EGR system

dirtysac

Active Member
Mar 2, 2008
250
0
Yorkshire
is there an electrical connection on the 1.9 pd engine?

No.

Just a re-circ pipe, you block

Two other pipes I forget what they are exactly one is to prevent shudder and the other is something else.

Anyway you just can block these with crimps, tape or whatever. You actually leave them open if you wish it makes no difference.
 

jonjay

50 Years of 911
Jun 27, 2005
5,843
1
Essex
I run an allard EGR replacement I get shudder on turn off (almost un-noticabe though) and the emission light comes on sometimes. When measured at MOT my emission have actually gone down.

I had a performance gain of 5BHp according to dyno. Plus I gained on average 2mpg on a long run. My EGR valve was a mess almost half the diameter was clogged full of crap.
Shame you cant get them no more :(
 

ChrisGTL

'Awesome' LCR225
Nov 17, 2007
2,459
2
Huddersfield

Bogwoppit

Full Member
Aug 30, 2005
1,085
0
Lincs
I have a worry about disabling the EGR system. A lot of Renault dci engines are suffering turbo failures which is being put down to the EGR valve sticking shut, this is causing the turbo to get to hot and failing. I assume the Renualt turbo relies on the EGR to help shift the exhaust gasses? There is alot about this on parkers and honestjohn.
As I have blanked my EGR and disconnected the vacuum hose on my pd 150 is this something we have to worry about on the VAG engines?

"What follows applies to Renault 1.5DCI engines, but may explain why the diesel turbochargers fail: The EGR valve should open to allow carbon dioxide (which acts as a cooling gas) into the combustion chambers when the engine is under load (>30% boost). This allows the combustion chamber temperature to drop and thus the temperature of the exhaust gases. If it sticks in the closed position the exhaust gas temperature will rise causing a) the turbo bearings to fail and b) engine oil into the induction system. This can cause the engine to run on its crankcase oil until it is either stalled or goes bang. Problems with EGR valves are often the cause of rough running when the valve is stuck in the open position as well. In several cases turbos have blown but the EGR valve has not been replaced. Inevitably the new turbo unit will not last long. "
 
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Robb1990

Active Member
May 14, 2008
299
0
But Renault are ****. Surly if hotter intake goes in, the burn temp must go up? Both the PD and non-PD diesels had EGT sensors dont they?
 

Robb1990

Active Member
May 14, 2008
299
0
:happy: My tutors son at college has one, 03 plate, 80K had knackered bushes on the rear beam, and the cables on the window regs have rusted. :rolleyes:
 
Dec 5, 2007
888
0
N W Leeds
But those running a map will have hotter combustion chambers anyway since the map allows greater fueling/boost pressure and better combustion. I don't think there is a higher incidence of turbo failure in mapped cars for the average owner? This does not apply to looners and people who hoof it 110% all the time.
I suspect the turbo failure is caused by the general crudding up and **** that that the EGR and CCV system cause to the engine. Burning engine oil, IMHO aint good for an engine and contaminants etc will find their way back into the oil system.
What would you rather have - 100% fresh air going into your lungs and stale C02 air coming out each breath, or some of that same stale air going back in to your lungs again?
 

Muttley

Catch that diesel!
Mar 17, 2006
4,987
31
North Kent
The purpose of EGR is to reduce peak combustion temperatures, which it does by injecting inert gas into the inlet charge, reducing the amount of oxygen present. Exhaust gas counts as inert becuase all the oxygen should be used up. Of course it's hot and full of soot, but it is inert!

The Environmental reason for EGR and peak combustion temperature reduction is the reduction of NOx emissions. NOx - oxides of nitrogen - are formed by the nitrogen in air in the inlet charge being burned, oxidised by the high temperatures that can be reached in a modern engine. Peak comustion temperatures occur at peak load situations and are transient - accelerating away from traffic lights, opening up at mid-speeds and the like. EGR controls these transients by reducing the oxygen content, resulting in unburned fuel coming out as soot. Way to go for the environment, guys.

Now, if Renaults are failing becase their EGR is sticking shut, I would guess that they are boosted more than the VAG engines and make much more use of EGR to control combustion temperature.
 

brad1

Guest
i am not that confident at doing this myself, but does anyone near me fancy helping me remove my egr and cleaning it, or help me fit a allards race pipe?
crate of beer or cash?
 

Robb1990

Active Member
May 14, 2008
299
0
honestly mate, its easy, a little awkward, but easy. 2 bolts into the intake chamber at the top can easily be accessed with an extension bar and 5MM HEX, then 2 bolts under the unit holding the pipe to the exhaust manifold, these are the awkward ones, need just the HEX attachment on the ratchet and position it just inbetween the brake servo (black thing behind the brake fluid res) and some pipes. then the unit will swing around for the last bolt to be undone. VAC pipes off, and the unit is free. The hardest part is getting the vac pipe off the anti shudder valve, i ended up breaking the nipple in it.
 
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