[007]

EGR is basically for taking care of the emmisions at the idle ( though it helps at other engine speeds also).

In simplest form it takes out some of the exhaust gases & feeds it back to the intake ( Thats why EGR - Exhaust gas Recirculation).

Though it helps to curb the emissions, it do dilutes the charge (hence the power too) & also causes some problems related to the carbon deposits in the intake (near throttle body area)

Most of the engines today have it.

[tsk1979]

Disconnecting the EGR had no effect on anything at all, it was done on a trial basis to see if EGR was faulty. anyways, EGR was replaced with larger dia EGR as part of retro get rid of krrr noise, but thats another story

[SPIKE ARRESTOR]

The basic intention of using an EGR is to reduce the NOx emissions which occur at high engine temperatures. As the exhaust gases are already burnt, they act as an inert gas and reduce the amount of oxygen available at the combustion chamber, the net effect is that it reduces the peak combustion temperatures, thus resulting in lesser amount of NOx production. Generally, the duration for which the EGR opens and closes depends on the water temperature.

Spike

P.S. If the EGR is blocked, you can feel a slight improvement in power.

[ph03n!x]

Originally Posted by tsk1979

Disconnecting the EGR had no effect on anything at all, it was done on a trial basis to see if EGR was faulty. anyways, EGR was replaced with larger dia EGR as part of retro get rid of krrr noise, but thats another story

Guess you are the only one (until now) who has had the EGR at least temporarily removed. I read that there will be an increase in power and fuel economy with EGR reduced (Wiki says fuel economy may increase by as much as 25%). What are your comments on this? Is it advisable to chuck this one out?!

[ronin]

I have had the EGR removed and replaced from my Laura once. I didnt feel any noticeable improvements in power delivery. I had to pay a ton of money for the same too.

[jav]

Had disconnected the egr in my indica a while back, the only difference was a little bit more pull while releasing clutch in first gear without pressing accelerator.

Well as for the mileage part i actually had lower kmpl with egr off, dont know why

now the egr is back on but tweaked slightly to cut off at earlier rpm

[dadu]

Originally Posted by tsk1979

When my safari had that idle surging problem, they disconnected EGR for some time to see if problem goes away. Guess what, no service light

Did they completely remove it, including its vaccum pipes or they unscrewed and left it hanging ??

If left hanging, its working, so no impact on the sensors. If removed completely I am surprised on why no SL.

[satish_tns]

Apart from the power increase, milage increase and specially avoiding the carbon settling on the EGR valve by removing EGR, are we not violating the emission norms by removing EGR? Just had this thought in mind!!

[SPIKE ARRESTOR]

By removing EGR, you are violating emission norms specially NOx which is produced at higher temperature and engine speeds.

Spike

[roy_libran]

My EGR seems to be over-supplying the exhaust gas, and this has been flashed by my Diagnostics computer. I don't wish to outright block the EGR; so what are my other options?

[AMG_ang]

This is possibly because of EGR valve remaining open all the time. Check the electrical connection for actuation of the valve, in worst case replacing the EGR valve should solve your problem.

[apachelongbow]

The concept behind a compression engine is of total loss, the intake of clean air, compressed with diesel fuel, leading to an explosion and the waste gases being scavenged out of the exhaust.
Adding devices like the EGR is a compromise, where in one tries to clean up the tail pipe gases by re-burning the same gas in the combustion chamber. At the best, it will reduce power and decrease mileage, every time fresh diesel combines with exhaust air in the chambers.
Over time the soot/carbon from the exhaust gases will coat the interiors of the cylinders, the EGR valve and lead to a 'sticky' valve condition, with the valve being stuck in either open/closed condition.
If the valve is stuck close, then no issues with the power or mileage, but the ECU understands an error code and throws up amber/yellow light on the dash. If the valve is stuck in the open position, then the car struggles to make any power (dirty gases are going in continuously into the cylinders) and average drops.

The general idea behind the EGR is, to have a cheap way to burn the NO2 gases from the tailpipe, which are a byproduct of diesel combustion.

[pcpranav]

do you need to clean the EGR valve, just as part of long term maintenance ?

does the cleaning job affect the fuel economy, probably increase ?

[a4anurag]

Originally Posted by pcpranav

do you need to clean the EGR valve, just as part of long term maintenance ?

does the cleaning job affect the fuel economy, probably increase ?

Yes it is good to clean the EGR as per manufacturer interval as a choked valve can send faulty information to the ECU and play around effecting the FE.

Worst is there could be emission issue to add the exhaust gases are escaping out fully but gad the EGR be working as it should lesser pollution and slightly more efficiency.

Anurag.

[DerAlte]

Originally Posted by a4anurag

... choked valve can send faulty information to the ECU and play around effecting the FE. ...

In EGR valves that have a position sensor (some old ones don't), the sensor will faithfully send signal that the EGR valve is stuck. That is information about fault, not 'faulty information'! If the valve passageways are choked there is no way to know, other than with a NOx sensor.

Also, EGR doesn't affect FE - it is exclusively for NOx reduction. If EGR is not working, you might get better FE (don't try it though).