Cummins ISL, Runs For 30 Sec Then Stalls

[jleamont]

Anyone ever replaced their fuel lines from the tank to the engine? Mine have fuel drops on them in the basement and the engine appears to be stalling due to air in the fuel. After 30 seconds the fuel filters go 3/4 empty, engine stalls, I thought it was the transfer pump and i replaced it with the latest updated Cummins pump today, no improvement

Then I noticed the fuel drops when I lowered the ceiling down in the basement. The new pump is nice-- it self primes when you change the fuel filters, after 5 versions I feel like this was a good PM idea anyway. I unhooked the supply line from the tank and put it into a 5 gallon diesel fuel container, still stalls.

Next is to replaced the lines from the front to the back, I am not happy about this but i guess it's my only option now. The Cummins dealer told me this is fairly common that the rubber breaks down.

2002 Monaco/HR anyone had this happen?

[wolfe10]

Yes, fuel hose breakdown is not that unusual. And, since it is on the suction side of the lift pump, you will see little fuel leakage out-- just air IN. The primary fuel filter filled 3/4 with air is a really good indicator of a suction side leak.

But, this sentence would make me want to verify the cause of the problem before undertaking line replacement: "I unhooked the supply line from the tank and put it into a 5 gallon diesel fuel container, still stalls."

[kaypsmith]

I think I would want to put a short supply line from the 5 gallon container directly to the pump to verify that the supply line does need replacing.

[jleamont]

I unhooked the line at the tank and dropped it into a jug of diesel up front to make sure it wasnt the fuel pickup in the tank pulling the air since the fuel tank is 3/4 full.

The little beads of fuel over the on the fuel lines in the basement area actually made me happy I was headed in the right direction.

Thanks for the replys, today will tell, I am going to replace both lines from the front to the back (feed and return).

[jleamont]

I replaced the fuel line from the tank to the fuel separator, and the line from the separator to the fuel pump on the engine, that was a project! After 4 times of filling the filters and it stalling it finally stayed running and I left it run for 45min on high idle (cruise control on). I think I am good now.

FYI anyone with a Cummins engine in this time frame (ISB,ISC, ISL,ISM, ISX same pump) you might want to replace the fuel pump or have it replaced, Cummins told me they had problems with the pumps sucking air due to a design flaw within the pump gasket where the electric part mounts to the housing.

Good preventative maintenance if its a know problem, I just wonder what else should start to think about replacing on the chassis.

Thank you Wolfe10, you are always a help!