Tractor dies intermittantly

[CalG]

Why lug it down to shut down, There is a manual fuel cut off lever right on the fuel pump.

 

[airbiscuit]

Sounds like you have figured it out, but I will add another thought for the good of the order. I had a friend who had a diesel tractor with intermittent stopping issues. It turned out top be bacterial growth in his fuel. Now he puts a fuel treatment in his tank top prevent organic growth. Sounds crazy, but something to think about.

 

[davemhughes]

Why lug it down to shut down, There is a manual fuel cut off lever right on the fuel pump.

Last year I replaced the fuel pump. OEM replacement was $500 so i went with a $20 universal, no fuel shut off. Earlier I just reconnected the wire and turned the key off....

Sounds like you have figured it out, but I will add another thought for the good of the order. I had a friend who had a diesel tractor with intermittent stopping issues. It turned out top be bacterial growth in his fuel. Now he puts a fuel treatment in his tank top prevent organic growth. Sounds crazy, but something to think about.

Last weekend i completely drained and cleaned the tank and filter. Good thought, thanks.

 

[CalG]

Last year I replaced the fuel pump. OEM replacement was $500 so i went with a $20 universal, no fuel shut off.
.

The pump you replaced was the lift pump that feeds the high pressure injector pump.

Look carefully on the right side of the engine for a lever with a hole in it's free end. It is arranged vertically with the free end down. It is just to the front of the silver Mitsubishi engine identification label affixed to the side of the engine block, in fact, it partially obscures the ID plate.

 

[davemhughes]

Injector Pump....got it. I will look at it tomorrow after work.

 

[CalG]

I can say with certainty that disconnecting either wire to the fuel cut off solenoid overcomes the random shut off difficulty.

I was able to chip and shred most of the day without interruption after having two undesired shut downs in less than an hour this morning.

The manual fuel cut off shuts the engine down when back in the shed. I suppose I should run a control rod to the operator's station just to provide some sense of safety. There are likely times when shutting down the engine would be the desired response to some types of misadventure.

 

[Richard]

Sounds like everyone is up & running. I'd like to offer another item to contemplate to a casual reader that might have a similar problem in the future.

In my case, it's a backhoe/loader. Machine would start & run like a watch.... I'd get going to do something and it would die. Would NOT start for the life of me....then...20 minutes later, fires right up like nothing ever happened....go to do something and it would die, repeating the process all over again.

I could "idle" it down the road a mile but shortly after I start flexing it, it would die and take a while before it would start up again.

Long story short.... I have not one but two water separators....

The lower unit was full of water, essentially cutting the fuel. I guess after it sat a few minutes, some fuel would dribble past it enough to start/idle the machine but when I start working it, it would starve.

Drained water, replaced filter and all is well.

I literally stumbled onto that "fix" after scratching my head for maybe a week or so on other ideas.

 

[DieselBound]

Regarding fuel shutoff solenoids, many times it's the wiring that's the culprit. As everything ages wiring is one of the primary points of failure: insulation breaks down, wires start breaking etc.. Good troubleshooting practice is, as has been mentioned, to bypass the stock power wire to the solenoid. If you've got a good 12v to the solenoid then any issues are going to be with the solenoid (or something else- also quite possibly wire-related [IP wire harness]). The clicking sounds are pretty telling: there shouldn't be any unless the operator has switched the key.

 

[CalG]

Regarding fuel shutoff solenoids, many times it's the wiring that's the culprit. As everything ages wiring is one of the primary points of failure: insulation breaks down, wires start breaking etc.. Good troubleshooting practice is, as has been mentioned, to bypass the stock power wire to the solenoid. If you've got a good 12v to the solenoid then any issues are going to be with the solenoid (or something else- also quite possibly wire-related [IP wire harness]). The clicking sounds are pretty telling: there shouldn't be any unless the operator has switched the key.

Of course the advice to check for "good solid 12V to the solenoid" DOES NOT APPLY to the SAME configuration where the solenoid is OPEN to fuel flow when it is NOT ENERGIZED. This little detail can cause confusion in the diagnostic process.

 

[DieselBound]

I toss out the "energized" altogether. You need voltage to allow fuel to flow (with a properly functioning shutoff solenoid): if there's an instance in which dropping voltage doesn't shut off the fule supply then I suppose I'd like to hear/know of it. What I was trying to introduce here is that the wires themselves are often the culprit: folks can chase their tails around and then come back to find a broken wire which will flex "open" (dropping voltage) when operating (yet be perfectly fine when just sitting there)- wires will tend to break down at connectors or near a point where a wire harness goes from a fixed route to a flex area (wire unsupported); check resistance while messing with the wire(s), or, just completely bypass (with the fuel shutoff solenoids they tend to a simple single wire affair, so bypassing is a quick way to chop the problem in size).

 

[CalG]

I toss out the "energized" altogether. You need voltage to allow fuel to flow (with a properly functioning shutoff solenoid): if there's an instance in which dropping voltage doesn't shut off the fule supply then I suppose I'd like to hear/know of it. What I was trying to introduce here is that the wires themselves are often the culprit: folks can chase their tails around and then come back to find a broken wire which will flex "open" (dropping voltage) when operating (yet be perfectly fine when just sitting there)- wires will tend to break down at connectors or near a point where a wire harness goes from a fixed route to a flex area (wire unsupported); check resistance while messing with the wire(s), or, just completely bypass (with the fuel shutoff solenoids they tend to a simple single wire affair, so bypassing is a quick way to chop the problem in size).

DB
You obviously don't have knowledge of how the Mitsubishi fuel cut off system works. The Fuel Cut Off Solenoid is energized through a control module ONLY FOR SEVERAL SECONDS AFTER THE KEY SWITCH IS TURNED TO OFF.
If the Solenoid were energized during running operation, it will self destruct by over heating. The current draw required to close the valve is that high. NO VOLTAGE/Current is required to allow fuel to flow, even with a properly functioning shut off solenoid.

The timer and "electro-magic" is in the control unit. A small plastic "black box" fixed to the fire wall.

Peculiar perhaps, but read the entire thread for details. I've copied and pasted text from the service literature.

 

[DieselBound]

OK, thanks! I stand corrected.

More info:

http://www.tractorbynet.com/forums/...g/101444-fuel-shutoff-solenoid-hows-work.html

 

[davemhughes]

Right now unplugging the solenoid is allowing for uninterrupted use of the tractor while I am waiting for the parts to get here.

I think I am on the path to getting it fixed but but it's going to be replace a part and see type venture

 

[CalG]

I am eager to hear if it is the key switch.