What exactly does an EGR Valve do?

zootfloot

zootfloot

zootfloot

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My crappy diesel astra has been running really badly of late, anyways i changed the MAF sensor thing, and also changed a collapsed pipe and it is running slightly better, but not as it should.

After reading around it seems that this EGR valve could be the cause of the problem, it may just need a good clean, but a replacement is probably likely.

I am going to grab a copy of the haynes manual and have a pop at sorting this issue out but it got me thinking...as i know nothing about engines/cars in general, what do all these parts that i replace do exactly.

I found out what the MAF sensor does, hell it even seems logical but the EGR valve remains a mystery, there seem to be varying explanations.

It just may be that my googling skills are rubbish.:(
 
Exhaust Gas Recirculation, its to reduce emissions and to burn off and reuse some of the combustion gasses, the EGR valve gets clogged with oil and can cause problems.
 
basically recycles your exhaust gases back through your engine to keep emissions down... however if you look at the components inside after a good few years of having the EGR connected, you will see just how much crap builds up. Its been known on few engines as a silent engine killer.

ta-da

InletValvewithEGRcrap.jpg
 
So i am definately moving in the right direction looking at the EGR valve with regards to how sluggish the car is and there is some black smoke when accelerating hard?
 
Its a Y Reg astra 1.7 DTi estate....its my work car, so im mostly concerned with the reliability and economy (Which so far have both been excellent)
 
What are the consequences of removing the EGR and running without it for a prolonged period on a fairly modern diesel engine (Focus 05 2.0 TDCI)?
 
Depends on when in the engines cycle the EGR system is actually used, mines had two MOT's since being removed and it passed the emissions test with flying colours.

I've also removed the SAI system which reduces emissions on startup but makes the car sound like a cross between a tank and vacuum cleaner.
 
EGR is purely to reduce peak combustion temperatures by introducing an inert gas (compared to oxygen anyway). This has the effect of reducing the combustion rate.

The reduce in peak temperature massively reduces NOx formation. NOx isn't measured on an MOT so you will not fail it by removing the MOT.

Blocking it off helps keep the engine cleaner, as well as improving MPG. Win-win.
 
Completely removed my EGR System this weekend just gone.

Cut the flange off the EGR valve, and welded it up with some plate steel. Then bolted it back on.

Inlet side? Made a new flange, drilled and tapped it to fit my boost gauge nipple :)
 
TaKeN said:
Completely removed my EGR System this weekend just gone.

Cut the flange off the EGR valve, and welded it up with some plate steel. Then bolted it back on.

Inlet side? Made a new flange, drilled and tapped it to fit my boost gauge nipple :)
Click to expand...

Hi I guess you have a HDI from your image? Have you done any other mods? I have got a mr whippy remap to 120-130 bhp and it's a lot better! I was thinking of unplugging the egr valve but was unsure! Has it made a diffrence?
 
phi1 said:
Hi I guess you have a HDI from your image? Have you done any other mods? I have got a mr whippy remap to 120-130 bhp and it's a lot better! I was thinking of unplugging the egr valve but was unsure! Has it made a diffrence?
Click to expand...

Yep HDi 90, 3 Door :) Manstone blue. Full GTi-6 interior & steering wheel. 283mm GTi-6 brake setup.

Intercooled and whippy mapped > Click here for my intercooler build thread

Its been RR'd at Powerstation putting out 131.5 BHP with 200.5 ft/lb

Just need to get the 150bhp map sorted now :) , Unplugging my EGR didn't seem to make a noticeable difference. Although having it uplugged is much better than having it plugged in!!!!! The gunk it puts into the intake is unreal
 
TaKeN said:
Yep HDi 90, 3 Door :) Manstone blue. Full GTi-6 interior & steering wheel. 283mm GTi-6 brake setup.

Intercooled and whippy mapped > Click here for my intercooler build thread

Its been RR'd at Powerstation putting out 131.5 BHP with 200.5 ft/lb

Just need to get the 150bhp map sorted now :) , Unplugging my EGR didn't seem to make a noticeable difference. Although having it uplugged is much better than having it plugged in!!!!! The gunk it puts into the intake is unreal
Click to expand...

I was going to put an intercooler on mine but there is no off the shelf product and I am hopefully going to get something a bit quicker in a year or so! I have a 3 door HDI Dturbo. I think I am going to unplug mine at the weekend.
 
fonzee said:
basically recycles your exhaust gases back through your engine to keep emissions down... however if you look at the components inside after a good few years of having the EGR connected, you will see just how much crap builds up. Its been known on few engines as a silent engine killer.

ta-da

http://img.photobucket.com/albums/v727/ross2482/206%20HDi%20Cylinder%20Head%20Madness/InletValvewithEGRcrap.jpg[ IMG][/QUOTE]

I'll see your valve, and raise you an inlet ...

[IMG]http://img5.imageshack.us/img5/8061/pugengine005.jpg
pugengine006.jpg


And an inlet from an older engine without an EGR system.

pugengine012.jpg


:eek::eek:
Click to expand...
 
It took me 2 cans of carb cleaner and a good hour or so with a toothbrush to clean out my inlet manifold and EGR...it was probably worse than that actually!
 
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