February 2022

fuel pumps used primarily for the passenger car segment in the late 1990s have gone through several incarnations to become the HP5 versions used today. Although, throughout the generations, the function of the fuel injector has not changed, the complexity of the fuel delivery process has developed significantly. As worldwide emissions standards became increasingly stringent, purely mechanical injectors gave way to solenoid controlled electromagnetic versions, working with sophisticated electronics to improve their performance and therefore reduce emissions. This has led to Piezo injectors entering the fray. These contain piezo crystals, and can carry out more injections per cylinder stroke then a solenoid activated version, under higher fuel pressure, which improves combustion efficiency still further. “The final element is the electronic management of the injection process. Based around a closed-loop control system, DENSO’s Intelligent–Accuracy Refinement Technology (i-ART) is a self-learning injector fitted with its own microprocessor. This makes it possible to continuously monitor and adapt fuel injection per combustion in each of the cylinders and means that it also self-compensates over its service life.” Fatiha added: “One of the major implications for the European independent aftermarket is that, although repair tools and techniques are under development for the DENSO authorised repair network, at present there is not a practical repair option for fourth generation fuel pumps or injectors. Therefore, although fourth generation CRS service and repair can, and should be, undertaken by the independent sector, fuel pumps or injectors that have failed cannot currently be repaired, so must be replaced with new parts.” Common Rail fuel injector replacement will certainly continue to feature on a garage’s most tackled jobs, simply due to the huge vehicle parc and how hard the component performs. Julian Goulding, Marketing Manager, Eire & Nordics, Delphi Technologies Aftermarket, commented: “Reasons for failure include particle or water contamination, a build-up of deposits or incorrect installation. Possible signs that injectors require replacement are an illuminated engine light, rough idle, an engine knock, surge or misfire, fuel leakage, poor fuel economy and increased emissions. “If a garage is to reap the revenue that common rail fuel injector replacement offers, it really needs to be able to pinpoint very quickly and accurately that it is actually the component at fault. Having the right diagnostic kit therefore becomes even more important to a garage, as the first action would be to interrogate the vehicle’s OBD with a quality diagnostic tool, such as our Bluetech VCI item.” He continued: “If the OBD has generated a fuel injection system fault code, then the next step is to check the injector’s functionality. Again, the right tool can be a massive benefit. For example, our Sealed Rail Diagnostic Kit can be connected to the injectors, preventing the need for a complete system removal and refit. The Sealed Rail Diagnostic Kit can help determine if the fuel pump is faulty too. Plugging it directly onto the high-pressure outlet pipe from the pump and then cranking the engine to record pressure in the system sees it display the results digitally. If the figure differs from the specified pressure measurement for the vehicle application, the pump could be faulty. If this is the case then garages can carry out on-vehicle 50 AFTERMARKET FEBRUARY 2022 DIESEL www.aftermarketonline.net testing of the pump’s inlet metering valve (IMV) using Delphi’s False Actuator Kit. This will check if the IMV is at fault.” Julian added: “If the IMV is not operating correctly then it is a straightforward job to replace it and so avoid having to remove and refit the whole pump.” Integral role Moving further up the pipe, NGK recommends glow plug replacement should be part of diesel vehicles’ winter service as they play an integral role in their economy and emissions performance. “Instead of changing one faulty glow plug,” said NGK Marketing Manager Mark Hallam, “workshops should upsell by replacing all of them. If one plug has failed, it is extremely likely that the remaining plugs will shortly suffer a similar fate. By replacing the vehicle set, not only will the tight emissions legislation be complied with, but as the glow plug is now an integral part of the engine management system, the starting and cold drive quality will be kept at its maximum.” On removal and fitting, Mark said: “As glow plugs are often installed in engines for many thousands of miles, some vehicles are more prone than others in presenting removal problems. If there is doubt that a glow plug can be removed without damage, then if accessibility, circumstances, and time permits, then apply penetrating oil around the glow plug, then a squirt of engine oil. The vehicle should then be continued to be used and tackle the job another day - to allow the oil to penetrate and do its work. Remove the glow plug whilst the engine is still hot, using obvious precautions to protect hands. To avoid damage to a new glow plug, follow the installation advice on the NGK packaging. Always install on to the taper seat by hand, do not over tighten the glow plug - or the terminal if the electrical connection is secured via a nut.” Mark added: “NGK’s Spark Plug and Diesel Glow Plug 2021/22 catalogue is available now. It includes full details of the company’s glow plug range including six new glow plugs.” Right: NGK diesel glow plug Below: Diesel Deep Clean from Lucas Oil Products