Disabling the EGR circuit.

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tamrsoft

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Joined
Sep 2, 2005
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173
Location
Shawford, Hampshire
Car
E220 CDi (2001)
Disabling the EGR.

I have read articles on various forums about disabling the EGR primarily to minimise sooting up of the inlet manifold but I believe it can also give a slight increase to performance. Apart from the risk of increasing emissions in oxides of nitrogen, is there any other negative aspects to doing this due to the higher combustion temperatures at the upper RPMs. Your views please.
 
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You probably can't do it as the MAF will detect the lack of air drawn at idle.
 
I have read articles from those that have done this on the more recent technology diesels that disabling from the vacumn control area of the EGR will cause a fault to be registered in the engine management system. Their methods discussed blanking off the exhaust entry into the EGR but to keep the EGR control (by engine speed I believe) still enabled. Since the MAF only monitors the fresh air into the system I assume it would be unaffected by this modification. I have also read that the EGR is (should be) non-operational at idle and only cuts in at mid-engine speeds (about 1200-2000 rpm). The main failure of this device seems to be gunging up with soot and sticking open causing lumpy and smoky idle as the main symptom. Have you had or know of any experiences using this method. My primary concern is the build up of unecessary deposits in the inlet manifold area.
 
The EGR should be most active at idle due to there being an abundance of air at that point thus more Nox.

I fail to see how blocking the EGR pipe would achieve anything that blocking the vacuum pipe wouldn't. The EGR valve itself isn't monitored, just the amount of air drawn trough the MAF sensor. If the EGR pipe is blocked then more air will be drawn through the MAF which will detect that.
 
EGR (continued)

Most of the articles I have read come from US MB forum members who seem to have played around quite a bit in this area and most of what I quote is from their experience.
I have read that the EGR should be inactive at idle (excellent article at

http://www.fordscorpio.co.uk/egr.htm

on how it should work) although this maybe different for a diesel.
 

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