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Fuel Line

Common Rail Diesel Opportunities

Sales of diesel pumps and injectors are growing rapidly, but a lot of this business is going through the main dealer and the independent aftermarket is missing out.


There are over 12 million diesel vehicles on UK roads. The vast majority of these will have common rail fuel systems, so there is a huge market for replacement pumps and injectors.

Independent motor factors and garages can take advantage of this growing sector with a new range of Bosch, Delphi, Denso and VDO branded common rail diesel pumps and injectors, as part of an OE-approved remanufacturing programme from Carwood.

The high cost of these components means that they are not typically stocked by factors.

While common rail is no longer a new technology, it is still relatively unfamiliar to the aftermarket, as many technicians and factors have yet to get involved with these systems. This is often down to a lack of understanding, the fear of costly repairs and poor availability. These are all issues which can be addressed through awareness and education.

Remanufacturing & Exchange Programme

Collection of old core is fundamental to the success of the Carwood programme. Therefore the programme operates under an exchange scheme whereby old units are returned for credit every time a new part is ordered. Back-in-box old core management (returning the old part in the replacement part’s box) greatly reduces the risk of returning incorrect products and the risk of damage in transit.

The speedy return of old core is essential to ensuring a high level of product availability, maintaining the cycle of supply and keeping prices as low as possible.

Old core must reach acceptance standards. This means that parts cannot be accepted if they are heavily corroded, dismantled or incomplete, have damage to the housing, seal surface, electrical connections, drive flange or drive shaft. For more information, please see the ‘Core Acceptance Criteria’ section in the main menu.

Quality Assured

Sourcing from an OE-approved remanufacturing scheme means that the remanufactured part is produced in the same manner as the original unit. For example, when you order a Delphi fuel pump or injector, the internal parts within the component have been replaced using genuine Delphi parts. The unit has also been put through the Delphi test process on approved test equipment operated by Delphi trained technicians.

This goes for all remanufactured components, so a Bosch fuel pump or injector will have genuine Bosch internal parts and will have been tested on a Bosch test bench by Bosch trained technicians. Where remanufacture is not possible, new parts are supplied.

Using non-OE standard components could risk garages and their customers thousands of pounds in components and hours of lost time if something goes wrong.

System Overview

The system has two key mechanical/ electro-mechanical moving components: the pump and the injectors. These are the components most susceptible to wear and failure.

Before common rail technology, diesel systems relied on mechanical parts that injected fuel once per cylinder stroke - commonly at around 200 bar of pressure. Fuel injection was controlled by timing the pump to the engine. Although effective, once this system had been fitted and timed, there was very little room for adjustment or alteration without physically altering the timing.

Common rail systems are electronically managed by the engine control unit (ECU). The ECU controls many variables subject to the demand put on the engine by the driver and the conditions in which the engine is operating. Injection can occur up to seven times per cylinder stroke. With faster reacting injectors in development, this figure will soon increase.

The common rail system improves the performance and efficiency of diesel cars at the same time as reducing the emissions created during the combustion process. These benefits mean that common rail technology is here to stay. It is therefore vital that independent motor factors and garages become familiar with this technology sooner rather than later. Those that neglect this market sector will be left playing catch-up.

Increased Fuel Pressure

Another key difference between the old mechanical systems and common rail is that injection pressure is now increased to 200 – 400 bar pressure when idling, and up to 2,400 bar (approx. 35,000 psi) at full pressure (dependent on the system and demand).

In order to generate such high pressures and inject fuel this frequently, highly atomised and accurately, the quality of the system components is critical to the operation of the system. In some cases, internal component tolerances are down to 2 microns (approx. 0.002 mm). This is vital to the life span and safety of the engine: damage caused by poor quality or worn injectors can incur repair bills well over the cost of the original repair and, in the ‘worst case scenario’, may destroy the engine. Manufacturing processes and methods of testing are therefore critical as the components need to be of such high quality.

These high pressures should not be a reason for garages and motor factors to turn away business. Education, training and the experience gained from working with these systems will show that when handled correctly, common rail systems are genuinely safe and a very profitable market sector.


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