GM/Detroit 6.5L – Fuel System – OVERVIEW

The fuel control system delivers fuel from the fuel tank to the injectors via a series of pumps, filters, passageways, and ports. Accumulators and regulators help maintain pressure throughout the system for optimum fuel delivery and performance.
The 6.5L EFI delivers fuel using the same basic components as the non-electronic version. System components include (figure 4-1):
โ€ข Fuel Tank Assembly
โ€ข Lift Pump Assembly
โ€ข Fuel Filter Assembly
โ€ข Fuel Injection Pump Assembly
โ€ข Fuel Injection Lines
โ€ข Fuel Injection Nozzles
โ€ข Fuel Return System

The PCM-controlled injection pump is mounted on top of the engine, under the intake manifold. The pump is driven by the camshaft through two gears (refer to figure 2-2). One attaches to the front of the camshaft, the other attaches to the end of the pump shaft. Because these gears are the same size and have the same number of teeth, the injection pump shaft turns at the same speed as the camshaft.