The direct-injected LLY Duramax is equipped with a Bosch CP3 injection pump, a high pressure common rail system, and electric fuel injectors, resulting in a maximum injection pressure of 23,000 psi. However, the LLY’s fuel system can have issues later down the road.
Common to Duramax engines, the LLY does not have a factory lift pump. Instead, the injection pump moves and pressurizes fuel from the tank to the injectors, causing more stress on the pump. To extend the injection pump’s longevity, installing an LLY lift pump can help maintain proper fuel rail pressure, especially after modifications. +Read more
Additionally, the fuel pressure relief valve, which uses a small spring to reduce pressure when it gets too high, can fail. The spring can become weaker as it wears, making it so that it cannot retain stock fuel pressures.
Shop ProSource Diesel’s selection of fuel system parts, including LLY Duramax injectors, lift pumps, LLY fuel filters, and more.