Close AGR valve, why???

Hello,

I'm really curious why, in many posts, closing the AGR valve is already being done or recommended as the first step.

Sometimes, you get the feeling that you're starting at a disadvantage, even with a fully functional AGR system.

To the best of my knowledge, the EGR system is designed to prevent nitrogen, an otherwise inert gas, from reacting with excess oxygen in excessively hot zones of the combustion process to form NOx.

(NOx refers here to all possible compounds of nitrogen N and oxygen O.)

Therefore, EGR only displaces the excess air that is not necessary for the combustion of the injected amount of fuel.

Therefore, we can't even expect an increase in performance!

Best regards,
Hardy disc.

Hi.

You are right; it is forbidden and unnecessary to restrict "vehicles kept in a way that respects their nature," especially when they are often driven at full throttle.
Especially in engines that are frequently used in areas with high EGR activity, are driven mostly on short trips, are older, or produce a lot of soot, the EGR system, intake manifold, etc., can become clogged. This restricts airflow to the engine, and the EGR system itself can then cause even more soot production.
"In newer engines, it is no longer possible to disable the EGR system without generating an error code. Often, disabling the EGR is only used for troubleshooting when the EGR valve is constantly open or stuck, or when the EGR valve itself is defective."
Due to the legal and environmental policy aspects (classification of exhaust emissions into a category), this measure cannot be permanently installed.
However, even the TÜV (German technical inspection agency) doesn't notice it.
Hopefully, I've contributed to the formation of opinions.

teileklaus wrote:

Due to the legal and environmental policy component (classification of exhaust emissions into a category), this measure cannot remain permanently

in place. That's not entirely correct, Klausi. In reality, the car is no longer allowed to travel even a single meter on public roads. The BE (Business Entity) is deactivated and expires immediately!

Yes, yes, I understand, but clever workshops also use this method of temporarily sealing something to rule out potential problems, right?
And I wouldn't necessarily criminalize that.

As you already mentioned, a portion of the exhaust gas will be mixed with fresh air.
(between the turbocharger and the intercooler).
The required amount of air is regulated when the EGR valve is open by a defined...
Partial exhaust system replaced.
This reduces the amount of fresh air controlled by the mass airflow sensor.
This is a measurement used to calculate the injection quantity.
<edit>Further research: There are LMM signal compensation mechanisms in various [systems/devices/etc.]. STGs.

Furthermore, the back pressure of the exhaust gases before the turbocharger is reduced.
This results in a slower rate of change/increase in the speed of the...
Turbos, often referred to as 'throttle response.'

Empirically verified and successful.

Sure, here's the translation:

'Best regards.'

hardyscheibe wrote:

Hello, I'm really curious why, in many posts, closing the AGR valve is already being done or recommended as the first step. Sometimes, you get the feeling that you're already at a disadvantage with a functional EGR system from the start!

The owners of the engines whose beneficial EGR systems show effects like those in the photos here /viewtopic.php?t=3095 are actually at a disadvantage from the beginning if they ever need to use their engine's maximum paper-based power output...

Quote:

Not quite, Klausi. Actually, the car is no longer allowed to travel even a single meter on public roads. The BE expires immediately upon deactivation!

It probably won't trigger any error codes related to emissions either, but what can you do? Load it onto the truck, and in the workshop, place it on the air-conditioned roller test stand, so that a brainlessly defined law is satisfied?!

For many older vehicles, the average exhaust emissions, measured across all pollutant components with a closed ARF (Abgasrückführung - Exhaust Gas Recirculation), will appear better.

Hello,

Thank you for the comprehensive answers. The misunderstanding has now been cleared up!

I've also seen carbon buildup in the intake manifold many times, but I believe it has become significantly less frequent with better (more modern) engine oils (currently using Agip Formula Future 5W30).

Temporarily closing the AGR (Abgasrückführung) system for diagnostic purposes is permissible. E. Completely harmless, you can (should) even drive to the workshop with a burning MIL (immediately)!

Anything that goes beyond that will be a thing of the past with the introduction of the blue environmental sticker!

Greetings, Hardy's disk.

hardyscheibe wrote:

Temporarily closing the EGR valve for diagnostic purposes is, in my opinion, completely harmless; you are even allowed (should) to drive to the workshop immediately with a burning MIL (check engine light)!

You will be accused of intentional tampering for doing this! Therefore, you are knowingly committing a crime. If the MIL (Malfunction Indicator Lamp) comes on while you are driving, there's nothing you can do about it, and you are allowed to drive directly to the workshop.

