AGR Failure: Is It Technically Risky?

Hello everyone,

Unfortunately, it's been quite a while since someone posted here that, after disconnecting the EGR valve, the turbocharger continued to run for a longer period... or something similar.
What is the general situation like right now?
Can a "faulty" EGR valve potentially cause damage to other parts of the vehicle?
I have a 2.5 TDI AEL engine.
If this question has already been definitively answered, please excuse me. I haven't been online for a long time... due to building and related activities.

Greetings and thank you .
Wool.

@ wool

Okay, so about two years ago, I had the EGR valve deactivated on my 'old man's' Allroad, based on the recommendation of my workshop. He (the owner) said, without really knowing why, that the car would run a little better... I hardly ever drive the car, so I can't really tell if it makes a difference.

I disconnected the EGR valve on my car and noticed significant differences.

1. After turning the key, the engine runs for 1-2 seconds (it doesn't do this with the EGR system - in that case, it starts immediately).

2. It consumes approximately 0.3 to 0.5 liters less.

3. The boost pressure (as indicated on the analog display) increases slightly faster, which would also explain the somewhat better acceleration.

I can't say much more about it. The workshop manager just mentioned that it would definitely be better for the catalytic converter and the intake manifold, as they would otherwise become very contaminated (especially with the 2.5-liter engine).

And all I can say about that is what has already been said multiple times:
Specifically, when the EGR system fails, the combustion chamber temperature at partial load is higher than when the EGR system is functioning correctly.
Sure, the combustion is cleaner, but I think it's very difficult to actually feel a difference in performance...
In my opinion, the problem arises primarily when the engine is run at full throttle for a long time (during which the EGR system is typically deactivated) and then suddenly enters a partial load range. In this situation, the combustion chamber temperature can be very difficult to reduce again, especially if no exhaust gases are being fed back into the combustion chamber.

@edward

Shouldn't the oil temperature also increase in the partial load range?
How about cars with engine tuning? From my experience, I can say that my oil temperature is about 5-10°C lower in all gears compared to the stock values (using the same oil and with no other modifications).

Or are the engines always warmer in the first 8,000 kilometers and then become cooler as the mileage increases? That would be news to me...

'It already ran hot, with oil temperatures reaching 120-125°C under load. Now, with the chip and the EGR valve disconnected, it's even worse. Unfortunately, it also takes longer to warm up in the winter...'

How do you explain that, in your opinion? I sometimes drive in the winter with cardboard in front of the radiator and the EGR valve disconnected, so that the engine warms up faster on short trips...

I can't really comment on the Audi (it has a heated seat).

Hi,

Check this out:
/viewtopic.php?t=1456&highlight=

Best regards, Christian.

Deleted upon request.

Hi,

Whether the EGR system has a technical purpose is certainly a matter of debate. (It's intended to reduce NOx emissions.)
Now, I mostly drive my Audi in the partial load range. Sometimes, it still "bites" me (meaning the engine still exhibits some unwanted behavior), but then I let it run... but that's quite rare.
Several Audi people have told me that the 5-cylinder engine is particularly prone to carbon buildup. And that's exactly what I want to prevent with the modified EGR system. Because, as is well known, this leads to narrower intake passages, turbulence, and consequently, significantly poorer cylinder filling, resulting in a loss of power. People then compensate for this by pressing the accelerator harder... well...
I'll disconnect it for now, and when the weather is better, I'll remove the intake manifold and verschandeln it thoroughly. Let's see how far I can go into the cylinder head while I'm at it...
I really don't feel like disassembling the ZK to verschandeln it...
Does anyone here know a better solution for thoroughly removing soot residue?

Regards,
Wool.

P.S. And by the way......happy New Year to everyone!

Hi,

I have a question regarding the AGR (Abgasrückführung) and the turbocharger.
When the AGR (Abgasrückführung - Exhaust Gas Recirculation) system failed on my Seat, I noticed the following.
After turning off the engine, when the engine was still warm, one could hear...
The turbocharger is significantly lagging, by about 2-3 seconds, and there was also...
Geräusch zu hören als wenn ein Kugellager trocken läuft. Beides is at.
A properly functioning EGR valve should not be audible.
I think it's already clear that the turbocharger continues to run for a longer period, because of...
defective AGR valve means more exhaust gases are available.
Should I be concerned about a potential EGR valve failure based on these noises?
Are the noises normal?
'By the way, the oil consumption is normal, about 1 liter per 15,000 kilometers. The car has a mileage of 73,000 kilometers.'

