IDENTIFYING PUMPS
While fuel injection specifications can vary widely, even between similar car models from the same manufacturer, the injectors, pumps and ECUS are fitted as matching sets. However, the number of manufacturers Original Equipment fuel injection systems are surprisingly limited.
Carwood here outlines the main pump and injector systems that you are likely to encounter on British roads, along with their common foibles.
Bosch
The Bosch firstgeneration CP1 range includes a compact version (CP1K). The standard version, which is featured being reconditioned, can be identified by the pressure regulator being mounted on the main pump casting and consists of three radiallylocated plungers driven by an eccentric cam. A high-volume, low-pressure in-tank pump supplies fuel to the high-pressure unit, while the fuel pressure is monitored by the fuel pressure regulator (DRV) that is part of the fuel rail, although you might find it located on the pump casing itself (as in our example) and solenoid fuel injectors tend to be fitted. The second-generation CP1H pump was introduced from 2001 and features increased capacity and efficiency; some of these types do not have a lift pump within the tank and utilise a low-pressure gear pump (see CP3). You may also find the fuel metering unit (ZME) mounted to the low-pressure diesel supply line, rather than on the highpressure side of the system, which was inherited from the later CP3. The main issues include leaks and electrical failures.
The third-generation CP3 hails from 2003 and was designed to achieve greater pressures (up to 1800 Bar). Its main foible stems from the rear-mounted low-pressure gear pump breaking its driveshaft, caused by dirt being sucked-in with the diesel from within the fuel tank and snagging the meshing gears (as shown in the photo). Unlike the CP1 pumps, CP3 does not operate at full pressure continually, making it more efficient. CP3 pumps tend to be used in conjunction with piezoelectric fuel injectors, the reconditioning capability of which is limited.
The fourth-generation CP4 arrived in 2007. This is a smaller unit and can generate up to 2000 Bar. Fewer plungers are used, too – CP4.1 has one, CP4.2 has two. To enhance efficiency further, a roller is installed between the drive cam and the plunger, but it is very sensitive to incorrect bleeding operations, which can result in severe damage (as shown on page 8).
Delphi
Delphi’s first-generation commonrail diesel systems started with the DFP1 pumps, which use a similar operating principle to the Bosch CP range (although an in-tank lift pump is used), but the main driveshaft and rotor are combined as a single unit. Typical applications include the third-generation Ford Mondeo (from year 2000), Ford Transit and Jaguar 2.2 diesel (a Ford unit). A mechanical low-pressure pump is also integrated with the high-pressure pump and it wears internally. Watch for fuel leaks, as well as driveshaft and roller wear.
The later DFP3 utilises an eccentric shaft internally and you will find several different versions (3.1, 3.2, 3.3 and 3.4), each of which differs in the number of plungers, drive, pressure output and even size. Roller bearings also replaced plain bearings, which may be one reason why reliability was improved over the DFP1. However, it has been noticed that Delphi pumps appear to suffer more than most from bearing issues, especially if the cambelt has been overtightened. With a 2000 Bar specification, DFP3 pumps may boast a two- or three-plunger design. Some types may be fitted with a low-pressure lift pump. DFP3 pumps are fitted to various Citroën, Dacia, Ford, Hyundai, Mercedes-benz, Peugeot, Renault and Ssangyong models.
The more recent and reliable (to date) DFP6 common-rail pump (as shown in the photo) is fitted with a single plunger, roller and shoe system, with a 2000 Bar capability. It is fitted to various Seat, Skoda and Volkswagen vehicles.
Denso
Although Denso introduced the first commercially available common rail diesel system, the HP0 was used on commercial vehicles from 1995. The subsequent HP2 (from 1998) used a pair of plungers within its compact casing. The HP3 (as shown above) arrived in 2001 and used a different design, incorporating a driveshaft with an eccentric cam. As HP4 pumps (from 2004) tend to be the preserve of commercial vehicles, Denso pumps are mainly fitted to Japanese or Korean vehicles, although they can also be found on certain Vauxhalls and Fords. Carwood reports that they tend to be reliable, with faulty injectors being more common.
Siemens/vdo/continental
Like Denso, Siemens was a pioneer in common-rail technology and was the first to develop high-pressure diesel injection with piezoelectric fuel injectors for production cars. Development was passed to VDO in the early 2000s, prior to the technology being purchased by Continental in 2007.
You will tend to find the matching ECUS, fuel pumps and fuel injector systems on cars produced with engines developed by Peugeot-citroën (PSA) or co-developed by PSA and Ford. These include the DV4TD in the 1.4-litre DV4 engine, the PCR 2.0 DW10TD used in the eight valve 2.0-litre HDI range of engines, the PCR 2.3 DWB10TED for the later 16 valve 2.0-litre HDI, the DV6CTED4 for the 1.6-litre DV6 engine and the PCR 2.3 for the FORD/PSA/JLR Lion V6.
A slight oddity is the PCR 2.3 Puma system for 2.2-litre engines, which does not use piezoelectric injectors. The PCR 2.1 was developed for 1.6-litre applications of the VW Group engine, which also used piezo fuel injectors, as does the PCR 2.3 K9K Euro 5 system employed for the Nissan/renault 1.5-litre unit. Carwood reports that you can find wear in the soft aluminium components within the centrifugal low-pressure fuel supply pump, plus the fuel injectors drift out of tolerance, caused either by failure of the piezo crystals, or the internal electronics. However, the high-pressure circuit tends to be reliable.