PD AUY Noises: Troubleshooting & Solutions

Hello,

I'm having a problem with some noises. It sounds like a 'scraping' noise, occurring about 3-4 times in a row, and it happens at an RPM between 1200 and 1600. You can't hear anything when the car is stationary. You can hear it when driving under load. I would also say it's more noticeable in 4th gear, especially when gently pressing the accelerator.
Is it possible to influence this? Everything is fine at speeds above 2000 RPM. Furthermore, there are sometimes hesitations during acceleration, as if the gas pedal is suddenly released. This happens within the same RPM range as mentioned above, sometimes with a noise and sometimes without.
I should mention that I mostly drive in the city and on short trips.
Could it be that the EGR valve is sticking or fluttering due to potential carbon deposits, and that this is causing the noises?
I also have the feeling that the performance sometimes changes.
Sometimes more, sometimes less. LMM is quite new.

Does anyone have a suggestion?

Hello,

Could it be?

Quote:

"Snoring, rattling, or humming sounds coming from the front left wheel well, within the RPM range of 1500-3000 RPM. Cause. Starting with model year '99, a new cold air intake system was implemented, drawing air in through the front left wheel well. Due to this modification, vibrations may occur between the wheel well and the fender liner, potentially causing the fender liner to flutter. Solution: By attaching a strip of foam to the inside of the fender liner, the air gap is reduced.

I don't think so. Anything related to suction is a legal issue.
I think I forgot to mention, but it's a Galaxy.
It only happens when I'm driving. Based on the location, I would say it's coming from somewhere in the middle to the right side, near the splash guard.
The problem is that it only locates when you are driving.
There are still valves on the injection molding machine, probably for controlling the boost pressure, etc.
But how and by what the noise is created is still unclear.


Thank you, Mirko.

Hi Mirko,

My tractor might be making the same noises.
The engine is idling low, and you can clearly feel the turbocharger building boost and torque, and then you release the gas --> "schripp schrapp schrupp" (a sound indicating a misfire or hesitation).
It's sometimes stronger and other times weaker.
The noise cannot be reproduced at speeds above approximately 1500 rpm.

Since I observe a synchronous and stepwise (!!) drop in boost pressure during noise events on my LDA, but the impeller shaft isn't rubbing anywhere, I suspect that flow separation or a similar issue is occurring at the turbine.
And avoid abruptly releasing the accelerator pedal below 1500 rpm, because then you will reliably experience silence .

Hello Ulf,

Thank you for your reply.
The same applies to me. However, it only happens when I suddenly release the accelerator.
If you gently move the pedal, you can create different sounds.
Good would be suitable for building up boost pressure.
Der Witz, habe heute noch mit jemand gesprochen. Er hatte mir das mit dem Geräusch beschrieben, wann und wie usw. Ohne das ich ihm was davon erzählt habe, konnte er mir das genau beschreiben. Genau das gleiche wie bei mir. SThat's kind of weird.
Is this considered normal, or not? Is anyone responding?
Initially, there was nothing.

Or should we simply continue driving and observe ?

Mirko wrote:

Is anyone signing up yet?? Initially, there was nothing. Or should we simply continue driving and observe

?

I've been doing the latter for about a year.

I've been meaning to extend the VTG shaft for a while now to mitigate the pressure buildup at low RPM. However, something else has always seemed more important until now...

If you want to try it (at your own risk!), feel free.

That reminds me of something.

Always in a cold state, with a temperature below 0°C.
There was a brief squeak when I turned off the gas.
I went to the workshop, and they followed the 'customer is stupid' approach.
It's just the normal sound of a tube device.
Well, all I could do was give a thumbs-up.
Over the weekend, I had been searching for it myself and eventually found it.
VTG adjustment lever, which was moved whenever the vacuum actuator activated it.
The axle was squeaking where it connects to the VTG rod, near the pivot point of the lever.
So, just the shaft, not the entire VTG housing.
Wenn die nun mit der Zeit schwergängig wird, bleibt doch der Ladedruck länger als notwendig. OWHO???
That would be a good idea.

Mirko wrote:

VTG adjustment lever, which was moved whenever the vacuum actuator activated it. The axle was squeaking where it connects to the VTG rod, near the pivot point of the lever. So, just the shaft, not the entire VTG housing. Wenn die nun mit der Zeit schwergängig wird, bleibt doch der Ladedruck länger als notwendig. OTHE???

Hi Mirko,

The basic principle is correct, but the reaction time of the VTG can be particularly well seen in the overpressure of the charging pressure (if you have an LDA on board).
My VTG (Variable Transmission Gear) is responding normally again thanks to the larger capacitor, but I'm still experiencing these(?) noises.