cummings engine 6B

[buddie]

I have a Samsung excavator with a Cummings 6B engine. Engine bought new with not that many hours. It runs very good for 4-5 minutes, then gradually shuts down as if running out of fuel. I bleed all lines at injectors and it will run again for the same time, then I have to bleed again. It will idle indefinitely, but stops when under load at 2300 rpms. Can anyone help?

Regards,
Ron

 

[Super S]

You may try running with the fuel cap off or loose. I had a case dozer once that had the same symptoms and tried everything but found out the vent in the fuel cap was plugged creating a vacuum in the tank and starving the motor for fuel. Not sure if it will help but worth a shot. Those motors also have a screen in the primary pump where the fuel comes in that may have trash in it.

 

[Delmer]

Which 6B, what kind of injection pump? Mostly out of curiosity, because it's probably blocked somewhere before the engine, so it doesn't matter until you verify that you have pressure (or not) at the pump as it dies.

 

[DJK]

Check banjo fitting on hose in to lift pump there's a screen in there.

 

[td25c]

Sounds like some kind of restriction on the suction line . After checking filter I generally start at the drop tube at the fuel tank & work back to the fuel pump looking for a bad spot or kink in the fuel line ect . This spray rig has the cummins 6bt engine and a slight kink in the fuel hose was all it took to lodge some silicone (probably from when they replaced the fuel sending unit ) in it shutting the engine down . www.heavyequipmentforums.com/showthread.php?13239-Wrecker-call/page3post#44

 

[buddie]

Actually I bought a 10 ft. fuel line and bypassed the fuel tank, ran the line straight to the lift pump and I still get engine shutdown after 7-8 minutes. The engine will idle for long periods. Has anyone had trouble with the lift pump? Does it usually have to be replaced? Thanks for all your replies.

 

[DJK]

Yeah they fail like anything else over time, did u check screen in banjo fitting at inlet to lift pump? Try dumping a bucket of cold water on injection pump when it starts to run bad. If if improves your injection pump is no good

 

[thepumpguysc]

Kinda depends on which pump you have.. if its an inline pump, the overflow valves go bad.. its the banjo bolt on the back side of the injection pump right behind #1-2 injection line..
It has a ball and spring in it and the spring will break.. just remove it and give it a good shake.. or push a small screwdriver in the hole and feel for pressure of the spring.. I don't recommend taking it apart on account there are small shims that can be "misplaced".. if its broken.. replace w/ 2 417 413 084.. Robert Bosch P#, superior diesel in N. Charleston has them..

Reguarless of which pump you have.. the lift pumps are notoriously bad.. you'll need the engine serial # to get the correct 1.. you can call Cummins in Summerville direct..

 

[buddie]

Thanks very much for the info. I took the fuel pump off and let a mechanic look at it. He advised there was nothing wrong with the pump. I decided to replace it anyhow since I had it off. Got it at Cummings in Savannah since I live close. $110.00 solved the problem. Runs good as always. The pump runs off the engine cam.

 

[buddie]

Kinda depends on which pump you have.. if its an inline pump, the overflow valves go bad.. its the banjo bolt on the back side of the injection pump right behind #1-2 injection line..
It has a ball and spring in it and the spring will break.. just remove it and give it a good shake.. or push a small screwdriver in the hole and feel for pressure of the spring.. I don't recommend taking it apart on account there are small shims that can be "misplaced".. if its broken.. replace w/ 2 417 413 084.. Robert Bosch P#, superior diesel in N. Charleston has them..

Reguarless of which pump you have.. the lift pumps are notoriously bad.. you'll need the engine serial # to get the correct 1.. you can call Cummins in Summerville direct..

The pump runs off the cam in engine. I replace the pump for $110.00 from Cummings in Savannah. Solved my problems. Thanks very much for your reply. I'm glad you advised that they were a problem. Must be true as they had half a dozen in stock.