Modern vehicles have made massive advances over their counterparts of older years, especially in areas such as economy, performance and exhaust emissions. Much of these advances are down to the application of technology and in particular, electronics. However, this can cause problems as vehicles become older and run for higher mileages.
EGR stands for Exhaust Gas Recirculation. This is a process that involves a small proportion of the exhaust gas from an engine being returned to the combustion chambers and is designed to reduce the amount of nitrous oxides present in car exhausts. Nitrous oxides are produced when combustion occurs at high temperatures, and the EGR process reduces cylinder temperatures, thus reducing emissions of nitrous oxides. Devised and implemented on a number of cars before the wide-scale introduction of catalytic converters, EGR systems are a common fitment on both diesel and petrol-engine cars and light commercials.
However, set up to run at their best efficiency, the vast majority of engines exhibit little difference with or without EGR fitted. Further, without EGR most vehicles run better, produce more power and consume less fuel. This is especially the case now, as modern fuels contain far fewer additives and contaminants than was the case when EGR was first introduced. Research suggests that fuel consumption can be increased by as much as 5% when EGR is used. So why do it? The answer is mostly down to the need for manufacturers to produce vehicles for a wide variety of countries, where standards of fuel can be very varied. As production and supply will be diverted to different countries based on demand and sales, the use of EGR enables manufacturers to meet emissions standards without the need to tailor electronic systems to specific markets.
In the long term, EGR systems can suffer reliability issues, especially on older vehicles or ones that have travelled high mileages. The system is an integral part of a vehicle exhaust and physically situated close to the engine. It is therefore subject to extreme temperature variation, which can lead to physical failure over time. The system can also become clogged with exhaust deposits, and this is particularly an issue for diesel vehicles, where systems can become useless even with relatively low mileages. Once problems occur, replacement is often considered the only solution, but can be extremely costly. Failed or damaged EGR systems must be attended to; however, as they can cause significant loss of performance and increased fuel consumption, and can also lead to serious engine damage.
EGR Removal is the obvious solution and is a relatively simple and straightforward job. However, simply removing the relevant parts is definitely not enough. In virtually all modern vehicles fitted with such systems, EGR removal must be accompanied by completely reprogramming the vehicles’ electronic engine management systems. Done correctly, this process will enhance fuel economy and performance and a vehicle’s emissions will be close to, if not equal to the original standard.
If your engine management light comes on, or there is an indication that the EGR system is faulty, then EGR removal may well be the best and most cost-effective option. Whatever the solution, any such problem really must be attended to as a matter of urgency, or serious and expensive engine damage can result.