The EGR valve's purpose is to open and close (normally electronically) at certain moments during different the rev ranges, but these valves get clogged up with carbon deposits, which can make them fail, or even get blocked making them stuck altogether either open or closed.
Symptoms can vary from poor idling speed, knocking, loss of power, engine unresponsive, smoke from the exhaust pipe, and the engine management light coming on. If not dealt with, this can lead to turbo damage, a very expensive part when compared to the cost of an Egr replacement.
Different symptons can be poor idling speed, thumping, misfortune of force, engine lethargic/unresponsive, smoke from the exhaust system, and the yellow engine management light coming on. If this is not dealt with it can lead to other issues which can cause damage to expensive parts on the car i.e. leading to turbo failure.
The EGR valve helps your vehicle all the more effectively and completely burning your fuel by recirculating an allotment of your fumes discharges and running it through the burning process once more. This effects in a more finish burn of the fuel which diminishes you car’s toxic emmissions
In the our current modern day vehicle engines recirculate some of their exhaust fumes back into the cars engine with the aim of decreasing emissions. This is the the main benefit of the EGR system being on a vehicle. The negative side to this is that exhaust gasses containing carbon deposits are always being recirculated through the cars engine through time creating a build-up of carbon deposits in areas such as the intake manifold etc which will lead to issues later on.
These carbon build up sometimes contribute to the failure of the EGR valve itself. Replacing an EGR valve can sometimes be costly and in the case of high mileage engines the continual carbon build up can eventually lead to complete turbo failure or even engine failure.
Removal of the EGR valve and or system can be by simply blanking off the exhaust input and the reprogramming of the ECU results in lowered engine temperatures, improving fuel economy, the cars throttle response and it can also can lengthen engine life by reducing oil contamination and carbon deposits.
Yes it is legal to remove the EGR system and it doesn’t currently form part of the MOT test. Whether this might be tightened up in the future, no one knows and our best guess that even if it is, then it will not be applied retrospectively.