Just What Good Is The EGR Valve?

[Tasng4]

On the way through France with a trailer I noticed a distinct lack of power as well as a plume of black smoke from the exhaust. Aha! I thought.....blocked/stuck EGR valve. I'll sort it once we arrive at our destination.


I had a look on Fleabay for EGR cleaner and up popped 'blanking valves', i.e. valves that do away with the EGR valve.


My question is what're the advantages (if any) and disadvantages (if any) of getting rid of the valve?


Thanks,


P.S. I cleaned the valve (325,000 kms and never cleaned as far as I know) and now I only have a grey plume of smoke, I assume the exhaust is cleaning itself.

[Andy_with_a_screwdriver]

What an egr does do is cause a load of oily tarry crud to build up in the valve itself and the intake manifold. This is a picture of an egr probably ¾ obstructed, from my Vauxhall after about 14 years and 104k miles.

[Tasng4]

Well mine wasn't that bad, by comparison, just VERY sooty with lumps of carbon.


If the EGR valve collects all this carbon if it's not cleaned then surely if you swap it for one of the blanking 'valves' then this carbon has no where to go and will eventually damage the engine??

[Arctic]

On the way through France with a trailer I noticed a distinct lack of power as well as a plume of black smoke from the exhaust. Aha! I thought.....blocked/stuck EGR valve. I'll sort it once we arrive at our destination.


I had a look on Fleabay for EGR cleaner and up popped 'blanking valves', i.e. valves that do away with the EGR valve.


My question is what're the advantages (if any) and disadvantages (if any) of getting rid of the valve?


Thanks,


P.S. I cleaned the valve (325,000 kms and never cleaned as far as I know) and now I only have a grey plume of smoke, I assume the exhaust is cleaning itself.

Hi Neil.
Have a lovely weekend and numb your brain with all of this below.

https://www.the75andztclub.co.uk/forum/showthread.php?t=12517


Clean your manifold out also and wipe the MAP sensor clean.

https://i.imgur.com/fAZfa4Al.jpg1

https://i.imgur.com/uIjpRK8l.jpg3

https://i.imgur.com/rhXa2uil.jpg4

[alan richard]

If the EGR valve collects all this carbon if it's not cleaned then surely if you swap it for one of the blanking 'valves' then this carbon has no where to go and will eventually damage the engine??

Without an EGR, the carbon will exit with the exhaust gasses. With the EGR it collects around the EGR valve mechanism (or condenses)

It's there to reduce NOx emissions.

(They say: the EGR valve allows a precise quantity of exhaust gas to re-enter the intake the system, effectively changing the chemical makeup of the air entering the engine. With less oxygen, the now diluted mixture burns slower, lowering temperatures in the combustion chamber by almost 150°C, and reducing NOx production for a cleaner, more efficient exhaust. )

I cleaned and blanked mine years ago. Not really noticed any performance difference.

[Tasng4]

Thanks to all who commented, the car continues to run better with a cleaner EGR valve. I will clean it properly when I get home in another 1000 miles.


I tend to side with the designers of the engine, why would it be there if it's not necessary so I don't think I'll bother with a bypass.


Au Revoir.

[Avulon]

Thanks to all who commented, the car continues to run better with a cleaner EGR valve. I will clean it properly when I get home in another 1000 miles.


I tend to side with the designers of the engine, why would it be there if it's not necessary so I don't think I'll bother with a bypass.


Au Revoir.


It's there solely as an attempt at pollution prevention to comply with the most stringent of regulations (misguided or otherwise) for the markets where it would have been sold. Not for engine performance, or even economy. Not because the designers thought it a good idea. - they had no choice.

[Tasng4]

OK, but if it's there purely for emissions/pollution surely if I fit a blanking 'valve' then it won't pass emissions!

[Mike Trident]

Mine has the Egr disconnected, passed its 4th or 5th mot since I disconnected it.

1.31 Is the limit mine measured 0.01.

Very clean running Rover 75

[Tasng4]

Oh! Why O why is there never a straight fwd answer? Mine's a French car and at the last MOT it tested 0.9 and the limit is 1.0 but that may be injectors.


We're in England ATM and I cleaned it here so I'll check after the 1,000 mile drive home.

[Mike Noc]

OK, but if it's there purely for emissions/pollution surely if I fit a blanking 'valve' then it won't pass emissions!


The UK emission test for diesels is a visible smoke test - they currently do not carry out an analysis of the emissions as they do for petrol engines.
The EGR system was added to reduce harmful NOx emissions, but as they currently don't test for those you should be fine, unless of course they spot that you have disabled the EGR.

[BigRuss]

The problem with the EGR is that it sticks if it's not kept clean.

If you test a 100 cars with enabled EGR and rev each to 3000 rpm and let go of the accelerator which will then open the valve, if you look on T4 at the time taken for it to close again you will get 100 different timings for it to close again.
From a few seconds which is acceptable, to in bad cases over 40 seconds.
This certainly does badly affect emissions as well as performance.

As Mike says above the emissions test for diesels only looks at soot in the exhaust not NoX. Far better to disable it than it not working correctly.

Russ

[grivas]

The problem with the EGR is that it sticks if it's not kept clean.

If you test a 100 cars with enabled EGR and rev each to 3000 rpm and let go of the accelerator which will then open the valve, if you look on T4 at the time taken for it to close again you will get 100 different timings for it to close again.
From a few seconds which is acceptable, to in bad cases over 40 seconds.
This certainly does badly affect emissions as well as performance.

As Mike says above the emissions test for diesels only looks at soot in the exhaust not NoX. Far better to disable it than it not working correctly.

Russ

What is the best and least disruptive way to disable the EGR valve, and how do you ensure that when disabled thus it is fully closed, or does that matter in the disabled state?

[BigRuss]

What is the best and least disruptive way to disable the EGR valve, and how do you ensure that when disabled thus it is fully closed, or does that matter in the disabled state?

The easiest way once it's been cleaned is to plug the vacuum pipe with a smooth shouldered screw and secure the pipe out of the way.

The EGR has a strong spring that keeps the valve closed so it won't open once the vacuum pipe is removed and plugged.

Russ