2001-2004 GM 6.6L LB7 DURAMAX
The LB7 Duramax Motor was first introduced in 2001 and continued through mid-2004. To easily identify the 01-04 LB7 motor the eighth digit in the vin number will be a “1” which is the engine code. This motor is designed with a high pressure fueling system that uses a common rail injection backed with a single CP3 pump that can exceed pressures of 27,000psi of fuel rail pressure. Being different from the newer models, the LB7 is equipped with a fixed vein turbo instead of a variable vein turbo (VGT), which means is does not come factory with an exhaust break and is not programmable. Typically the emission standards on these early Duramax trucks were pretty basic. The LB7 trucks did not come factory with a catalytic converter or an EGR system unless it was a California emission vehicle.
Some of the common issues with the LB7 pertains to the fuel systems. The LB7 has a slightly weaker CP3 pump compared to the newer models which means they tend to have a higher failure rate. The most common issue or problem is actually the injectors, they tend to fail sooner than newer model Duramax injectors. The failures point to early design of the injector which it has been upgraded over the years with aftermarket injectors which will help the longevity. Also there are always fuel filtration reasons, these common rail injectors need proper filtration! The factory fuel filter filters down through an 8-10 micron filter but the injector needs about 2 microns of filtration. These main, and most common LB7 issues can be fixed with simply installing an aftermarket Fass or AirDog Filtered lift pump system.