With up to 300 horsepower, the 6.6-liter Duramax LB7 engine utilized a high-pressure common-rail fuel system, direct injection, and a 23,000 psi Bosch CP3 fuel injection pump. The engine wasn’t free of flaws, however, especially with its fuel system. +Read more
This generation of the Duramax turbo-diesel lacks a fuel lift pump, which causes the Bosch LB7 fuel pump to work overtime to pressurize and draw fuel from the tank. This design results in air in the fuel lines, and in higher power applications, low fuel rail pressure under acceleration.
The LB7 fuel filter housing can also leak at the O-rings. Over time, the O-rings can deteriorate due to age and normal wear. Air in the fuel system, hard starts, and an illuminated check engine light can be symptoms of an O-ring leak.
Shop ProSource Diesel’s selection of fuel system parts, including LB7 fuel lines, pumps, filters, and more.