Cummins problems

[flighteagle]

I have a 300 Cummins that has been running fine. Now it idles rough then quits, when I add throttle it hesitates then quits or will run ok. It isn't showing any codes and I am hesitant on taking it out into traffic. I never leave the fuel tank low, always keep,it full and always add "Diesel Clean". Open to ideas?

[Old-Biscuit]

When was last time you changed fuel filter?

[WorldCat25]

Originally Posted by Old-Biscuit

When was last time you changed fuel filter?

Agree with the fuel filters. [Mod Edit]

[Vickie 4369]

Originally Posted by flighteagle

I have a 300 Cummins that has been running fine. Now it idles rough then quits, when I add throttle it hesitates then quits or will run ok. It isn't showing any codes and I am hesitant on taking it out into traffic. I never leave the fuel tank low, always keep,it full and always add "Diesel Clean". Open to ideas?

Fuel pump better known in the diesel industry as Lift pump, I had the same problem with mine while in Hershy a few years ago got stuck right in front of the gate of Hershy park PA, I had to use the toad to push it to get it off the road and to a place where we could work on it.

I went crazy looking for it, had to call cummins with the engine number to find out where it was hidden.

They mount them behind the ECM on the engine just behind the timing cover.

When I called the local cummins dealer they had 50 fuel pumps in stock so that indicated to me they are a common failure item.

I was also told they had been superceded to a better design for durability.

Ted.

[imnprsd]

Maybe your 3-lift pump bolts are lose and you are sucking air into your fuel delivery system?

This is easy to check once you gain access to the top of your engine. And it happens a lot to engines with more than 50,000 miles. Consequently, tightening lift pump bolts should be on everyone's preventive maintenance list.

I spent 2 seasons and almost got stuck 3 times because my lift pump bolts were loose.

After you check that you can look at this option to protect your CAPS injection pump.

http://www.irv2.com/forums/f123/cumm...mp-458337.html

Note: The "pink" line in the diagram is more applicable to Monaco and/or Spartan Chassis type FASS installations.

[SeattlePirat]

Originally Posted by flighteagle

I have a 300 Cummins that has been running fine. Now it idles rough then quits, when I add throttle it hesitates then quits or will run ok. It isn't showing any codes and I am hesitant on taking it out into traffic. I never leave the fuel tank low, always keep,it full and always add "Diesel Clean". Open to ideas?

IT would be helpful to know more about how old etc is your motor? ISB?