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Cat 257B 2 down on power

Seanndiane

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Apr 2, 2014
Messages
13
Location
Greenville, SC
I have a 1900 hr 257b that I just bought. Near the end of the first tank of fuel, it went down on power(like I let off the throttle) it would surge like it was starving for fuel. When I took the cap off, it was "suctioned" to the tank. I refueled and it worked normal for quarter of a tank then went down again for maybe 45 seconds then ran normal. Since then, it has happened several times after about 1 to 2 hours of constant use. Today (at about just below 1/4 tank) had the same issue till I filled with fuel.

Is it possible the fuel cap "vent" is not letting air in and vapor lock is forming? It seems that it only happens at low fuel or sustained run times, but is cured after the fuel cap is removed
Is there a fuel pickup "tube" that can be blocked in the tank?
 

Nige

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G..G..G..Granville.........!! Fetch your cloth.
Could be the cap is bad, but you may have sucked up some crap into the filter, or have a filter that needs changing. Have you checked the water separator and drained if necessary..? When was the last time the fuel filters were changed..? This should be a regular maintenance practice.

The fact that when you went down to 1/4 tank the 2nd time and had the same issue again suggests that the check valve in the fuel tank cap is not working properly.
 

Seanndiane

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Apr 2, 2014
Messages
13
Location
Greenville, SC
Could be the cap is bad, but you may have sucked up some crap into the filter, or have a filter that needs changing. Have you checked the water separator and drained if necessary..? When was the last time the fuel filters were changed..? This should be a regular maintenance practice.

The fact that when you went down to 1/4 tank the 2nd time and had the same issue again suggests that the check valve in the fuel tank cap is not working properly.


The filter was changed by the dealer when I bought it. I have "looked at the separator" (the clear bowl right?) but have not emptied it since it happened on 1st, 2nd and 3rd tank of fuel since it was changed and it didn't appear to have any water in it.

I' m suspecting the cap too, mainly due to the suction the first time, and the re-occurrence after continuous use. Hopefully, someone with previous "faulty cap" issues will chime in before I spend $$. The 1/4 tank thing may be poor indication and operating on a slope. This mornings occur acne was after only 10 minutes, but was at 1/4 tank, That's why I asked above a fuel pickup tube (airplanes and race cars use them due to bank angles and sloshing).
Thanks for your help
 

Mobiltech

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Was there suction on the tank when it happened this time?
These machines also have an electric fuel pump that fails quite regular. Can you hear the pump running when you turn the key to the start position with the armrest down.
 

Seanndiane

Member
Joined
Apr 2, 2014
Messages
13
Location
Greenville, SC
Was there suction on the tank when it happened this time?
These machines also have an electric fuel pump that fails quite regular. Can you hear the pump running when you turn the key to the start position with the armrest down.

Except for suction the first time, haven't really noticed any. Will listen for fuel pump tomorrow.Do the pumps go out gradually or just quit for good? I.e. Work intermittently? Or would it run for awhile without the pump working, and just bog down when you burn some fuel off and get on a slope?

If it acts up, can I shut it down but leave it in run and listen for the pump? Or will that "reset it" where I won't be able to listen for it? Thanks
 

Mobiltech

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It will run without the electric lift pump working but it will have low power. As the tank gets lower it will get so that it only idles and it will cough and sputter if you try to revv it up.
The pumps can fail slowly.
There is a changeup pump that is supposed to last longer.
 

Seanndiane

Member
Joined
Apr 2, 2014
Messages
13
Location
Greenville, SC
I listened for the pump and couldn't hear anything obvious (although it's hard to hear with the stupid beeper going.. I still don't know what purpose the beeper serves since I sat in seat, lowered arm, fastened seatbelt and beeper still goes....maybe a battery run-down protection)

Anyway, best I can tell, no pump running (2007 257B series 2) if it is the pump how $$$$bad is it?
 

truecountry

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Sep 24, 2007
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Location
clarksville va
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ok fast fix to see if it vapor locking on fuel cap drill a 1/8 hole in fuel cap but make sure you have if off and nothing falls in tank ...next if that's doesn't fix it pull pickup tube outta tank its clogged and cant get enuff fuel
 

Mobiltech

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The pump is mounted on the filter . You can take the line off that comes out of the filter to the fuel injection pump and put it in a bottle or jug . If you can then get someone to start it or reach in yourself and pull the armrest down and turn the key to start. It wont crank but the pump should run for about 10 seconds after you let go of the key.
The pump is about 300 bucks . Its a little more for the better one

It depends on your serial number whether you have the new pump already or not

Description of Change: New pump groups are now being used on the machines that are listed above. These new pump groups will enhance the reliability of these machines.

