# Fuel injector pump



## pkty (Jun 28, 2019)

Hope someone has had the same problem I’m having. My Montana 3840 with a Mitsubishi S4L2 will run great for about 10 minutes then start bogging down. Suspecting injection pump failure. I’m getting the same flow of fuel after the lift pump when it looses power as before it looses power. 
I’v ruled out clogged fuel supply and return lines. Am I correct in my assumptions? Those pumps are expensive with no rebuilding kits available. Appreciate any response.


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## thepumpguysc (Jan 25, 2015)

The parts are purchased individually.. no kit.
have u tried adjusting the shut off.?? IF its electric, it may be getting weak & dropping the "plunger" which inturn is contacting the control rack giving u low power.
Just a thought.
U can click on my screen name for contact info.


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## pkty (Jun 28, 2019)

Thanks for responding. I’m new to diesels and that is a great tip to look into. 


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## thepumpguysc (Jan 25, 2015)

Prvt. msg sent.


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## pkty (Jun 28, 2019)

thepumpguysc said:


> Prvt. msg sent.


Thanks. I just might do that. Does my tractor symptoms sound like a failing injector pump? 


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## pkty (Jun 28, 2019)

No change even after removing the fuel shut off . Boggs down after 15 minutes. Can an injector pump or injector show symptoms of fuel starvation but only after 10-15 minutes?


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## thepumpguysc (Jan 25, 2015)

THAT "sounds like" a bad fuel cap.??
Loosen the fuel cap a few turns or take it off & run it.. & report back..
Have u taken a look at the filters after this happens.?? are they full or empty.??


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## pkty (Jun 28, 2019)

thepumpguysc said:


> THAT "sounds like" a bad fuel cap.??
> Loosen the fuel cap a few turns or take it off & run it.. & report back..
> Have u taken a look at the filters after this happens.?? are they full or empty.??





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## pkty (Jun 28, 2019)

It sounds and acts like it’s a fuel restriction. But I get the same fuel flow after the lift pump when it looses power as before it looses power. So I’m perplexed as to what could be going on upstream of the lift pump that would make it loose power after 10 - 15 minutes of bush hogging . I’m missing something obviously.



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## gman51 (Mar 22, 2016)

Have you checked the fuel filter? The filter might be restricted from water saturation. It could be after running a while that the filter doesn't have as much fuel in it as at first. This can cause your problem. I have seen this happen before on a 350 chevy and a 903 cummins.


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## pkty (Jun 28, 2019)

gman51 said:


> Have you checked the fuel filter? The filter might be restricted from water saturation. It could be after running a while that the filter doesn't have as much fuel in it as at first. This can cause your problem. I have seen this happen before on a 350 chevy and a 903 cummins.


Fuel flow after lift pump is the same before and after engine bogged down 



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## thepumpguysc (Jan 25, 2015)

Have U TRIED loosening/removing the fuel cap on the tank.??


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## pkty (Jun 28, 2019)

thepumpguysc said:


> Have U TRIED loosening/removing the fuel cap on the tank.??


Yes sir, that’s one of the very first things I did.
Update: friends diesel mechanic brother in-law was nice enough to look over engine. Determined that one. That injector pump requires oil and it was really low. Two: One of the injectors is either dirty or defective. He recommended trying Kleen cetane boost injector cleaner before replacing injector. Mixed 16 oz of that with 5 gallons of fuel (enough for 50 gallons) and bush hogged for 40 minutes without any issues....so far. If there was going to be positive results with the injector cleaner I didn’t expect it so soon so I’m skeptical. Will test more tomorrow.


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## thepumpguysc (Jan 25, 2015)

Be careful w/ mixing that stuff so strong..
I've seen it eat fuel systems apart from the inside..
Dilute it asap after u find/solve the problem.


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## pkty (Jun 28, 2019)

I will do that. Hope it continues runs good without all that juice Thanks thepumpguysc for all the advice you give to everyone! 


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