If the turbo continues to run for a longer period after the engine is switched off, it could only mean that the engine control unit opens the EGR valve when the engine is turned off, especially if it is not already slightly open during idling in these engines.
The exhaust gas flow remains stagnant when the engine is idling. The turbocharger is most effectively braked when the compressor is working, i.e., when it is forcing air against a resistance. This requires (unless a cylinder is constantly in the exhaust stroke due to valve overlap) that the EGR valve is slightly open.
The issue of "running down" is definitely a problem because when the engine is stopped, the oil pressure also drops.
I don't know if the storage facilities are suitable for that.
An electric oil pump for the turbo was only used in gasoline engines to prevent carbon buildup in the bearings (or was it only an electric water pump?).

Hi,

@christians
'The EGR valve in my car stays open for about 2 minutes at idle.'
Then it closes, I have no idea why.
I think the EGR valve should remain open for a while after the engine is turned off.
It remains open until the vacuum collapses.

Hi,

@christians
'The EGR valve in my car stays open for about 2 minutes at idle.'
Then it closes, I have no idea why.
I think the EGR valve should remain open for a while after the engine is turned off.
It remains open until the vacuum collapses.

Yes, that's exactly it...

Regarding pollution, I can only say that with a functioning EGR system on the 5-cylinder AAT engine, the level of pollution is extremely high!

We just had a head removed (110,000 km and the timing belt broke, you know how it is ).

As I said, it looked pathetic .
Everything is black and somehow 'oily' in the intake manifold.
a really thick layer.
This layer was also somehow baked onto the intake valves (on the intake side).

It's made me think about whether I should also disable the AGR (Acoustic Retrofit System) in my car.
Wouldn't it actually be possible to do that with software?



Please provide the German text you would like me to translate into English.

The pollution is indeed a problem. I recently removed 200 grams of carbon deposits from my intake manifold.
In theory, and especially with a new car, this isn't a problem: In the partial load range, the engine only produces minimal smoke, so there's not much that can get dirty.
Either the clamping tendency is already built-in, or the control system is not responding quickly enough to changes in the load state.
A monitoring system within the EDC (Engine Control Unit) could suffice to detect failing EGR valves that are stuck in the closed position. Alternatively, a more powerful vacuum actuator could be used.
As the AGR currently operates, it seems primarily designed to facilitate the registration of new cars.
I'm not sure why the five-cylinder engines are particularly prone to failure, but I can imagine that the attractive turbochargers used in them might play a role.

christians wrote:

The pollution is indeed a problem. I recently removed 200 grams of carbon deposits from my intake manifold. In theory and/or with a new vehicle, this isn't a problem: In the partial load range, the engine only produces minimal smoke, so there's not much that can get dirty.

Hi Christian,

I can certainly relate to that... it was quite a struggle until everything was out .

While no soot is visible in the partial load range, something is still present, and over time, this, along with the oil droplets, will likely cause deposits to form!

So, make sure to clear your bronchi and quit smoking .

Best regards, Christian.

Hi Dirk,

I'm not familiar with the AAT, but I doubt there's a significant difference between it and the AEL.
provide.
The EGR valve is controlled by a valve located on the mass airflow sensor housing.
The mass airflow sensor (MAF sensor) is much more important. I'm sorry I can't explain it very well because I'm not a mechanic, but the MAF sensor measures the amount of air being drawn in and sends that value to the engine control unit (ECU). The ECU uses this value to calculate the amount of diesel to inject.

See you soon, and happy tinkering...

Regards,
Wool.

Hi,
I drive an Ibiza with a 96kW TDI engine (ASZ). Is there an error code stored in the engine control unit if you block the EGR valve with a metal plate?

Best regards and thank you!
Michael.

Here's a small note about this:

As part of the OBD harmonization process, the monitoring of the EGR (Exhaust Gas Recirculation) system will be implemented. In the USA, it is already a requirement.

Just a heads-up. I don't have the current regulations in front of me, but starting this year, diesel vehicles are also required to support OBD-II. I can't say for sure whether the EU regulations already mandate an EGR control (I'll check on Monday), but technically, it's definitely feasible now.

CU Gremlin.