Just What Good Is The EGR Valve? - Page 2

Mike Noc · 9th August 2022, 18:45

Quote:

Originally Posted by Tasng4

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 · 9th August 2022, 21:21

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 · 11th August 2022, 12:23

Quote:

Originally Posted by 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

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 · 11th August 2022, 13:20

Quote:

Originally Posted by grivas

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

9th August 2022, 21:21	#12
BigRuss Premium Trader 75 CDT Tourer,2.5 Launch Saloon, Omipro MG/Rover (T4) Join Date: Jul 2007 Location: Liversedge, West Yorkshire Posts: 5,405 Thanks: 1,105 Thanked 1,340 Times in 661 Posts	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 __________________ Replacement Key Service http://https://the75andztclub.co.uk/...d.php?t=244732 Full T4 Testbook diagnostics available. Diesel ECU repair and replacement. Options enabled or disabled as required. Diesel X-Power 135 and 160bhp, Rover 1.8T 150 to 160 MG 160 V6 to 177 upgrades available P.M. for details.