AGR: Why at Full Load?

Hi everyone.
I noticed a strange clicking sound in my Seat Leon 1.9 TDI (81KW TDI), which occurs simultaneously with the turbo whistle. It's most noticeable when accelerating from low RPM under load. The same clicking sound can also be heard, but much slower, when you open the hood and press the gas pedal and then release it (it clicks once each time). After searching for a while, I found the source. It was the valve for the EGR (Exhaust Gas Recirculation) system that was making the noise. I then disconnected the air hose (pneumatic?) while the engine was running and played around with it (you can see it on the left side, above the engine cover). After disconnecting the hose, I took it for a test drive, and the noise was gone. I stopped, reconnected the hose, and the noise didn't reappear, which was unexpected. This leads me to believe that the EGR valve flap was likely the cause of the noise. I can't say exactly how or why, but it probably got stuck somehow.

The sound my lion made can also be heard in healthy lions, but it's not usually as loud. It's heard simultaneously with the turbo whistle and can be described as a light clicking sound.

Okay, here's a really dumb question: Why does the EGR valve make a clicking noise under FULL THROTTLE at low RPM (it's been doing this before too!)? I thought the EGR valve shuts off in full throttle mode! So why does it make noise even on a healthy engine and under full throttle?

I've heard that with diesel engines, you can gain power in the partial load range by deactivating the EGR system. But people who need more power usually drive with the accelerator fully pressed, so in my opinion, it's pointless. However, why is the EGR system active at full throttle?

Has anyone here deactivated their EGR system, and with what results?



THUNEON

Hello,

thuneon wrote:

Hi everyone. I noticed a peculiar clicking sound in my Seat Leon 1.9 TDI (81KW TDI), which occurs simultaneously with the turbo whistle, and I investigated. You can hear it when you give it gas from the lower RPM range under load. The same clicking sound can also be heard, but much slower, when you open the hood and press the gas pedal and then release it (it clicks once each time). After searching for a while, I found it. The valve for the EGR (Exhaust Gas Recirculation) was making these noises. I then disconnected the air hose (pneumatic?) while the engine was running and played around with it a bit (you can see this thing on the left side, above the engine cover). Then I let the hose hang down and took it for a test drive. The noise was gone. I stopped and pressed the gas again. The noise didn't come back, contrary to my expectations.

"Well, it will probably be like you say."

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All of this leads me to conclude that the AGR valve was likely the source of those noises. I can't say exactly how or why, but it was probably stuck in some way.

The AGR valve doesn't have a flap. If there is a flap, it's located before the AGR valve, but it's not part of the AGR system itself. It only serves to soften the engine's shutdown process.

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The sound that my lion made can also be heard in healthy lions, but not as loudly. It is heard simultaneously with the turbo whistling and can be described as a slight clicking sound.

My girlfriend only has a cat, but it doesn't meow, it makes a "maunzing" sound.

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Now, a really dumb question: Why does the EGR valve click when running at

FULL THROTTLE

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in the lower RPM range (it's been like that before too!)?

I have no idea which valve you're referring to right now. Are you talking about the valve plate of the EGR itself, or the solenoid valve that controls it?

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I think the EGR system shuts off in the full load range?!

Yes.

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Why does this thing then also make noises even with a healthy engine and full throttle?

There might be a bag of shells on your AGR valve.

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I know from diesel enthusiasts that you can extract more power in the partial load range by deactivating the EGR system. But if you need more power, you floor the accelerator, so in my opinion, it's nonsense.

IMHO, you absolutely haven't understood anything at all why it's not a disaster if the thing is 'broken'.
Please read the article again.

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But why is the EGR running at full load?!

I've never seen it running before, and it's always been off even under full load.
Perhaps you should read the article about AGR again.

}Has anyone of you deactivated their EGR system, and with what success?}
Who would be so foolish as to admit to driving something like that in public?
Of course, no one would drive a car with a disabled Diesel Particulate Filter (DPF) on public roads, as this would invalidate the vehicle's operating license and could also lead to prosecution for tax evasion.

For any further questions, I recommend using the search function of this forum, using the keyword 'AGR'.
Best regards, Rainer.