Adaptable To: The 349-5327 Fuel Priming Pump and Primary Filter Gp will replace the 258-3442 Fuel Priming Pump and Primary Filter Gp. The 349-5328 Fuel Priming Pump and Primary Filter Gp will replace the 305-6411 Fuel Priming Pump and Primary Filter Gp. The 361-3869 Fuel Priming Pump and Primary Filter Gp will replace the 232-5877 Fuel Priming Pump and Primary Filter Gp .

Effectivity
Model Adaptable to Machines Effective with Machines
259B3 S/N:YYZ1-416 S/N:YYZ417-UP
279C S/N:MBT1-1925 S/N:MBT1926-UP
289C S/N:JMP1-1738 S/N:JMP1739-UP
299C S/N:JSP1-1375 S/N:JSP1376-UP
257B3 S/N:B7H1-554 S/N:B7H555-UP
267B S/N:CYC1-1482 S/N:CYC1483-UP
 
Last edited:

Seanndiane

Member
Joined
Apr 2, 2014
Messages
13
Location
Greenville, SC
I disassembled the fuel cap and cleaned the foam filter....It seems to be getting worse. It's doing it now at 1/2 tank when on an incline. It did it today and I opened the cap. It did not help the problem. It was still down on power and didn't get better after a few minutes. I refueled it and it got better within minutes. I think the cap is ok.i will try the pickup tube if I can figure out where it is.
ok fast fix to see if it vapor locking on fuel cap drill a 1/8 hole in fuel cap but make sure you have if off and nothing falls in tank ...next if that's doesn't fix it pull pickup tube outta tank its clogged and cant get enuff fuel
 

Seanndiane

Member
Joined
Apr 2, 2014
Messages
13
Location
Greenville, SC
I called cat today and they said $98 for a "transfer pump" I asked if that was the only one they had and they said "no, they have a priming pump also" I didn't get the price since they mentioned the transfer pump first. I asked if the priming pump was primarily for starting or running and the "parts guy" said it's mainly for starting. I will try your test of the "one on the filter". I was hoping the $98 pump was the one I needed, but sounds like it might not be.
The pump is mounted on the filter . You can take the line off that comes out of the filter to the fuel injection pump and put it in a bottle or jug . If you can then get someone to start it or reach in yourself and pull the armrest down and turn the key to start. It wont crank but the pump should run for about 10 seconds after you let go of the key.
The pump is about 300 bucks . Its a little more for the better one

It depends on your serial number whether you have the new pump already or not

Description of Change: New pump groups are now being used on the machines that are listed above. These new pump groups will enhance the reliability of these machines.

Adaptable To: The 349-5327 Fuel Priming Pump and Primary Filter Gp will replace the 258-3442 Fuel Priming Pump and Primary Filter Gp. The 349-5328 Fuel Priming Pump and Primary Filter Gp will replace the 305-6411 Fuel Priming Pump and Primary Filter Gp. The 361-3869 Fuel Priming Pump and Primary Filter Gp will replace the 232-5877 Fuel Priming Pump and Primary Filter Gp .

Effectivity
Model Adaptable to Machines Effective with Machines
259B3 S/N:YYZ1-416 S/N:YYZ417-UP
279C S/N:MBT1-1925 S/N:MBT1926-UP
289C S/N:JMP1-1738 S/N:JMP1739-UP
299C S/N:JSP1-1375 S/N:JSP1376-UP
257B3 S/N:B7H1-554 S/N:B7H555-UP
267B S/N:CYC1-1482 S/N:CYC1483-UP
 

Seanndiane

Member
Joined
Apr 2, 2014
Messages
13
Location
Greenville, SC
image.jpg I don't have a pump on top of my filter except "hand priming button.
I have 3 fuel lines that go through the lower bulkhead: 1 goes to the injector rail (I assume return to tank) 1 goes to small filter before 3 inch pump mounted on side of engine (I assume it's called transfer pump, from this pump, fuel goes to the large filter in the picture, then to the fuel injector "manifold?") and 1 goes towards the cab (can't locate where it goes without raising the cab)
I will pull the hose off the injectors this morning and test, then tilt the cab and check out the other lines. I guess I will have to tilt the can anyway if that small pump needs to be replaced.
 

Mobiltech

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Okay. I guess I should have gotten your serial number. I thought you had the newer style with an electric transfer pump. The mechanical pump was more reliable but can still give problems. Make sure you have good flow from the tank to the transfer pump. The pump on the engine should have a lever you can pump by hand. If you take the outlet line off that pump you should be able to see it pumping fuel when you stroke the lever.
What is your serial number so I can give you more info.
 

