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[Webby the Bear]

Hi guys,

I haven't posted for a while but I have been on the net and the Tube looking in to the performance of the EGR.

So am I right in thinking that it takes around 15% of the exhaust gases from the cyclinders and chucks them back in? If it's only 15% why bother? I wouldn't have thought that would be of any benefit to the emissions being such a low amount? 

Is there a Check Engine code if something goes wrong with it?

I presume the main problem you'd get would be flow and clogged up tubes/pipes?

If so can I follow this guide for my 2.5V6....
http://www.omegaowners.com/forum/index.php?topic=90553.0

Cheers guys and here's hoping for a good EGR chat 

Ps, got my brake piston turner inner tool. Looks fine apart from it's c;learly ben used before  but fek it.... if it gets the piston back in nice and easy then I couldn't give a monkey's chuff

[Andy B]

.....
Ps, got my brake piston turner inner tool. Looks fine apart from it's c;learly ben used before  but fek it.... if it gets the piston back in nice and easy then I couldn't give a monkey's chuff

A G clamp or large screwdriver will push your brake caliper cylinders back in. 

[Webby the Bear]

Cheers Andy, bought it now anyway.... i now got all tools to do the brakes. including a quality set of irwin vise grips from b&q 

[Kevin Wood]

So am I right in thinking that it takes around 15% of the exhaust gases from the cyclinders and chucks them back in? If it's only 15% why bother? I wouldn't have thought that would be of any benefit to the emissions being such a low amount? 

It's not so much the effect it has on the exhaust gases, which is minimal, but the effect it has on combustion in the cylinders as it enters the intake. It effectively fills some of the cylinder capacity with an inert gas that won't react with the fuel, so the burn is slower and cooler, and there's a reduction in some harmful emissions and pumping losses as a result. It operates only at part load.

Is there a Check Engine code if something goes wrong with it?

On an Omega, only if the valve doesn't follow its' commanded position (i.e. it gets stuck).

The ECU isn't clever enough to tell if the exhaust gas is actually passing through it.

I presume the main problem you'd get would be flow and clogged up tubes/pipes?

No. They stay clear, except for a thin layer of soot. Jamming of the valve is probably the most likely cause of trouble.

[Webby the Bear]

So am I right in thinking that it takes around 15% of the exhaust gases from the cyclinders and chucks them back in? If it's only 15% why bother? I wouldn't have thought that would be of any benefit to the emissions being such a low amount? 

It's not so much the effect it has on the exhaust gases, which is minimal, but the effect it has on combustion in the cylinders as it enters the intake. It effectively fills some of the cylinder capacity with an inert gas that won't react with the fuel, so the burn is slower and cooler, and there's a reduction in some harmful emissions and pumping losses as a result. It operates only at part load.

Is there a Check Engine code if something goes wrong with it?

On an Omega, only if the valve doesn't follow its' commanded position (i.e. it gets stuck).

The ECU isn't clever enough to tell if the exhaust gas is actually passing through it.

I presume the main problem you'd get would be flow and clogged up tubes/pipes?

No. They stay clear, except for a thin layer of soot. Jamming of the valve is probably the most likely cause of trouble.

Thanks Kevin. So just reading through the guide I take it that would sort a jamming valve?

It is interesting to know about the gases being inert as they re-enter the intake. So presumably if they burn slower the main impact would be better fuel efficency??

Is the EGR something you can ''disconnect'' and the car will still run ok? I'd presume so just thinking about it but obviously I'm not sure about that 

[Kevin Wood]

EGR does give marginally better fuel economy, but probably barely noticeable. If the valve is electrically disconnected the engine will run with a fault code. You can also blank off the path of the gases and leave the valve on and it'll run normally.

[Webby the Bear]

Cheers mate.
So the main thing is the constant reduction in harmful gases then?!

So in this pic of my EGR....

... Is the cyclindrical object the valve housing? And presumably if I get a fault code with the valve that's jamming then do I open this up and manually unstick it or just follow the guide?

cheers kev 

[2woody]

15% is way OTT, more like 5%, certainly on a petrol

[maracus]

When I blanked off the EGR on my td mig I actually improved my mpg by >1 mpg, not a lot but a very definitive +1 across the board in terms of different driving styles/durations/distances/time of year etc, so I was under the impression that the EGR is of F.A. use for improving mpg but solely for reducing "N0X" emissions... Whatever the hell that is; but..

I have just blanked off the EGR on my astra 1.3 cdti as it was giving me jip, 'cos I couldn't be arsed to remove and clean it properly, and my mileage/gallon fell like a rock in the sky from mid fiftys to mid forties. I'm not sure if it's something else that coincidently started playing up at the exact same time because I've had a couple of niggles trying to rear their ugly head so it might be down to something else, bit one things for sure; I think I'd have huge benefit from getting the EGR back in play after a proper good session with the mrs' toothbrush!