Although the injection pump has capabilities to pull fuel from the tank, an engine mounted fuel pump is included in this system as an additional assist in the event of air in the lines such as running out of fuel, fuel line air leaks or air from occasional fuel tank service. (Figure 4-7).
The fuel pump’s main job is to supply 51/2 lbs. to 6 Vi lbs. of pressure through the fuel filter to the Injection pump.
Fuel is drawn from the fuel tank through the tank filter by the fuel pump. The fuel pump is driven by an eccentric on the crankshaft. The injection pump drive system uses the end of the camshaft where the fuel pump eccentric is usually located in a gasoline engine. See figure 4-8. The diesel fuel pump is located on the right side of the engine between the fuel tank and fuel filter. The design of this pump is quite similar to the gasoline engine pump: however, the two components are not interchangeable.
All 1982 and later models will be equipped with GM SPEC. 6031 hoses which are made of “Viton” and contain a non-permeable tube inside.
The hoses will include a yellow stripe and the words “ Fluro Elastomer” on the outside. Their purpose is to reduce emissions when hydro-carbons pass through the hose material.
