Cat 268-B stalling problem

[Mowermoney]

I was wondering if any of you have any experience with a cat 268 -B.

Mine has always had a low power issue. My older machine is a Cat 248 with 74 horsepower. The 268 is listed at 84 horsepower but has never performed as well as the 248. Both are turning the same mulcher, an FAE UML 128, 48" cut.

The stalling problem has gotten progresively worse. The engine slows if the machine is placed under any type strain. Simply raising or lowering the lift arms causes a drastic reduction in Engine rpm. Pushind debris or loading the bucket causes a similar reaction. When using the mulcher, the engine stalls to the point of shuttting down if too much load is applied.

I have changed fuel and air filters hoping that the problem would go away, but nothing has helped. I once took it to the cat dealer and asked them to fix the problem. The charged me $1600 and I still have the same problem.

Any help would be greatly appreciated.

 

[machmeter62]

I was wondering if any of you have any experience with a cat 268 -B.

Mine has always had a low power issue. My older machine is a Cat 248 with 74 horsepower. The 268 is listed at 84 horsepower but has never performed as well as the 248. Both are turning the same mulcher, an FAE UML 128, 48" cut.

The stalling problem has gotten progresively worse. The engine slows if the machine is placed under any type strain. Simply raising or lowering the lift arms causes a drastic reduction in Engine rpm. Pushind debris or loading the bucket causes a similar reaction. When using the mulcher, the engine stalls to the point of shuttting down if too much load is applied.

I have changed fuel and air filters hoping that the problem would go away, but nothing has helped. I once took it to the cat dealer and asked them to fix the problem. The charged me $1600 and I still have the same problem.

Any help would be greatly appreciated.

For that $1600 CAT check-up, was a compression test, injectors checked, and timing verified? How many hours on the engine? With a gradual power loss; it could be the rings and valves too!

 

[machmeter62]

For that $1600 CAT check-up, was a compression test, injectors checked, and timing verified? How many hours on the engine? With a gradual power loss; it could be the rings and valves too!

Is there anyway of checking for some type of binding in the mulcher itself, that would rob the performance; I know very little about the machines?

 

[tlbuser]

I'd check fuel pressures first. Especially check flow from the tank to the pump. Then pull the injectors, do a compression test and get the injectors tested/rebuilt (an injector shop would probably be much cheaper than Cat). If the engine checks out, then next would be the hydraulic system. As said previously, remove the mulcher, see if that helps.

 

[Mowermoney]

The engine stalls regardless of the attachment being used. Simply lifting or lowering the loader arms causes a loss of engine rpm. The engine has around 1700 hrs, too few for a major compression loss. Yes, Cat did check out hydraulic pressures and found the high flow to be low(3400psi) @ 28 gpm, They could never get it any higher. The low flow was right on the money.

I could have a fuel pressure problem. To my knowledge, the fuel pressure has never been checked. I did check for a blocked fuel pick-up. No problem there.

Thanks for all the input.

 

[Eagleview]

You more than likely have an air leak in the fuel line . If you have not already got one fit a clear inline fuel filter just before the injector pump . If im correct you will see aeration bubbles in the filter . If this is the case you will need to check all clamps and fittings and even the pickup tube in the tank if need be . This will cause the exact problems you speak of .

 

[plowrup]

Not having the unit to look at, it is tough to diagnose, but I think I'd pull the Injection Pump and have the Governor looked at-

 

[Mowermoney]

Iron Horse, you may be on to something. I noticed fuel on the Injector pump near the fuel supply line. I removed the nut and cleaned the washers with starting fluid and moved them around, tightened the nut back up and tried it out. It seems to be better. I couldn't make it stall completely as before. It still has a slight drop in rpm when I close the clamps on my grapple at idle, but not as much as before. I think I have two problems working here. I'm going to have my mechanic check the pressures. He's a former CAT service tech. He's pretty good on most problems.

 

[Eagleview]

It may take 30mins or so to get all the air to be forced through the injectors as air being air will get trapped in all the high places . Expect it to drop RPM's at idle while operating any hydraulics as it is quite a parrasitic drag and your engine makes very little HP at idle . Ive fixed two of my machines in the way i described . My tractor was doing as you say and i found a tiny scratch on a hose barb that was letting in air and my Cummins powered truck had a simillar complaint when a throttle shaft seal got a little hard and would let air in . I found that by putting the pickup and return hoses in a clear container of Diesel and watching it at idle . The return line was blowing bubbles when it should have been expelling solid fuel .