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Time to clean up – Part 1

By autotech-nath on June 27, 2017

Driven by false emissions claims and the associated impact on pollution, the bell is tolling for diesel engines. ASNU takes a look at what this means for garages. As ever, with change comes an opportunity for the brave to corner a growth market in GDI diagnostics and repair. Will you be primed and ready for this type of repair work?

The demise of the diesel engine is perceived to be imminent. Major towns and cities will soon see restrictions for entry by diesel-engine vehicles and this will have a major effect on the future car parc and the vehicle service and repair market. Should workshops continue to invest in the expensive equipment required to test and service diesel vehicles, knowing that their market will dwindle as the cost of the repair becomes more expensive? At what point will owners begin to question whether the cost of the repair is more than the vehicle is worth?
Garage service and repair workshops are at a crossroads. Where to deploy capital expenditure? The growing market for petrol and alternative fuels would seem a logical answer. ASNU delivers three articles focusing on the options for garages around Gasoline Direct Injection (GDI) engine service and repair.
The first article here looks at how GDI came about and asks what the decline of diesel engines might mean for diesel specialist repairers. The second article in the July issue will investigate injector fault diagnosis and replacement options. Finally, in the September issue, we’ll tackle the technology around GDI and injector diagnostics, understanding flow rates and spray patterns. Then we’ll turn theory into practice, featuring a case study on an independent garage who has already taken the GDI plunge. Has the investment been worth it so far?
The diesel service market can be divided into different sectors. The professionals’ core business is testing, servicing and repairing diesel injectors and fuel pumps. Conversely, the perceived amateurs’ core business is general vehicle repairs and servicing, with diesel injectors akin to a side-line of the main business.
The professionals are the recognised groups of Bosch and Delphi Diesel Workshops. The equipment used for testing, servicing and repairing diesel injectors and fuel pumps within these groups is equivalent to many hundreds of thousands of pounds of capital expenditure. Major investment in equipment, staff and training, stock of service and repair items, a clean room and premises to house their diesel service programme, can cost anything up to £35,000.
For the amateur, buying a test bench could cost anywhere between £13,000 and £26,000 and the equipment is possibly only geared to test one injector at a time. This is on a small scale by comparison, delivering a time-consuming service, taking longer and, in many cases, with the injectors not being repaired in the same manner as the well-structured and equipment-rich professional groups.
As the diesel arena declines, the professionals are destined by commercial nature not to let their market dominance be diluted by small scale operations. Many will find additional services to offer, some may reduce their staff, but they will try to maintain their business against all odds.
First notice will be struck with a price war. What the professional knows is that the amateur checking one injector at a time will take  far longer to service a set of diesel injectors than themselves. By reducing the price of a service or an exchange set of injectors, they know this will push the amateur to the limit of what is cost effective, working all day to do a set of injectors at a cost, with a profit that will only just cover the cost of the lease/loan

repayments on the equipment the amateur is using. The second notice will come from the shortage in supply of specific parts required to service the diesel injectors.
Whilst the market is buoyant there are several parts suppliers, but as the market shrinks, the manufacturers will not be so keen to produce parts in bulk, in fear that they will be left on the shelf. Production will reduce and costs will increase.
The time is now to prepare for a sea of change in servicing and repair, as developments in Gasoline Direct Injection (GDI) engines make petrol once more the chosen fuel. GDI is here to stay and, with vehicle manufacturers prioritising its development, the outlook is set to fair for at least the next two decades. GDI injectors will fail and these vehicles will require professionally trained engineers with the right equipment to
carry out diagnosis and repair.
ASNU: Experts in injector diagnostics 
There’s not much we haven’t seen in our 27 years as market leaders in gasoline injector diagnostic testing and servicing. The ASNU network services over 600,000 gasoline injectors per year worldwide, with distribution in over 60 countries. Our injector diagnostics programme covers all gasoline injectors used on cars, bikes and marine engines. As you can imagine, we have an extensive knowledge base that we gladly share with service workshops using our kit via education and support materials and advice, which you too could benefit from.
With both the workshop and the VM warranty department equipped with the ASNU system and support, the ability for the workshop and the warranty department to both quickly and simply identify, confirm or eliminate injector related problems has improved immensely.
Since the creation of the gasoline combustion engine, the fundamentals haven’t changed. With a GDI engine, combustion still requires three essential elements: Air, Fuel and Ignition. The quantity, timing and delivery of these three elements has been refined and now, through research and development, are delivered in a more efficient manner and at unimaginable speeds to original conception.
There are many different manufacturer-led names for GDI; Spark Ignited Direct Injection (SIDI), Smart Charge Injection (SCI), High Precision Injection (HPI), variants of ‘petrol direct injection’ and Fuel Stratified Injection (FSI), to name a few. They all have the same feature; direct injection for a gasoline engine. The advantages offered for the motorist and the VMs mean there will never be a return to the original manifold/port injection systems.
GDI as we know it now, has been in mass production since 1997, when Mitsubishi introduced Carisma, using Hitachi-produced GDI injectors. The initial launch was one of expectation; all the other VMs waited to gauge acceptance for this type of engine. Even though most of them had already been working on such systems, the motorists’ reaction to the GDI vehicle was the question that hung in the air.
It was answered swiftly; GDI proved to be a winner. As a family saloon, Carisma appealed perfectly to a mass market desiring both performance and economy. The die was cast. Exposure was good to start with and any initial problems with the system were credited to teething problems caused by the fuel quality in the UK leaving deposits in the combustion chamber. This wasn’t necessarily the case, but it wasn’t known at the time.
Fast forward to modern day. The GDI System has two running modes:
This mode is the economical combustion cycle. In some systems, the Air to Fuel ratio can be as high as 65 to 1. In this mode, the injector delivers a minimum amount of fuel in to the combustion chamber, just before the piston reaches TDC and before ignition. This mode is used at idle and light throttle settings when the vehicle is driven slowly.
This mode is what would be called a normal combustion cycle, with an Air to Fuel ratio of 25 to 1. In this mode, the injector delivers a normal amount of fuel into the combustion chamber. This gives the engine the required performance as the vehicle accelerates.
The Engine Management System determines when the system needs to switch between the Stratified Charge Mode and the Homogeneous Running Mode.
On a GDI system, the fuel is injected directly into the combustion chamber at a much higher pressure than manifold systems, up to 200 bar. These systems now require fuel pumps and injectors made of stainless steel and must be capable of performing at a much higher specification than ones seen on previous manifold injection systems. It delivers very precise quantities of fuel at extremely high pressures and in short periods of time, in some cases, for fractions of a millisecond.
To control these systems, the ECU is also of a higher specification and required to supply a higher current of up to 90V on some systems. There are many manufacturers of this type of system, but Bosch are recognised as one of the leaders in the development of GDI Technology.
Phone: 0208 4204 494
COMING UP: In the July issue of Autotechnician, ASNU investigates common GDI injector problems and how they can be safely diagnosed and fixed.


About Autotechnician
Autotechnician is a magazine published nine times a year, delivering essential information to independent garage owners and technicians in the UK. Delivered both digitally and in print, autotechnician provides readers with technical, training, business advice, product and news, allowing our readers to keep up to date with information they need to run and work within a modern workshop.
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