Thoughts on EGR valve blanking.

[SaabC5]

What are the fellow forum members thoughts on blocking off the EGR valve on a 2.2HDi? I've lashed out £4 on a blanking plate but i'm in two minds whether to fit it or not. Having looked down the tube that goes to the EGR valve its constantly getting gummed up with carbon deposits anyway so i can't see what difference fitting the blanking plate will make. Others have suggested faster spool up times of the turbo and also cleaner oil but what are the downsides. If the EGR valve wasn't needed why would Citroen (and all other manufacturers for that matter) install them?

[steelcityuk]

Ooh this is a bag of worms...

They fit them because it lowers Nitrogen Oxide content in the exhaust gas.

I blank them off on the old XUDs but the HDi could be a different kettle of fish, on my C5 the EGR appeared to have a connection to the cooling system which I assumed helps speed up the warm up process at idle and low engine loads when the EGR is likely to be active. It maybe better to look towards using a EGR cleaner as part of your service routine.

Have a look at this video for general info - " onclick="window.open(this.href);return false;

Steve.

[The Birdman]

Mines off on a 1.6hdi , just unplugged it so it stays closed and got the fault light mapped out .

[cachaciero]

Think that EGR valves reasons / effects etc. was covered quite comprehensively in the following thread. http://www.frenchcarforum.co.uk/forum/v ... =3&t=34544" onclick="window.open(this.href);return false;.

Mine is currently blanked off with a bit of aluminium liberated from a Coke, can seems to make little or no difference to performance or fuel consumption, it may in theory reduce the amount of crud build up in the inlet tracts but I would have to start of with clean inlet tracts to determine this. The water jacket around the EGR pipe is to reduce the gas temperature prior to injection into the manifold.

cachaciero

[haydent]

i tried a soft drink can, and it helped my problem (rpm fluctuation at ~2.2k) but it did not last only about 1 week before burnt through, will replace with something heavier, took about a week also for the error to come on.

[bamba]

Egr valves only function when under low engine loads , they allow exhaust gasses to pass back from the exhuast back into the inlet , effectively dilluting the air intake. If functioning normal under full load acceleration the egr should be closed , so there should be no performance gain by blanking egr off. Removing a egr offten losses a little mpg ,because it open a low engine load , it helps reduce pumping losses caused by the the cylinders pulling a vaccum. If your egr and intake is becoming clogged with crap , then there is a problem causing this .

[haydent]

that is all understood, my reason that its a short fix for the fluctuations till the valve can be cleaned or replaced, though im considering disabling it in the ecu to save crud being pumped back through the engine...

[Monkeyfeet]

Oh yes, big bag of worms all right. Now quick, before the righteous brigade see the thread.
Nice and clean and full working when they should, they're definitely considered to Be A Good Thing.
Clogged up they're a bit of a pain. Only from personal experience here - but on the higher mileage cars I've blanked off it's stopped engines smoking, flatspots and hesitancy. Not noticed any difference in overall mpg. Low revs, less vac sounds plausible to me, but maybe any loss is offset by smother running elsewhere?
I've de-egr'd in software in some cars and simply blanked off in others. Combining the two's best as it stops any engine management lights and stops leakage through poorly closed valves.
TBH though for £3.99 for an eBay plate it's usually worth a go.

[rory_perrett]

Big can of worms. First (engage righteous mode) if a car was fitted with an EGR valve as standard then it is illegal and an MOT failure to blank it off.
(Righteous mode disengaged) But there is currently no test for it so it would only be a visual inspection by the tester who may or may not spot a blanking plate.

I believe that the little local difficulty that VW are currently experiencing is that the ECU would activate the EGR valve operation when it decided the car was under test conditions at times when it would be closed for normal driving/operation.

As said the EGR valve opens to reduce combustion temperature in the cylinder and prevent the formation of NOx which is considered bad for health and the environment. Unfortunately an open EGR valve creates more soot particulates in diesel engines, also considered bad for health, which is why we now have DPF systems on diesel cars.

Under conditions when the EGR valve is closed there will be no difference in performance. While a reduction in pumping losses can improve the mpg on throttled engine (petrol) EGR on non throttle engines (diesel) tends to increase fuel consumption.

[haydent]

the other thing on my c5 II it looks like a b*tch of a job ta get access too so im in no hurry, and can put up with the light for now... when i had the pipe right off for inspection to see if clean the built up crud i could see in the intake was worrying, im sure the valve is similar, huge clumps of tar/carbon, lovely stuff to put back into your engine....

[Stickyfinger]

Should the EGR valve not be thought of as a "long term service item" in the same way a 100k oil change on an Auto box, water pumps, DPF, long belts and such ?

Do we expect a little to much these days ? We used to accept a 30k Valve regrind as the norm.

[haydent]

sure , its no surprise its clogged up