Fuel delivery system
Objectives
-Describe the components of a Fuel delivery system and the purpose of each .
-conduct a visual inspection of a fuel system.
-relieve fuel system pressure.
-inspect and service fuel tanks.
- inspect and service fuel lines and tubing.
-describe the different fuel filter designs and mountings.
-remove and replace fuel filter.
-explain how common electric fuel pump circuits work.
-conduct a pressure and volume output test on a mechanical and electric fuel pump.
-service and test electric fuel pumps.
The Fuel delivery system has the important role of delivering fuel to the injectors. The fuel must also be delivered in the right quantities and at the right pressure. The fuel must also be clean when it is delivered to the engine
A typical Fuel delivery system includes a fuel thank, fuel lines, fuel filters, and a pump. The system works by using a pump to draw fuel from the fuel tank and and passing it through fuel lines and filters to the fuel injection system. The filter removes dirt and other harmful impurities form the fuel. A fuel line pressure regulator maintains a constant high fuel pressure. This pressure generates the spraying force needed to inject the fuel. Excess fuel not required by the engine returns to the fuel tank through a fuel return line.
GENERAL FUEL SYSTEM DIAGNOSIS
One of the key requirements for an efficient running engine is the correct amount of fuel. To accomplish this, fuel must be stored(Figure 27-1). All of this must be accomplished in an efficient and safe manner.
The fuel system should be checked whenever there is evidence of a fuel leak or smell. Leaks are not only costly to the customer but are also very dangerous. The fuel system should also be checked whenever basic tests suggest there is too little or too much fuel being delivered to the cylinders. Lean mixtures are often caused by insufficient amounts of fuel being drawn out of the fuel tank. Lean mixtures can cause bed results in many different diagnostic test, including high HC,O2, NOx readings on an exhaust analyzer and high firing lines on a scope