t550 stalling out

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twentythreemx

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Apr 21, 2023
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Hey guys, t550 I bought with around 2000 hrs, I put 400 on it without issue.

It started cutting out on me, its a very sudden loss of power and sometimes it will recover but most of the time it shuts off. It got worse as some time went on. It got to the point of it happening every 10 min or less. Thats when I parked it. I honestly can't tell if it sounds like its losing fuel or like if its electrical or something... I couldn't figure out any type of pattern (hot/cold, low/high rpm, flat/angle, high/low fuel, etc), figured it was time for some service.. Air filter was pretty bad. Replaced the fuel filter as well. After starting it, it died out almost immediately again within a few minutes. However after that it ran great for about 20 min before I shut it off. Next day I ran it for about 2 hours and it didn't do it once, I thought I was in the clear!!! However it's now back to doing what it was doing before....

Any suggestions on where to start? I threw in some diesel fuel additive/cleaner with it as well when I did the fuel filter change.
 
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twentythreemx

twentythreemx

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Apr 21, 2023
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i noticed today that when its running the primer bulb is completely flattened like squeezed in... is this normal? or is that some type of potential hint at my issue (plugged line somewhere, or maybe in the filter housing o r something?)

any advice?
 

foton

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I would look at the fuel cap, sounds like the vent is plugged and creating a vacuum in the fuel line. to test try running with it loose and see if the primer bulb stays roundish.
 

laurencen

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Oct 3, 2016
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this is not normal, you have a blockage of fuel to the bulb, first try running with cap loose if still collapsed start tracing fuel lines to it, could be a kinked fuel line or the fuel pickup in the tank blocked, years ago I had a tractor, jacked it up to fix a tire ended up squashing the steel fuel line with the same result you have
 
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twentythreemx

twentythreemx

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thanks. kind of what i was thinking, but didnt think about the first easy one (fuel cap). will start there and move onto my lines

do you know on a t550 if ill have to remove the fuel tank to get the pickup out? or is it accessible after lifting the cab?
 

laurencen

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sorry do not own one, Bobcat has a great parts section on line it will give you a pictorial location relative to the tank and fuel line routings
 
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twentythreemx

twentythreemx

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pulled the fuel cap and the bulb still squeezes in, not as quickly but definitely still does it. so I dont think its the cap.

i found the return (thought it was the pickup) and popped it out... unfortunately that obviously isn't part of the equation.

found a parts diagram and the pickup is more in the middle of the tank. I cannot even SEE it on the machine, much less actually attempt to remove it.

I cant imagine you have to pull the engine or hydraulics to get to it, that would be crazy right? Maybe i need a brighter flashlight lol..

EIther way, I'm pretty stuck if i can't find that thing.

hate to do it but going to make another thread specifically asking about the fuel pickup location, I don't feel like it should be that hard to find... cant find anything for my model specifically referencing where its at.
 

laurencen

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pull the line off the bulb and try compressed ait, not high pressure but see if it can clear it
 

foton

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loosen the fuel cap and try to use only around 5 psi of air chances are you will blow the filter screen off but the machine will work again.
 
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twentythreemx

twentythreemx

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loosen the fuel cap and try to use only around 5 psi of air chances are you will blow the filter screen off but the machine will work again.

tempting but at $100 a piece for fuel filters, I like the idea of the screen lol.

has anyone left the sreen off and put in an in line filter thats cheap/easy to change?
 
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twentythreemx

twentythreemx

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ok so update.. I'm leaning less toward a clogged pickup now.

After letting the machine sit over night, I ran it again this morning, not moving the machine I idled it up/down several times, the primer bulb never deflated...and squeezing it i can feel fuel moving through it.

so that tells me i'm NOT sucking air in anywhere, as that would be a consistent issue, it also confirms my pickup isnt plugged, or that would be consistently causing the deflated bulb as well.

However I then hopped in and moved it 50 feet, and sure enough the bulb was deflated.

so, IMO that tells me i got a floater in the tank and the suction draws it to the pickup and it gets stuck, agree?

I shut the machine off, watch the bulb re-inflate to normal (can confirm I can squeeze it and feel it pulling fuel).. start it up and it sits there fine. this time i barley moved it at all, maybe 15 feet, slow and flat... checked it, it was fine.. then moved it again a little more aggressively (to stir up the tank more) and it deflated again.

so i think i need to quit chasing down the pickup, and try to chase down how to clean out this tank. anyone agree/disagree or have a better plan of attack?
 