Seanndiane

Member
Joined
Apr 2, 2014
Messages
13
Location
Greenville, SC
After THOROUGHLY cleaning the engine compartment, I can get a better view. After putting a light close to the small fuel filter and shaking it, I can see some garbage that has settled in the bottom. I will change it shortly and run the machine for awhile and see if that could be the issue (or a contributing factor). Still leaning towards the fuel pump, but start cheaper and work your way up I guess.
 

Nige

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Messages
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Location
G..G..G..Granville.........!! Fetch your cloth.
You can remove and wash the bowl under the filter. It gets used again so long as it is not damaged. You ought to replace the seal that goes between the bowl and the filter, should be a couple of $ - no more. If you have not replaced the filter recently I suggest that you do that at the same time. I would (in no particular order): -

Clean fuel line from tank to filter/priming pump.
Prove that hand priming pump is pulling fuel from tank without too much effort (do this with filter removed).
Replace filter, clean bowl, replace using new seal.
Prove fuel lines from filter to transfer pump are good by removing the incoming line at the pump and use the priming pump to flush the system.
Prove the transfer pump by removing the fuel delivery line from it to the engine and manually operate the transfer pump.

Here is a diagram of what your fuel lines look like. You can clearly see the priming pump/filter assembly and the transfer pump. I note you are missing the external drain hose from the tap on the bottom of the bowl to the ground. This is item 30 in the illustration, listed as 33cm of 8C-6959 Hose - price about $4.

257 Fuel System.PNG

This is what your priming pump/fiter breaks down to. Item 1 is listed as a 156-1200 Element. Check the Part Number installed on your machine to make sure it's the same. If it is then all the following numbers are good. The bowl at the bottom is a 112-9401, you should not need to replace it unless the old one is cracked or damaged. The kit of seals for the filter, bowl, & drain tap is a 128-8614, you WILL need this kit to install the new filter. The seal kit is listed at $3.17, the filter itself at $18.46. Prices at your Cat dealer may vary a bit from these numbers but not by that much.

257 Fuel Filter.PNG
 

Seanndiane

Member
Joined
Apr 2, 2014
Messages
13
Location
Greenville, SC
Thanks for the diagram..it really helps.I am using the machine daily (building my own house) and cat dealer is 1 hour round trip away, so I can't spend a whole day repairing, so I will have to take it in steps. I removed the fuel line, cleaned lines and changed the small filter.it was loaded with silt. I have switched to ultra low diesel so I can see through the filter better. After changing the filter, I primed it and another small load of silt filled the filter. I ran the machine for about 2 hours (7/8 tank down to 3/4 without issues)I will know better when it gets lower on fuel. The large filter was changed about 2 tanks of fuel ago (12 hours?)don't know if the dealer cleaned the bowl. I will remove and clean it next time I have a bog down or I have some free time.I wonder if there is a lot of crap in the tank that could be drained when I get down below 1/4. Is there a drain valve? Is it covered by a removable panel on bottom?
You can remove and wash the bowl under the filter. It gets used again so long as it is not damaged. You ought to replace the seal that goes between the bowl and the filter, should be a couple of $ - no more. If you have not replaced the filter recently I suggest that you do that at the same time. I would (in no particular order): -

Clean fuel line from tank to filter/priming pump.
Prove that hand priming pump is pulling fuel from tank without too much effort (do this with filter removed).
Replace filter, clean bowl, replace using new seal.
Prove fuel lines from filter to transfer pump are good by removing the incoming line at the pump and use the priming pump to flush the system.
Prove the transfer pump by removing the fuel delivery line from it to the engine and manually operate the transfer pump.

Here is a diagram of what your fuel lines look like. You can clearly see the priming pump/filter assembly and the transfer pump. I note you are missing the external drain hose from the tap on the bottom of the bowl to the ground. This is item 30 in the illustration, listed as 33cm of 8C-6959 Hose - price about $4.

View attachment 118339

This is what your priming pump/fiter breaks down to. Item 1 is listed as a 156-1200 Element. Check the Part Number installed on your machine to make sure it's the same. If it is then all the following numbers are good. The bowl at the bottom is a 112-9401, you should not need to replace it unless the old one is cracked or damaged. The kit of seals for the filter, bowl, & drain tap is a 128-8614, you WILL need this kit to install the new filter. The seal kit is listed at $3.17, the filter itself at $18.46. Prices at your Cat dealer may vary a bit from these numbers but not by that much.

View attachment 118340
 
Last edited:

Nige

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Jun 22, 2011
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G..G..G..Granville.........!! Fetch your cloth.
Appreciate your position needing the machine and the distance to the dealer.
If the dealer changed the large filter 12 operating hours or so ago then the bowl had to be removed and installed on the new filter. The filter should still be good.
If silt is accumulating in the bowl then try draining it daily and see what you get out of it.
I don't think there is any sort of inspection cover to allow the tank to be drained and cleaned. I will check though and get back to you.
 
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