Hissing Noise, Little Air? Check Solenoid Valve.

Hi everyone.

"Recently, I've noticed something with my 1997 AGR: after about 1-2 seconds of full throttle..."
It starts to whistle loudly. But it's not the usual howling sound you get with a faulty turbo, but rather a high-pitched "fffftttt" sound.
It produces virtually no emissions.

I connected my car to VAG-COM and discovered that the boost pressure already reaches 1.4 bar at 2000 RPM. However, I must mention that the car has been chipped (tuned).
But still, it seems like a bit too much to me.

My suspicion is that the magnetic valve for the boost pressure control might be faulty. It currently has 175,000 kilometers on it.

What do you say?
How can I determine if the problem is with the solenoid valve?

Hi Tagessuppe,

Often, the magnetic valves for turbocharger pressure regulation and the EGR system are the same -> if this is the case for your specific engine code, you can swap them for testing purposes.

Please send me a log file.

A single measurement point at 2000 RPM and 1.4 bar doesn't tell us much.

What is the target value?
Does the actual value adjust to reach the target value?

Do you feel (while the engine is running) that the valve is being actuated in a timed manner?

Measure the voltage at the relay (ideally using an LED, which should blink frequently).

What does VAGCOM say about the control (valve lift) of the valve?

Questions upon questions .

m;

@ MARCO

NOPE!!!

The AGR is a wastegate turbocharger, which means it has an underpressure valve for the AGR system and an overpressure valve for the turbocharger itself.

There is ABSOLUTELY no exchanging allowed!

m;

Exchanges are only possible for VTG tractors .

Marco wrote:

Often, the magnetic valves for turbocharger pressure regulation and the EGR system are the same -> if this is true for your specific engine code (MKB), you can swap them for testing purposes.

That's a good thing. After all, I don't need the AGR anymore ).

Unfortunately, I haven't been able to figure out the log file issue yet.

I click the box during the measurement run, and the only thing that...
then a value is stored in the log file.
I really don't know what I'm doing wrong.
I'll be getting the full version soon. Hopefully, it will work then.

@ MARCO

NOPE!!!

The AGR is a wastegate turbocharger, which means it has an underpressure valve for the AGR system and an overpressure valve for the turbocharger itself.

There is ABSOLUTELY no exchanging allowed!

m;

Swapping is only possible for VTG tractors .

Hi dieselmartin,

That's why I also wrote 'if this applies to your MKB...' .

dieselmartin wrote:

What does VAGCOM say about the control (valve lift) of the valve?

Hmm... I should have thought of that.

I haven't been using the software for very long.
That's why I'm not familiar with all the functions yet.

"So, logging also worked for me with the share version."

The key ratio is located in block 11, the last value.

There was a thread recently where someone was having turbocharger issues, which were clearly visible in the extremely aggressive throttle response (it was almost like full boost was being applied in one direction or another).

After replacing the N75 valve, everything was working fine again.

m;

Hi,

If the boost pressure consistently exceeds 1.4 bar when driving at full throttle, and the engine control unit (ECU) does not switch to a failsafe mode, then your tuning chip is defective.

Best regards, Rainer.

... and soon, the engine as well .

While the last two posts probably won't be helpful, who knows what kind of shady stuff might have been done inside the chip...
If it turns out that the pressure is indeed consistently 1.4 bar, it would be better to install a different chip.
It's better to have a limp mode with reduced performance than a broken engine/turbocharger. With limp mode, you at least know something is wrong before it completely breaks down.
Take a look at the technical article about the vacuum/pressure control hose system for the engines; I don't remember the exact name of the article right now.

At a pressure of 1.4 bar, it's conceivable that hose clamps or jubilee clips on the charge air pipes, etc., could slowly loosen because they are not designed for such high overpressure. Therefore, the hissing sound could simply be caused by the excessive boost pressure.

Best regards, Rainer.

So, I went on a measurement trip this weekend.

Measurement block 11 and the last value.
The idle speed is somewhere between 91-97%.
When accelerating, it drops down to 21%.

Unfortunately, I have absolutely no idea what that could mean.

Please provide an explanation .

Tagessuppe wrote:

So, I went on a measurement trip this weekend. Measurement block 11 and the last value. The idle speed is somewhere between 91-97%. When accelerating, it drops down to 21%. Unfortunately, I have absolutely no idea what that could mean. Please provide an explanation

.
Keyboard input. Turbocharger boost pressure valve in %.

http://www.dieselschrauber.de/Solldaten_4_Zylinder_VE.html

How is it now, are the 1.4 bar of pressure consistently above 2000 min ^-1 when running at full throttle?

It's hard to say.

It's not easy to keep your eyes on the laptop for long when driving my diesel car at full speed, because something might end up on the hood that shouldn't be there.


Unfortunately, I still haven't managed to create a log file.
Where do you store your log files?
How many log files can you store in a folder?

Quote:

Where do you store your log files?

VAGCOM saves its logs to its log directory.

Quote:

How many log files can you store in a folder?

Since you can specify the filename beforehand, as many as you want (provided you give them different names

m;