runaway rtv900 engine???????

[rtv9001]

so sadly, as the title says I all of a sudden had an issue with my rtv where it was way down on power like fuel was being restricted, so while I was trying to diagnose I started and stopped the engine a few times.
Well, on the last and final time the thing ramped up to max rpm, spewing black smoke, wouldn't shut off with the key and I eventually had to crack the fuel lines right at the injectors until it lost fuel pressure and stalled.

Hoping somebody might have some experience with this issue and could direct me to a specific part?
I'm assuming the actual high pressure pump is working fine since it ran away, so I guess whatever is supposed to meter the amount of fuel has failed? I just don't really know what part that would be on this.

 

[thepumpguysc]

The inj pump controls the amount of fuel sent to the injectors, the injectors atomize the fuel into a mist where the mist is “exploded” in the cylinder caused by the heat generated from the glow plugs and pistons going up and down..
That said, I would suspect the control rack on the inj pump is stuck wide open..
If your shut off solenoid is screwed into the left hand side of the inj pump “block”, u can disconnect it (1wire) and unscrew it from its home.
Now reach in and see if u can move the rack with your finger.. or a pick..
A lot of times there is an access cover on the engine directly on the side of the inj pump..
U can remove it and gain access directly to the control rack.. see if u can move it left and right..
Good luck.

 

[rtv9001]

so I just talked to a tech at a tractor dealer near me. He thought it sounded like it cracked a barrel in the pump?
And replacing the pump assembly itself would be the solution?
My shut off is on the right side of the pump when looking down at it, toward the front of the vehicle. I even pushed that shut off lever myself and it did nothing to cut fuel. But mine doesn't seem to have any access cover so not sure if maybe it's a different design?
It's a 2010 rtv900
I could get a picture if that would help?

 

[thepumpguysc]

A picture would be GREAT..
I wonder how many times they used THAT line.!!??

 

[rtv9001]

 

[rtv9001]

so here's my injection pump
governor, power control is on the right of this.
the top lever with the red screw is the fuel kill, which of course did less than nothing even when I manually pinned it on it's stop.
so bottom line I don't know otherwise how the fuel is controlled in this unit.
I did change an injection pump on an rtv probably 15 years ago but I do remember it's basically a rectangular canister shape that slides down into the opening to rest on 3 cam lobes that do the pumping. Other than that I don't recall much nor how you even prime one of these things without just endlessly cranking the motor

 

[Sawyer Rob]

You stop a runaway diesel by blocking the air supply, a rag works good for this.

SR

 

[thepumpguysc]

U have it correct, it’s the same as your previous job.
Bolts on the 4 corners..
U might have a slight problem if the rack is stuck, only because the rack has to be in a certain position to allow the rack pin to pass..
There’s actually a CUT OUT in the block to allow it to pass..
Do yourself a favor and watch some videos… they’re all basically the same..
Kubota has some decent ones.. your pump is called a PFR PUMP..

 

[rtv9001]

yeah I tried searching for videos and can't find crap.

bottom line, I'm assuming at this point you agree it's the pump assembly itself that has a failed part and I need to swap that whole part out?
or am I wrong and it may be something else?
I'm certainly no expert on these machines. I understand the fundamentals but I have pretty limited experience actually working on these engines. The pump is expensive as hell so I'd hate to throw that money at it and have a runaway again. However this time I'm going to have a C02 fire extinguisher ready on hand so I can stop it instantly.

 

[mike0000]

This is a D722 3 cylinder not sure how close the IP’s are to the RTV’s

 

[thepumpguysc]

If u think 500.00 for an injection pump is expensive, u bought the wrong toy..

Good find Mike..
It’s the same procedure.

FYI: they can be rebuilt..
But for not much less than buying one off Fleabay..

 

[gstrom99]

You stop a runaway diesel by blocking the air supply, a rag works good for this.

SR

I think a "run away" diesel would suck that rag right up and it'd cause more internal (stuck valves...?) damage.

 

[Sawyer Rob]

You put a rag over the intake and your hand over the rag and the diesel will choke right out, no problem at all.

If you have an air filter, a rag is not going through an air filter anyway.

SR

 

[ruffdog]

I think a "run away" diesel would suck that rag right up and it'd cause more internal (stuck valves...?) damage.

If the rag is plugging the intake before the air filter, it would have a hard time getting through that.

 

[rtv9001]

so the video looks exactly like my setup, thanks for posting that link.
my question is, That guy had a problem with a stuck "rail" that closes off the fuel, so when he tried to actuate the shut off link it wouldn't move.
But in my case that moves just fine, the key actuates it and I can move it by hand freely, but obviously it does nothing because the thing went
haywire.
So would I want to pull that pump assembly but leave the throttle/cut off assembly in place? And will the fuel rail pin clear all that? I guess I'm not understanding how that pin on the actual pump itself hooks up to the linkage that actually moves it back and forth?
And then I guess since mine moves freely there must be something internal to the pump that blew out? Possibly just one injector went wide full out?

edit, I see now how the rack pin engages that lever

 

[thepumpguysc]

It’s possible that an injector is stuck open..
But seeing u don’t have a pop tester, it could be anything.. pump, injectors, bad rings sucking oil..
U just gotta grab your wrenchs and get to work.

 

[rtv9001]

It’s possible that an injector is stuck open..
But seeing u don’t have a pop tester, it could be anything.. pump, injectors, bad rings sucking oil..
U just gotta grab your wrenchs and get to work.

fair enough
I'm pretty sure it isn't a ring blowby issue because as soon as I cracked the injector lines it died right down
I wasn't really sure how these injectors worked. I guess I assumed they just spray when the cam lobe hits the corresponding piston in the pump which would be the only time it has pressure behind it anyway. And something else meters fuel to those.
I guess at this point I may as well just pull that pump assembly and see if there's anything glaring.

Is there a procedure for priming the lines and whatnot after it's been apart or do I have to just crank it over?

 

[ruffdog]

Is it possible a seal went bad and was sucking crankcase oil?

 

[thepumpguysc]

The fuel system is a closed system.. once u break the seal (inlet line) u have to bleed the system..
The easiest is loosening the lines AT THE INJECTORS and spinning the engine until fuel squirts out and tighten.

 

[rtv9001]

so I just got the pump out
the plate that holds in the fuel rail cut off was so loose I could just thread out the 4 phillips screws by hand without a screwdriver. I'm thinking it allowed the fuel rail to skip over one or more of the injectors off that little thing that the rail keys into.

so my question is, is it safe to re-use this pump due to whatever unknown reason those screws got totally loose? If so, how do I ensure they stay tight? It covered in oil now obviously so would I clean it in a parts washer and use some type of locktite or something?
I'd rather spend the money on a new pump if there's any chance this will happen again with this one.