Hello everyone,
Just a quick note, and regarding... Test drives in/with various new cars.
Do the newer (larger) engines, which often have a 7-speed automatic transmission or a long-geared 6th gear, and which typically operate at around 2,000 RPM on the highway at 150 km/h, essentially function as long-distance vehicles, constantly exhibiting noticeable acceleration rates as they travel? Is there a graph available that shows the partial load and AGR (Abgasrückführung - exhaust gas recirculation) values?
I am unable to translate "haithamina" because it does not appear to be a word or phrase in the German language. It may be a misspelling, a proper noun, or a term from a specialized field. If you can provide more context or clarify the intended meaning, I would be happy to assist you with the translation.

"If you have a lot of time, you can create a dataset without using the AGR (Abgasrückführung) system. You can use VCDS to log the amount of air the engine is drawing in under different load conditions, and then compare that air mass to the air mass measured with the stock AGR system."

Then you can see which AGR (AdBlue) rates are being used in different operating modes. Without any further options for interaction, this information is likely to be of limited interest, and the only element that might be relevant to an interested user is the right foot.
Generally, as the load increases, the AGR (Abgasrückführung) rate decreases. Therefore, if you want to minimize carbon buildup, you should always maintain a constant speed on the highway. Especially truck drivers who, at +2 km/h, block all lanes for kilometers just to pass another truck, are operating in an extremely active "aggressive driving" zone, which ultimately leads to the car not functioning properly anymore if the driver ever wants it to.

Best regards, Rainer.

Is there really no way anymore to influence the AGR (Abgasrückführung - exhaust gas recirculation) on the newer models? The 'clogging' issue has been addressed for a while, but 'downsizing' (presumably referring to adjusting the AGR settings) isn't working on our BMN engine... (incorrect login...)

dieselschrauber wrote:

If you have a lot of time, you can create a dataset without using the AGR (Abgasrückführung) system. You can use VCDS to log how much air mass the engine is drawing at different load conditions, and then compare that air mass to the air mass with the stock AGR system.

Hi Rainer,
Okay, I understand. What I wanted to say is: I'm quite familiar with this issue regarding my 1.9 TDI. Especially on highways where speeds exceed 140 km/h, the engine revs so high that the AGR (variable valve timing) system becomes irrelevant.
If I look at other, modern engines with corresponding transmissions, they operate at around 2,000 RPM at average highway speeds in Germany, and therefore have correspondingly high AGR (Abgasrückführung) rates when "cruising." They should also be relatively efficient, as indicated. V speed, plus 2 km/h driving profile.
I am unable to translate "haithamina" because it does not appear to be a word or phrase in the German language. It may be a misspelling, a proper noun, or a term from a specialized field. If you can provide more context or clarify the intended meaning, I would be happy to assist you with the translation.

Hello,

I wanted to disable the AGR valve in an Opel Zafira to be sure that this valve, which occasionally jams, is actually responsible for the cold start problems (in addition to the occasional loss of power), since the valve costs €648!

Due to its modern, water-cooled design, this valve is an integral part of the intake manifold/AGR system and cannot be sealed with gaskets or plates.

Similarly, both mechanical locking and blocking, as well as unplugging the device, will immediately trigger emergency mode.

The two remaining options would be to separate the valve from the actuator (Flex).
or to connect a second, working valve (haha) to the wiring harness during the test.

Fortunately, the valve is already available online for €220, and I explained to the customer that no one wants to start their day by having to deal with their own problems, so the issue is resolved.

The conclusion from all of this is: the newer the cars, the more deeply integrated the electronics are. There's no more room for trial and error!

On the other hand, history also shows that the legislator has achieved its goal: a vehicle that exceeds its emission values at the time of registration or otherwise does not meet the requirements will, at the latest, fail the next vehicle inspection (HU). AU, discovered and removed from circulation.

Best regards,
Hardyscheibe.

Quote:

They should also work quite well,

Not necessarily.
And the Golf experienced its first 122,000 km (approximately 76,000 miles) at this constant speed -> the EGR system seems to be influenced by Russian technology. And that's after another 8,000 km of city driving.

Quote:

Due to its modern, water-cooled design, this valve is an integral part of the intake manifold/AGR system and cannot be sealed with gaskets or plates.

One thing has nothing to do with the other.
In VW vehicles, the cooled EGR valves are also lockable, but the engine control unit (ECU) detects the locking.

m;

dieselmartin wrote:

One has nothing to do with the other. At VW, the cooled AGR valves are also lockable - however, the engine control unit (ECU) detects the locking.

You're right, Martin, but I know what he means. I recently had a 2.2 DTI with AGR problems as well. The problem there is that there is no separate pipe for the EGR system; the exhaust gases travel through the cylinder head to the valve.