I posted this in the previous EGR Blanking thread but putting it here also as it answers a few questions, I've updated it a little
I'm posting a couple of articles explaining EGR's, how they work and purpose etc .
Understanding EGR Systems
EGR Systems: Operation and Diagnosis
The biggest problem with blanking the EGR specifically on the I-CTDI, is that fueling is specifically tailored dependent on temperatures, air pressures and flows, the ECU takes into account these and releases a specific amount of fuel to maintain temperatures within the block and ensure optimal performance, via the MAF and MAP sensor, which both contain temperature sensors, together with other adjustments to the IMRC valve to alter the swirl ratio. This would all need to be taken into account when re-writing or erasing any maps, together with addressing any emissions control maps that may put the car into limp mode as the OBD II Emission standards have been breached.
As the EGR introduces exhaust gases to reduce the overall combustion temperature, then it would follow that with the EGR disabled the overall combustion temperatures would increase and in the article posted above it mentions a couple 100 degrees, which could have a cyclic effect causing the engine to overheat. The block is aluminum and has been designed to work in a certain temperature range, given the use of the EGR, I'm also not sure what effect this will have on the valve and seats as they will also be exposed to far higher temperatures than designed to operate in, not to mention the effect on the exhaust manifold, dependent on which version you have. Of course with the increased temperature the cooling system has to cope harder, which again will affect overall fueling.
I personally think it is too tightly designed into the whole running of the engine to be removed without serious issues, plus is it worth it, there are a few DIY's showing you how easy it is to clean it.
There are also plenty of threads showing how one slight thing such as fuel filter, IMRC solenoid vac leaks etc can have such a dramatic effect on the car.
On the other hand I have full faith in Elite to be able to do the maps and clearly it seems to be working well on the Civic and this would be the only way of possibly achieving it rather than sticking a piece of blanking material in the port, which incidentally would also need to be able to withstand the increased temperatures being subjected to it in exhaust gas. however it is still early days, I would be interested to know how the car fairs after say a year or so.
Clearly I am focusing on the negative points here, but it is the negative points that generally upset us when they happen, all I am really trying to say is, is it really worth all the risks, just to avoid cleaning it? (anxiously awaits response :unsure: )