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Ask Chris (aka - Moose) Your Own Question
Chris (aka - Moose)
Chris (aka - Moose), Technician
Category: Heavy Equipment
Satisfied Customers: 112
Experience:  16 years of experience
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detroit diesel engine losing its prime

Customer Question

i have a 12.7L 360hp detroit and its losing its prime after running thru the day. i have had it checked out by several different tech. and they cant find the problem.I have had the check valves replaced, the o-rings on the injectors replaced, the #1 injector rebuilt, frieghtliner ran diagnostic test on it for a week and good not find any lines leaking. They also sent it to stewart and stevens for a dyno test that came back good so i am about to go crazy trying to figure out whats wrong. if it doesnt start in the morning all i have to do is take the fuel line off the fuel pump that leads to the front fuel filter and put some fuel in it and spray a little starting fluid and it will start right up.
Submitted: 7 years ago.
Category: Heavy Equipment
Expert:  Bill replied 7 years ago.

Hi Chris,

I had one do me like this about a month ago. It was the fuel pump in my case. I took it off and held it upside down with the weap hole facing up, filled weap hole with solvent and it sucked it right in, it would loose prime intermittently, maybe two times a week just like you describe. The pump was $140 at freightliner.

 

 

Bill

Customer: replied 7 years ago.
hey bill sorry it took so long to respond but it was not the fuel pump it was my #3 injector leaking.
Expert:  Bill replied 7 years ago.

Good Evening Chris,

Very interesting. Were you making oil, fuel in the oil? I presume that the injector was the source of air in the system letting fuel run back to tanks.

 

 

 

Bill

Customer: replied 7 years ago.
HEY BILL, YES THAT IS CORRECT I HAD FUEL IN MY OIL. THOUGHT I HAD PROBLEM CORRECTED BUT KNOW IT IS DOING THE SAME THING AGAIN SO I GUESS ITS BACK TO THE DRAWING BOARD OR SHOULD I SAY BACK TO THE SHOP.