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Diesel injection pump: replacement and selection

When and why it is necessary to replace diesel injection pump

On the average, the diesel injection pump serves for 200,000 – 300,000 kilometers of mileage. The component requires replacement if the pump barrel/plunger assemblies, control rack teeth or delivery valves are worn out. Also the pump can break down because of control rack jamming, disconnection from the pressure regulator, plunger levers clamps loosening.

Signs of fuel injection pump replacement necessity are traces of fuel leakage from the pump, loss of mounting position of the timing belt or chain, excessive fuel consumption, troubled engine start, its unstable and too noisy operation, loss of power.

The fuel injection pump is replaced in service station conditions only. Ingress of even smallest dirt particles in the fuel line during installation is strictly unacceptable, as it can break down not only the component, but the engine as well. Moreover, the fuel supply system should be adjusted after installation of a new part. For this, each injector is adjusted separately with the help of a special tester.

How to select injection pump

The most fuel injection pumps are used in fuel supply systems of diesel engines, but also injection pumps can be found in the direct injection system of gasoline engines. In the latter, pressure is lower than that in components of diesel engines.

By construction, the fuel pumps are divided into: in-line fuel injection pumps, distributor fuel injection pumps, and Common Rail fuel injection pumps. In the in-line pump, supply of fuel into the cylinder is performed with the help of special pump barrel/plunger assemblies; their quantity is equal to that of cylinders. In such pumps an amount of injected fuel and moment of its supply is regulated mechanically or by the electronic system. The in-line pumps are reliable: they are lubricated with motor oil and are undemanding to fuel quality.

The distributor injection pump contains one or two plungers for all engine cylinders. Such a pump is more compact and has smaller weight, moreover, it performs more uniform fuel supply. The disadvantage of the component is quite short lifetime of adjacent parts. The distributor pumps differ by types of the plunger driving mechanism. There are pumps where plungers are driven by an axial cam plate, and those driven by inner or outer cam actuators. The first two types of the component are notable for a longer lifetime: they do not presuppose pressure of fuel applied to the drive shaft elements.

The Common Rail fuel injection pump is used in the common rail direct injection system. The component can have 1-3 plungers, actuation of which is performed with the help of the camshaft or cam plate. This system is the most advanced and used in latest generations of engines.

Efficient and reliable fuel injection pumps can be found in the assortment of such firms as: Bosch, Delphi, Febi Bilstein as well as other proven manufacturers.

Buy only those components, which are designed for your car. Take into account that the pumps differ one from another, in particular, by size, thread parameters of the fuel supply pipe, diameter of the mounting seat and other characteristics directly affecting operation of the engine.