foton

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maybe too confirm your feelings you could hook up a drill powered pump to the suction side of the tank and pump the fuel into a white bucket, let it sit awhile and see if you got trash ,and you could watch the volume of fuel being removed , if you have good flow then it drops off then you will know something is blocking it off. If that happens put a weight of some sort on the drill pumps suction side and put it in the fuel fill neck and drain the tank as much as possible, maybe you will be able to get out enough to make a difference without pulling the tank. good luck
 

laurencen

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not buying the floater, had similar on the toolcat in winter but it was fuel gelling, your machine needs a certain amount of fuel to idle, quite a bit more to work my guess is there is a blockage thats allowing enough fuel to idle but thats it,

pull the line into the fuel filter and bypass filter just to try, when was the filter replaced? do you have a water trap on that machine
 

Tango-Charlie

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Feb 8, 2016
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I support your theory. I had an IH 656 tractor that was doing the same thing. After several frustrating hours of troubleshooting I found that there was a piece of rust in the tank that would work its way around the tank and block the tank outlet. I had actually back blew some air through the lines and it ran great again until the outlet got blocked again. I had to remove the tank and clean it out and the problem never came back. In my case I could actually see the junk on the bottom of the tank causing the problem before I cleaned it out. Good luck and keep us posted if that is what happened.
 
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twentythreemx

twentythreemx

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not buying the floater, had similar on the toolcat in winter but it was fuel gelling, your machine needs a certain amount of fuel to idle, quite a bit more to work my guess is there is a blockage thats allowing enough fuel to idle but thats it,

pull the line into the fuel filter and bypass filter just to try, when was the filter replaced? do you have a water trap on that machine

when its working, its working fine, at full power. if it was the gelling or a clogged screen I would think it would run rough the entire time. definitely could be wrong, but it makes sense.

sounds like i need to figure out how to get the fuel out of the thing. its 100% full right now, so, thats great...
 
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twentythreemx

twentythreemx

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maybe too confirm your feelings you could hook up a drill powered pump to the suction side of the tank and pump the fuel into a white bucket, let it sit awhile and see if you got trash ,and you could watch the volume of fuel being removed , if you have good flow then it drops off then you will know something is blocking it off. If that happens put a weight of some sort on the drill pumps suction side and put it in the fuel fill neck and drain the tank as much as possible, maybe you will be able to get out enough to make a difference without pulling the tank. good luck

probably a good idea if i can figure out how to make that work, and find something to store 36 gallons of fuel in, lol..

it may never pick up whatever is getting stuck though until the machine actually moves. I guess depends on how much suction the pump puts on the lines... I'm pretty confident the machine will sit there at idle all day and be fine, its only when it moves around that it happens.
 

laurencen

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when its working, its working fine, at full power. if it was the gelling or a clogged screen I would think it would run rough the entire time. definitely could be wrong, but it makes sense.

sounds like i need to figure out how to get the fuel out of the thing. its 100% full right now, so, thats great...
its working fine when it can suck one gallon a hour, may work fine at 3 gallons but when it needs 5 gallons and only get 3 gallons it starts to starve fuel even empty the bulb
 

Markle

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I have a T550 but not your problem. I investigated a bit thinking I may too have this issue one day.
there is a Heavy Equip forum where the poster with a T650 had the identical problem. Allegedly the machine has no screen on the pick up tube from factory. This pickup hole plugs easily. Poster couldn't find/reach the pickup on top of the tank either. ... He ultimately drilled a new hole in the plastic tank where he could reach, and dropped a new line WITH SCREEN in… routed fuel line to bulb… and problem solved. For what it's worth….
 
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twentythreemx

twentythreemx

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Apr 21, 2023
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I have a T550 but not your problem. I investigated a bit thinking I may too have this issue one day.
there is a Heavy Equip forum where the poster with a T650 had the identical problem. Allegedly the machine has no screen on the pick up tube from factory. This pickup hole plugs easily. Poster couldn't find/reach the pickup on top of the tank either. ... He ultimately drilled a new hole in the plastic tank where he could reach, and dropped a new line WITH SCREEN in… routed fuel line to bulb… and problem solved. For what it's worth….
I saw that. Debatable to go that route.

According to the oem disgram my fuel line goes through a fuel exchanger.. not from bulb to tank. Probably a dumb question but I don't even know what that is. Does it just keep fuel cool? I haven't looked for it on the actual machine. Not sure where it's even at. Not sure if something could be plugged there too.

The diagram shows the part number for a line with a screen in it too so idk.

Think I'm going to pull the sending unit and pump out some fuel and get a little camera in there to see what I can figure out.
 

foton

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I do not know if your machine has the fuel cooler, but they do exist on one machine that I know of, A massy ferg 461 tractor , the turbo so sheilded from the fuel tank but they still ran a cooler in front of the radiator to cool the fuel more, In my opinion that design is stupid and just asking for problems.( 2 rubber fuel lines going over the top of the engine too) I guess if you were using the tractor in the artic it would be ok.maybe
 
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