engine.

The governor assembly comprises weights, the governor arm, low idle spring, idle spring guide, main governor spring, main governor spring guide, and the guide stud.

Governor weightsThe governor weights are rotated by the drive shaft. Their centrifugal force controls the metering valve at minimum and maximum engine speeds.

At idle speed, the governor weights don稚 exert much force, so the spring on the governor keeps the metering valve nearly closed.

At high engine speeds, the centrifugal force of the governor weights moves a pivot arm, compressing the spring, and rotating the metering valve to an almost closed position.

At engine speeds other than idle or maximum, the driver directly controls the metering valve through the accelerator/throttle linkage. At those engine speeds the force of the governor weights and the governor spring tension are balanced, so that neither can influence the metering valve.

A pressure regulator protects the transfer pump from excessive output pressure caused by high engine speeds or because of a restricted fuel return line.

When the valve is closed during normal operation, the valve spring holds the piston forward, blocking the regulating slot in the valve thus rendering it inactive.

As output pressure increases, the valve opens. High-pressure fuel pushes the valve piston, which compresses the spring. If the pressure is high enough to overcome the spring痴 force, the piston will be pushed back, uncovering the regulating slot in the valve. This will allow fuel to flow back to the input side of the pump, thus relieving output pressure."

And....The Guy Who Changed Everything Diesel:

http://files.asme.org/asmeorg/Communities/History/Landmarks/10001.pdf

 

[Tx Jim]

Recoveryhill
Please explain this statement From Oliver Diesel: "In addition to the housing pressure cold advance (HPCA) solenoid"???

There's no cold advance solenoid on JD 302 that I'm aware of.

 

[Recoveryhill]

Tex,

That wasn't posted as JD specific information. It was posted to help explain Rotary Distributor Diesel Fuel Injection Pumps, which from Mr. Roosa's invention, all modern mechanical fuel pumps were derived, including JD's. I picked up the article where it began discussing the shut off solenoid and governor. Mr. Roosa's Stanadyne pump offered among other features, various timing options for engine manufacturers, cold advance being just one. I might add that recent advances in Fuel Injection have again changed the rules and the newest electronic systems are quite different.

Link to the full article: Oliver Diesel - Engines & Outdoors

Louiedog: It seems that the fuel shut off solenoid and the governor are holding hands. I now see more clearly how the two problems you have, failure to shut off, and un-commanded RPMs could easily be related. Sounds like rebuild or replace time, for your fuel pump.

 

[Tx Jim]

Recovery
I'm just trying to keep the info correct for the model of tractor that was inquired about. Sometimes too much info "muddies the water" IE confuses people!!!
Jim

 

[Recoveryhill]

Tex,

Thanks for your concern for the JD community that has identical Tractors. Whether or not a Rotary Distributor Fuel Injection Pump has Housing Pressure Cold Advance (HPCA) Solenoid doesn't mean a thing to the OP's issue. I'll stand by my compliment for you calling out the pump governor. The governor only controls Idle and Max RPM, everything in between is Operator Throttle commanded. I didn't understand the linkage between the shut off solenoid and the governor, but now I do and I can only hope anyone else that is curious does, as well. The OP's problem with not returning to idle when Commanded and failure to Shut Down when the solenoid is de-energized is better understood, for Red, Orange, Green and Yellow tractors above and below the Mason Dixon Line, even Way Below That Line!

I also hope that at least "someone" appreciates the contribution of Mr. Roosa, the inventor of the Rotary Pump that changed the powering of all farm tractors, everywhere for decades. Now all we need to do is learn and understand Electronic Common Rack Fuel Injection.

"The mechanical fly-weight governors of inline and distributor diesel fuel injection pumps used to control fuel delivery under a variety of engine loads and conditions could no longer deal with the ever increasing demands for efficiency, emission control, power and fuel consumption. These demands are now primarily fulfilled by the Electronic Control, the system which provides greater ability for precise measuring, data processing, operating environment flexibility and analysis to ensure efficient diesel engine operation. The EDC replaces the mechanical control governor with an electro-magnetic control device."

Texas probably doesn't like that, would be my guess?

 

[Tx Jim]

What the heck has common rail got to do with the original question? NOTHING and you're muddying the water again.
Jim

 

[Recoveryhill]

What the heck has common rail got to do with the original question? NOTHING and you're muddying the water again.
Jim

Sorry Tex, I don't equate detailed information with muddy water.

Was it a bad thing to trace diesel fuel injection from inline pumps to rotary pumps and then mention electronics? Was it a bad thing for me to express my own education on how the OP's problem could be the fuel pump, as you stated, and not the delivery system or throttle linkage as I incorrectly guessed?

It is not my intention to confuse anyone, if that's what you mean by muddy water. I still don't see how posting detailed information on a rotary pump and it's magnificent inventor and pointing out how the OP's problem was likely the pump according to the explanation in the Oliver article would confuse anyone. If there is confusion it's mine, with your comments which I truly don't understand.

My understanding of these forums is that they are a free flow of information, corrected by others when necessary, all adding up to increased knowledge of how machines work and what is possible and impossible with them. Sorry if I didn't adhere to what seems to me to be a very narrow interpretation of that mission for the forum. Opinions also have a place here, and while I respect yours, and have expressed my own in the past, I feel justified in defending my providing what I thought was both interesting and instructive information on injection pumps.

Peace

 

[Tx Jim]

Recoveryhill
You can make all the excuses you chose but "common rail" and a JD 302 have only one thing in common. They both utilize diesel for fuel but nothing else. Have a wonderful day!
Jim

 

[skyhook]

Sounds as if the governor drive ring in the inj pump is bad. Inj pump needs to be renewed with some good parts before you find a piston connecting rod protruding from the engine block..

I agree with this,
even though the fuel shut-off is working as it should,
if fuel is still "slipping by" you need to have your injection pump checked.
It's giving you a warning sign, a runaway diesel is not a pretty site, been there, done that.

 

[louiedog]

I want to thank everyone for the help. I priced a remanufactured fuel injector pump at $1,000 with a $200 core. So the total will be $800. Does that sound correct? Never had a diesel before. I will be changing the pump myself as I have no trailer and afraid to start the engine to lift the F E L. Is it difficult to time the pump with the engine? I was told the pump will come timed to T D C of the #1cyclinder and I have to retime the engine. Would there be a good manual you would recommend? Thanks again.

 

[john_bud]

May not apply here, but my kubota won't shut off when the battery is really weak. The solenoid to shut the fuel can't engage, I'm guessing due to low Volts? Anyway, it was pretty confusing and a bit scary at first! But a new battery and all was well.